DS2422 1-Wire Temperature/Datalogger with Datalog Memory GEN
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19-4866; 8/09
DS2422
1-Wire Temperature/Datalogger with Datalog Memory
GENERAL DESCRIPTION
DS2422 temperature/datalogger combines core functions fully featured datalogger single chip. includes temperature sensor, realtime clock (RTC), memory, 1-Wire® interface, serial interface analog-to-digital converter (ADC) well control circuitry charge pump. charge pump peripherals that added build application-specific dataloggers. Without external ADC, DS2422 functions temperature logger only. DS2422 measures temperature and/or reads user-defined rate. total 8192 8-bit readings 4096 16-bit readings taken equidistant intervals ranging from 273hrs stored.
FEATURES
Automatically Wakes Measures Temperature and/or Reads External Stores Values Datalog Memory 16-Bit Format On-Chip Direct-to-Digital Temperature Converter with 8-Bit (0.5°C) 11-Bit (0.0625°C) Resolution Sampling Rate from 273hrs Programmable Recording Start Delay After Elapsed Time Upon Temperature Alarm Trip Point Programmable High Trip Points Temperature Data Alarms Quick Access Alarmed Devices Through 1-Wire Conditional Search Function Bytes General-Purpose Memory Plus Bytes Calibration Memory Two-Level Password Protection Memory Configuration Registers Unique Factory-Lasered 64-Bit Registration Number Assures Error-Free Device Selection Absolute Part Identity Built-in Multidrop Controller Ensures Compatibility with Other Maxim 1-Wire Products Directly Connects Single Port Microprocessor Communicates 15.4kbps Standard Speed 125kbps Overdrive Mode -40°C +85°C Operating Range 2.8V 3.6V Single-Supply Battery Operation Power (1.2µA Standby, 350µA Active)
APPLICATIONS
Temperature Logging Cold Chain, Food Safety, Science High-Temperature Logging (Process Monitoring, industrial Temperature Monitoring) General-Voltage Datalogging (Pressure, Humidity, Light, Material Stress)
CONFIGURATION
VIEW
VPAD SCLK SDATA CNVST AGND ALARM
TEST_CG VBAT PUMP_ONZ TEST_RX TEST_SPLY
ORDERING INFORMATION
PART TEMP RANGE PIN-PACKAGE
24-lead, 300-mil DS2422S+ -40C +85C +Denotes lead(Pb)-free/RoHS-compliant product. Commands, Registers, Modes capitalized clarity.
1-Wire registered trademark Maxim Integrated Products, Inc.
Note: Some revisions this device incorporate deviations from published specifications known errata. Multiple revisions device simultaneously available through various sales channels. information about device errata, click here: www.maxim-ic.com/errata.
DS2422
ABSOLUTE MAXIMUM RATINGS*
ALARM, PUMP_ONZ, SDATA, SCLK, CNVST, VPAD, Voltage ALARM, PUMP_ONZ, Combined Sink Current Operating Temperature Range Junction Temperature Storage Temperature Range Soldering Temperature -0.3V, 20mA -40°C +85°C +150°C -55°C +125°C IPC/JEDEC J-STD-020A
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device.
ELECTRICAL CHARACTERISTICS
(VPUP 3.0V 5.25V, VBAT 2.0V 3.6V, VPAD 3.0V 5.5V, -40°C +85°C.)
PARAMETER Standby Supply Current Ground Current General Data 1-Wire Pullup Resistance Input Capacitance Input Load Current High-to-Low Switching Threshold Input Voltage Low-to-High Switching Threshold Switching Hysteresis Output Voltage SYMBOL IBAT1 IBAT0 IGND RPUP CONDITIONS VBAT 3.0V, VBAT 3.6V, Applies individually GND, AGND (Note (Notes (Notes VPUP, VBAT 3.6V (Notes (Notes (Notes 0.09 0.15 71.5 1200 2000 UNITS
(Notes (Note Standard speed, RPUP 2.2k Overdrive speed, RPUP 2.2k Recovery Time (Note tREC Overdrive speed, directly prior reset pulse; RPUP 2.2k Rising-Edge Hold-off Time tREH (Notes Standard speed Timeslot Duration (Note tSLOT Overdrive speed, VPUP 4.5V Overdrive speed (Note Pin, 1-Wire Reset, Presence Detect Cycle Standard speed, VPUP 4.5V Standard speed (Note Reset Time (Note tRSTL Overdrive speed, VPUP 4.5V Overdrive speed (Note Standard speed, VPUP 4.5V Presence Detect High tPDH Standard speed (Note Time Overdrive speed (Note Standard speed, VPUP 4.5V Presence Detect Fall Time tFPD Standard speed (Notes Overdrive speed Standard speed, VPUP 4.5V Standard speed (Note Presence Detect tPDL Overdrive speed, VPUP 4.5V Time (Note Overdrive speed (Note Standard speed, VPUP 4.5V Presence Detect Sample tMSP Standard speed Time (Note Overdrive speed
63.5
DS2422
PARAMETER Pin, 1-Wire Write Write-0 Time (Note Write-1 Time (Notes Pin, 1-Wire Read Read Time (Notes Read Sample Time (Notes ALARM Output Output Voltage Leakage Current CNVST, SCLK Output Pins Output Voltage Output High Voltage PUMP_ONZ Output Output Voltage Output High Voltage SDATA Input Input High Voltage Input Voltage Leakage Current Serial Interface Timing Period PUMP_ONZ Fall CNVST Rise CNVST Pulse Width CNVST Fall SCLK High (First Clock) SCLK Period SDATA Setup Time SDATA Hold Time Real-Time Clock Accuracy Frequency Deviation Temperature Converter Operating Range Conversion Time (Note Thermal Response Time Constant (Notes Conversion Error (Notes Conversion Current tCONV RESP ICONV tRING tCPW tSCH tSCP tSDS tSDH Power-on default (Notes (Note (Note duty cycle (Note (Note (Note +25°C (Note -40°C +85°C (Note VBAT 8-bit mode 16-bit mode bits) package +10°C +60°C -40°C +85°C (Note VBAT 3.6V VBAT 2.0V VBAT 3.6V VBAT 2.0V SDATA 5.5V min./ month VBAT 3.6V, VBAT 2.0V, VBAT 3.6V, 0.5mA VBAT 2.0V, 0.5mA SYMBOL CONDITIONS Standard speed Overdrive speed, VPUP 4.5V (Note Overdrive speed (Note Standard speed Overdrive speed Standard speed Overdrive speed Standard speed Overdrive speed Sink current ALARM VPAD VPAD VPAD VPAD 1.95 1.95 1.95 UNITS
tW0L
tW1L
tMSR
-300
1260
Temperature Accuracy Graphs
DS2422
Note Note Note Note Note Note Note Note Note Note Note Note Note Note Note Note Note Note Note System Requirement Maximum allowable pullup resistance function number 1-Wire devices system 1-Wire recovery times. specified value here applies systems with only device with minimum 1-Wire recovery times. more heavily loaded systems, active pullup such that found DS2480B required. Capacitance data could 800pF when VPUP first applied. 2.2k resistor used pull data line, 2.5µs after VPUP been applied parasite capacitance will affect normal communications. Guaranteed design, production tested. VTL, function internal supply voltage. Voltage below which, during falling edge I/O, logic detected. voltage needs less equal VILMAX whenever master drives line low. Voltage above which, during rising edge I/O, logic detected. After crossed during rising edge I/O, voltage drop detected logic '0'. characteristic linear voltages less than earliest recognition negative edge possible tREH after been previously reached. Highlighted numbers compliance with published iButton standards. comparison table below. Interval during negative edge beginning Presence Detect pulse between time which voltage VPUP time which voltage VPUP. represents time required pullup circuitry pull voltage from VTH. represents time required pullup circuitry pull voltage from input high threshold master. This expected range when using crystal equivalent SN14J (12.5pF). Time reach temperature change; measured temperature transition step from +25°C +85°C. 2-point calibration trim must done achieve specified accuracy application note available help developers perform calibration writing trim registers properly orient error curve. duration user-programmable from (code 00h) 127.5ms (code FFh) with tolerance ±0.5ms. Delay Register, address 400h, details.
STANDARD VALUES DS2422 VALUES PARAMETER STANDARD SPEED OVERDRIVE SPEED STANDARD SPEED OVERDRIVE SPEED NAME tSLOT (incl. tREC) 61µs (undef.) (undef.) 65µs1) (undef.) 9.5µs (undef.) tRSTL 480µs (undef.) 48µs 80µs 690µs 720µs 70µs 80µs tPDH 15µs 60µs 15µs 63.5µs tPDL 60µs 240µs 24µs 60µs 287µs 28µs tW0L 60µs 120µs 16µs 60µs 120µs 7.5µs 12µs Intentional change, longer recovery time requirement modified 1-Wire front end.
DS2422
DS2422 Temperature Accuracy
3.500 3.000 2.500 2.000 1.500 Error (°C) 1.000 0.500 0.000 -0.500 -1.000 -1.500 -2.000 -2.500 Temperature (°C) Max. 0.1°C uncertainty Min. ±0.25°C uncertainty Max. ±1°C uncertainty Min. 0.1°C uncertainty Max. ±0.5°C uncertainty Min. ±1°C uncertainty Max. ±0.25°C uncertainty Min. ±0.5°C uncertainty
"Uncertainty" refers uncertainty temperature measurement when performing 2-point calibration trim described application note. These graphs assume 11-bit temperature conversion. accuracy improved further through software correction. application note referenced "Note previous page details.
DS2422
DESCRIPTION
pins NAME VPAD SCLK SDATA CNVST AGND ALARM TEST_SPLY TEST_RX PUMP_ONZ VBAT TEST_CG FUNCTION Operating voltage serial interface pads CNVST, SCLK, SDATA. Used level translation from VBAT-powered internal logic 5V-powered ADC. Connect VBAT serial interface used. Serial clock signal serial interface. connect directly corresponding MAX1086 pin. idle state low. Serial data serial interface. connect directly DOUT MAX1086. includes weak pulldown therefore idle state low. Conversion Start control signal MAX1086. idle state low. Analog ground. Ground reference external charge pump. First crystal pins real time clock crystal. standard 32KHz crystal used. accuracy device's real time clock largely dependent temperature characteristics crystal. Trace length from device crystal should minimized reduce their capacitive effect. Logic open-drain output with maximum on-resistance, operating range 5.25V. Power-on default OFF. Second crystal pins real time clock crystal. 1-Wire communication line, data input output. This also charges internal parasitic power that allows 1-Wire front device without VBAT supply. Common ground supply device VBAT. Connect (test pin) Connect (test pin) Signal control external charge-pump. signal polarity designed MAX619 charge pump/regulator. power supply device, typically battery. This supplies power parts device except 1-Wire front end. connect (test pin) connected
DESCRIPTION
DS2422 temperature/data logger combines core functions fully featured data logger single chip. includes temperature sensor, RTC, memory, 1-Wire interface, serial interface analog-to-digital converter (ADC) well control circuitry charge pump. charge pump peripherals that added build application-specific data loggers. Without external ADC, DS2422 functions temperature logger only. DS2422 measures temperature and/or reads user-defined rate. total 8192 8-bit readings 4096 16-bit readings taken equidistant intervals ranging from second hours stored. addition this, there bytes SRAM storing application specific information bytes calibration data. mission collect data programmed begin immediately, after userdefined delay, after temperature alarm. Access memory control functions passwordprotected. DS2422 configured communicates with host computing device through serial 1-Wire protocol, which requires only single data lead ground return. Every DS2422 factory-lasered with guaranteed unique 64-bit registration number that allows absolute traceability. extremely energy consumption conjunction with high level programmability makes DS2422 ideal choice low-cost data loggers that take millions measurements from energy single button cell.
APPLICATION
DS2422 allows design data loggers monitors with minimum number components. simple circuit Figure monitor body room temperature with 0.0625°C resolution. very high temperaturemonitoring applications, thermocouple connected analog-to-digital converter (ADC) through preamplifier, shown Figure internal temperature sensor DS2422 keeps track reference temperature, which needed accurately convert voltage reading thermocouple into actual temperature monitored object. less obvious application DS2422 inside major equipment. Besides temperature inside chassis, serial interface monitor digital signals, which parallel-clocked into external shift register CNVST then shifted into DS2422 through SDATA
DS2422 under control SCLK. DS2422 will activate alarm output measured temperature serial-input data reaches user-programmed high alarm threshold. This alarm then used shut down equipment enforce service call. contrast microprocessor-based data loggers, DS2422 does require firmware development. Software setup data retrieval through 1-Wire interface available free download from iButton website (www.ibutton.com). This software also includes drivers serial port 1-Wire interfaces routines access general-purpose memory storing application equipment-specific data files.
Figure Simple Temperature Logger
OSC_TEST TEST_EXT CLK_TEST TEST_CG
1-Wire DS9503 SM14J 32768Hz
DS2422
ALARM PUMP_ONZ PUMP_ONZ VPAD Leave open
BR1225R Lithium
DS9503
VBAT AGND TEST_SPLY TEST_RX CNVST CNVST SCLK SDATA SDATA
Figure Temperature Voltage Logger With Thermocouple
OSC_TEST TEST_EXT CLK_TEST TEST_CG Leave open ALARM PUMP_ONZ PUMP_ONZ VPAD 1.5V 200k
INA122
1-Wire DS9503 SM14J 32768Hz
DS2422
CNVST CNVST SCLK SDATA SDATA
Thermocouple Type
BR1225R Lithium
DS9503
MAX1086
CNVST SCLK DOUT AIN2 AIN1
Vin+
VBAT AGND TEST_SPLY TEST_RX
2.2k
VinRef
0.1F
Note: When using positive/negative thermocouple, offset voltage utilized through input INA122 amplifier. This voltage shifts output amplifier amount equal offset voltage allowing negative voltages read positive range MAX1086. This offset voltage obtained through simple resistor divider network (not shown).
DS2422
Figure DS2422 Block Diagram
1-Wire Port Function Control 64-Bit Lasered Parasite Powere Circuitry
Lithium circuitry powered battery unless otherwise specified
Memory Function Control
256-Bit Scratchpad
General-Purpose SRAM (512 Bytes) 32.768kHz Oscillator Internal Timekeeping Control Reg. Counters Register Pages Bytes)
Thermal Sense VPAD CNVST SCLK SDATA Powered VBAT Structures
ADC1
Calibration Memory Bytes)
Control Logic
Datalog Memory
PUMP_ONZ
OVERVIEW
block diagram Figure shows relationships between major control memory sections DS2422. device main data components: 64-bit lasered ROM, 256-bit scratchpad, 512-byte general-purpose SRAM, 256-bit register pages timekeeping, control, status, counter registers passwords, bytes calibration memory, 8192 bytes data-logging memory. Except scratchpad, other memory arranged single linear address space. data-logging memory, counter registers several other registers read-only user. Both register pages write-protected while device programmed mission. password registers, read password another read/write password only written never read. hierarchical structure 1-Wire protocol shown Figure master must first provide eight function commands: Read ROM, Match ROM, Search ROM, Conditional Search ROM, Skip ROM, Overdrive-Skip ROM, Overdrive-Match Resume. Upon completion Overdrive command byte executed standard speed, device will enter Overdrive mode, where subsequent communication occurs higher speed. protocol required these function commands described Figure After function command successfully executed, memory control functions become accessible master provide eight available commands. protocol these memory control function commands described Figure data read written least significant first.
DS2422
Figure Hierarchical Structure 1-Wire Protocol
Master 1-Wire Other Devices
DS2422 Command Level: Available Commands:
Read Match Search Conditional Search Skip Resume Overdrive Skip Overdrive Match Write Scratchpad Read Scratchpad Copy Scratchpad w/PW Read Memory w/PW Read Memory w/PW w/CRC Clear Memory w/PW
Data Field Affected:
64-bit ROM, RC-Flag 64-bit ROM, RC-Flag 64-bit ROM, RC-Flag 64-bit ROM, RC-Flag, Alarm Flags, Search Conditions RC-Flag RC-Flag RC-Flag, OD-Flag 64-bit ROM, RC-Flag, OD-Flag 256-bit Scratchpad, Flags 256-bit Scratchpad byte Data Memory, Registers, Flags, Passwords Memory, Registers, Passwords Memory, Registers, Passwords Mission Time Stamp, Mission Samples Counter, Start Delay, Sample Rate Register, Alarm Flags, Passwords Memory addresses 020C 020Fh Flags, Timestamp Flags
1-Wire Function Commands
DS2422-specific Memory Function Commands
Forced Conversion Start Mission w/PW Stop Mission w/PW
PARASITE POWER
block diagram (Figure shows parasite-powered circuitry. This circuitry "steals" power whenever input high. provides sufficient power long specified timing voltage requirements met. advantages parasite power two-fold: parasiting this input, battery power conserved; battery exhausted reason, still read.
64-BIT LASERED
Each DS2422 contains unique code that bits long. first bits 1-Wire family code. next bits unique serial number. last bits first bits. Figure details. 1-Wire generated using polynomial generator consisting shift register gates shown Figure polynomial Additional information about Dallas 1-Wire available Application Note Book DS19xx iButton Standards. shift register bits initialized Then starting with least significant family code, time shifted After family code been entered, then serial number followed temperature range code entered. After range code been entered, shift register contains value. Shifting bits returns shift register
DS2422
Figure 64-Bit Lasered
8-Bit Code 48-Bit Serial Number 8-Bit Family Code (41h)
Figure 1-Wire Generator
Polynomial
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
INPUT DATA
Figure DS2422 Memory
32-Byte Intermediate Storage Scratchpad ADDRESS 0000H 001FH 0020H 01FFH 0200H 021FH 0220H 023FH 0240H 025FH 0260H 027FH 0280H 03FFH 0400H 041FH 0420H 0FFFH 1000H 2FFFH
32-Byte General-Purpose SRAM (R/W) General-Purpose SRAM (R/W) 32-Byte Register Page 32-Byte Register Page Calibration Memory Page (R/W) Calibration Memory Page (R/W) (Reserved Future Extensions) Trim Register Page (R/W) (Reserved Future Extensions) Datalog Memory (Read-Only)
Page Pages Page Page Page Page Pages Page Pages Pages
DS2422
MEMORY
memory DS2422 shown Figure bytes general-purpose SRAM located pages through various registers control device fill page called Register Pages (details Figure Pages provide storage space calibration data. They alternatively used extension general-purpose memory. Trim Register Page holds registers that used tune timing serial data interface trim on-chip temperature converter. "datalog" logging memory starts address 1000h (page 128) extends over pages. memory pages reserved future extensions. scratchpad additional page that acts buffer when writing SRAM memory register page. data- calibration memory written time. access type register pages Trim Register Page register-specific depends whether device programmed mission. Figures show details. datalog memory read-only user. written solely under supervision on-chip control logic. special behavior write access logic (write scratchpad, copy scratchpad) recommended only write full pages time. This also applies register pages calibration memory. section Address Register Transfer Status details.
Figure DS2422 Register Pages
ADDR 0200h 0201h 0202h 0203h 0204h 0205h 0206h 0207h 0208h 0209h 020Ah 020Bh 020Ch 020Dh 020Eh 020Fh 0210h 0211h 0212h 0213h 0214h 0215h 0216h 0217h 0218h 0219h 021Ah 021Bh 021Ch 021Dh 021Eh 021Fh 0220h 0221h 0222h 0223h 0224h 0225h 0226h 0227h CENT Seconds Single Seconds Minutes Single Minutes 20h. 12/24 10h. Single Hours AM/PM Date Single Date 10m. Single Months Years Single Years Byte High Byte Threshold High Threshold Threshold High Threshold Byte High Byte Byte High Byte ETHA EDHA EHSS SUTA DLFS TLFS WFTA MEMC Byte Center Byte High Byte Seconds Single Seconds Minutes Single Minutes 20h. 12/24 10h. Single Hours AM/PM Date Single Date 10m. Single Months Years Single Years function; reads 00h) Byte Center Byte High Byte Byte Center Byte High Byte Configuration Code Function RealTime Clock Registers R/W; Access*
ETLA EDLA EOSC
Sample Rate Temp. Alarms Data Alarms Latest Temp. Latest Data T.Alm.En. D.Alm.En. Mis. Cntrl. Alm. Stat. Gen. Stat. Start Delay Counter Mission Time Stamp (N/A) Mission Samples Counter Device Samples Counter Flavor Cntrl.
R/W; R/W; R/W; R/W; R/W; R/W; R/W; R/W;
CENT
R/W;
DS2422
ADDR 0228h 022Fh 0230h 0237h 0238h First Byte Eighth Byte First Byte Eighth Byte Function Read Access Password Full Access Password (N/A) Access*
function; these bytes read 00h)
023Fh
Figure DS2422 Trim Register Page
ADDR 0400h 0401h 0403h 0404h 0405h 0406h 0407h 0408h 041Fh delay value function; undefined read) Temperature Counter Reset Byte Temperature Counter Reset High Byte Temperature Conversion Length Byte Temperature Conversion Length High Byte function; undefined read) (N/A) Function (N/A) Access* R/W; R/W; R/W;
Note: first entry column ACCESS TYPE valid between missions. second entry shows applicable access type while mission progress.
TIMEKEEPING CALENDAR
RTC/alarm calendar information accessed reading/writing appropriate bytes register page, address 200h 205h. readings valid, registers must read sequentially starting address 0200h. Some bits These bits always read regardless they written. number representation registers format (binary-coded decimal).
Real-Time Clock Alarm Register Bitmap
ADDR 0200h 0201h 0202h 0203h 0204h 0205h CENT min.
20hr AM/PM
Single Seconds Single Minutes Single Hours Single Date Single Months Single Years
12/24
10hr
10yrs
Date 10m.
DS2422 either 12-hour 24-hour mode. Hours Register (address 202h) defined 24-hour mode select bit. When high, 12-hour mode selected. 12-hour mode, AM/PM with logic being 24-hour mode, 20-hour hours). CENT bit, Months Register, written user. This changes state when years counter transitions from calendar logic designed automatically compensate leap years. every year value that either multiple device adds 29th February. This works correctly (but including) year 2100.
DS2422
SAMPLE RATE
content Sample Rate Register (addresses 0206h, 0207h) specifies time elapse seconds EHSS minutes EHSS between temperature/data logging events. sample rate value from 16383, coded unsigned 14-bit binary number. EHSS shortest time between logging events second longest (sample rate 3FFFh) 4.55 hours. EHSS shortest minute longest time 273.05 hours (sample rate 3FFFh). EHSS located Control Register address 0212h. important that user sets EHSS accordingly while setting Sample Rate register. sample rate 0000h valid must avoided under circumstances. This causes device enter into undefined state, requiring power-on reset restore trim settings recover.
Sample Rate Register Bitmap
ADDR 0206h Sample Rate 0207h Sample Rate High During mission, there only read access these registers. Bits cells marked always read cannot written
TEMPERATURE CONVERSION
DS2422 measure temperatures from -40°C +85°C. Temperature values represented 16bit unsigned binary number with resolution 0.5°C 8-bit mode 0.0625°C 16-bit mode. higher temperature byte always valid. 16-bit mode only three highest bits lower byte valid. five lower bits read zero. undefined device 8-bit temperature mode. outof-range temperature reading indicated 0000h when cold FFE0h when hot.
Latest Temperature Conversion Result Register Bitmap
ADDR 020Ch 020Dh With representing decimal equivalent temperature reading temperature value calculated (°C) TRH/2 TRL/512 (°C) TRH/2 mode, TLFS address 0213h) mode, TLFS address 0213h)
This equation valid converting temperature readings stored datalog memory well data read from Latest Temperature Conversion Result Register. specify temperature alarm thresholds, equation above needs resolved TALM (°C) Since temperature alarm threshold only byte, resolution temperature increment limited 0.5°C. TALM value needs converted into hexadecimal format before written temperature alarm threshold registers (Low Alarm address 0208h; High Alarm address 0209h). Independent conversion mode bit) only most significant byte temperature conversion used determine whether alarm will generated.
Temperature Conversion Examples
Mode 8-bit 8-bit 16-bit 16-bit decimal decimal (°C) -29.5 1.000 -29.3125
DS2422
Temperature Alarm Threshold Examples
(°C) 25.5 -10.0 TALM decimal
SERIAL DATA INPUT
addition temperature, DS2422 8-bit 16-bit digital information that receives through serial interface. This interface designed directly connect ADCs such MAX1086 other circuits that same interface timing. general timing serial interface shown Figure timing derived from on-chip ring oscillator, which generates signal. CNVST signal intended start analog-to-digital conversion. After conversion completed, SCLK signal becomes active rising edge clocks digital value into DS2422. PUMP_ONZ signal activate MAX619 charge pump convert battery voltage DS2422 into example, power additional circuitry.
Figure Serial Interface Timing
tRING PUMP_ONZ CNVST SCLK SDATA
tSCP tCPW tSCH
Figure Serial Interface Setup Hold Timing
tSDS tSDH
SCLK
SDATA
Data Valid
serial interface becomes active whenever DS2422 executes Forced Conversion command (see Memory/Control Function Commands) during mission, device data from serial interface. Regardless setup, DS2422 always reads bits from serial input. 16-bit result latest serial reading found address 020Eh (low byte) 020Fh (high byte). first read through serial interface always found address 020Fh. generates less than bits, internal weak pulldown SDATA makes missing bits read zero.
Latest Serial Data Reading Result Register Bitmap
ADDR 020Eh 020Fh HIGH
During mission, data logging from serial input enabled, HIGH byte (B15 always recorded. byte only recorded DS2422 16-bit logging serial input data. algorithm convert digital reading from serial interface into physical unit depends circuit that provides data DS2422. This algorithm needs reversed when calculating values alarm
DS2422 threshold registers that associated serial data input. registers data alarm thresholds located address 020Ah (Low Alarm) 020B (High Alarm). comparison based most significant serial input byte assumes that data represented unsigned binary number.
TEMPERATURE SENSOR ALARM
DS2422 Temperature Alarm Threshold registers (address 0208h, 0209h) store values, which determine whether critical temperature been reached. temperature alarm generated device measures alarming temperature alarm signaling enabled. bits ETLA ETHA that enable temperature alarm located Temperature Sensor Control Register. temperature alarm flags found Alarm Status Register address 0214h.
Temperature Sensor Control Register Bitmap
ADDR 0210h ETHA ETLA During mission, there only read access this register. Bits have function. They always read cannot written
Register Details
DESCRIPTION ETLA: Enable Temperature Alarm BIT(S) DEFINITION This controls whether, during mission, Temperature Alarm Flag set, temperature conversion results value equal lower than value Temperature Alarm Threshold Register. ETLA temperature alarms enabled. ETLA temperature alarms generated. This controls whether, during mission, Temperature High Alarm Flag set, temperature conversion results value equal higher than value Temperature High Alarm Threshold Register. ETHA temperature high alarms enabled. ETHA temperature high alarms generated.
ETHA: Enable Temperature High Alarm
SERIAL INPUT ALARM
DS2422 Data Alarm Threshold registers (address 020Ah, 020Bh) store values, which determine whether data read through serial interface generate alarm. Such alarm generated input data qualifies alarm alarm signaling enabled. bits EDLA EDHA that enable serial input alarm located DATA_IF Control Register. corresponding alarm flags found Alarm Status Register address 0214h.
DATA_IF Control Register Bitmap
ADDR 0211h EDHA EDLA During mission, there only read access this register. Bits have function. They always read cannot written
DS2422
Register Details
DESCRIPTION EDLA: Enable Data Alarm BIT(S) DEFINITION This controls whether, during mission, Data Alarm Flag set, data value from serial data interface equal lower than value Data Alarm Threshold Register. EDLA data alarms enabled. EDLA data alarms generated. This controls whether, during mission, Data High Alarm Flag set, data value from serial data interface equal higher than value Data High Alarm Threshold Register. EDHA data high alarms enabled. EDHA data high alarms generated.
EDHA: Enable Data High Alarm
REAL-TIME CLOCK CONTROL
minimize power consumption battery-operated datalogger, oscillator should turned when device use. oscillator on/off located control register. This register also includes EHSS bit, which determines whether sample rate specified seconds minutes.
Control Register Bitmap
ADDR 0212h EHSS EOSC During mission, there only read access this register. Bits have function. They always read cannot written
Register Details
DESCRIPTION BIT(S) DEFINITION This controls crystal oscillator RTC. When logic oscillator will start operation. When written logic oscillator stops device low-power data retention mode. This must normal operation. temperature conversion serial data input must attempted while oscillator stopped. This will cause device enter into undefined state, requiring power-on reset restore trim settings recover. This controls speed Sample Rate counter. When logic sample rate specified minutes. When logic sample rate specified seconds.
EOSC: Enable Oscillator
EHSS: Enable High Speed Sample
DS2422
MISSION CONTROL
DS2422 operation writing appropriate data special function registers, which located register pages. settings Mission Control Register determine whether temperature and/or external data logged, which format bits) used whether data overwritten data, once datalog memory full. additional control tell DS2422 wait with logging data until temperature alarm encountered.
Mission Control Register Bitmap
ADDR 0213h SUTA DLFS TLFS During mission, there only read access this register. Bits have function. They always read cannot written
Register Details
DESCRIPTION ETL: Enable Temperature Logging EDL: Enable Data Logging BIT(S) DEFINITION device temperature-logging mission, this must logic successfully start mission, must temperature logging enabled, recorded temperature values will always stored starting address 1000h. device data-logging mission (recording data from serial data interface), this must logic successfully start mission, must only data logging enabled temperature data), recorded data values will stored starting address 1000h. both, temperature data logging enabled, recorded data values will begin address 2000h (TLFS DLFS) 1A00h (TLFS DLFS 2400h (TLFS DLFS This specifies format used store temperature readings datalog memory. this data will stored 8-bit format. this 16-bit format will used (higher resolution). With 16bit format, most-significant byte stored lower address. This specifies format used store data readings from serial data interface datalog memory. this data will stored 8-bit format. this 16-bit format will used (higher resolution). With 16-bit format, most-significant byte stored lower address. This controls whether, during mission, datalog memory overwritten with data whether data logging stopped once datalog memory full. Setting this enables rollover data logging continues beginning, overwriting previously collected data. this logging conversions will stop once datalog memory full. However, will continue will remain until Stop Mission command performed. This specifies whether mission begins immediately (includes delayed start) temperature alarm will required start mission. this device will perform 8-bit temperature conversion selected sample rate begin with data logging only alarming temperature (high alarm alarm) found. first datalog entry will sample period after alarm occurred. Start Upon Temperature Alarm function only available temperature logging enabled (ETL
TLFS: Temperature Logging Format Selection DLFS: Data Logging Format Selection
Rollover Control
SUTA: Start Mission upon Temperature Alarm
DS2422
ALARM STATUS
fastest determine whether programmed alarm threshold exceeded during mission through reading Alarm Status Register. networked environment that contains multiple DS2422-based dataloggers devices that encountered alarm quickly identified means Conditional Search command (see Function Commands). data temperature alarm only occurs enabled (see Temperature Sensor Alarm Serial Input Alarm). alarm always enabled.
Alarm Status Register Bitmap
ADDR 0214h There only read access this register. Bits have function. They always read five alarm status bits cleared simultaneously when Clear Memory function invoked. Memory Control Functions details.
Register Details
DESCRIPTION TLF: Temperature Alarm Flag BIT(S) DEFINITION this reads there least temperature conversion during mission revealing temperature equal lower than value Temperature Alarm Register. forced conversion affect bit. This also with initial alarm SUTA mode. this reads there least temperature conversion during mission revealing temperature equal higher than value Temperature High Alarm Register. forced conversion affect bit. This also with initial alarm SUTA mode. this reads there least data value read from serial data interface during mission revealing value equal lower than value Data Alarm Register. forced conversion affect bit. this reads there least data value read from serial data interface during mission revealing value equal higher than value Data High Alarm Register. forced conversion affect bit. this reads device performed power-on-reset. This occurs when VBAT power source gets first connected assembly when power supply gets interrupted. trim settings need restored proper function. data found datalog memory should disregarded.
THF: Temperature High Alarm Flag
DLF: Data Alarm Flag
DHF: Data High Alarm Flag
BOR: Battery Reset Alarm
GENERAL STATUS
information general status register tells host computer whether mission-related command executed successfully. Individual status bits indicate whether DS2422 performing mission, waiting temperature alarm trigger logging data whether data from latest mission been cleared.
General Status Register Bitmap
ADDR 0215h WFTA MEMCLR There only read access this register. Bits have function.
DS2422
Register Details
DESCRIPTION MIP: Mission Progress BIT(S) DEFINITION this reads device been mission this mission still progress. returns from logic logic when mission ended. function commands Start Mission Stop Mission. this reads Mission Time Stamp, Mission Samples Counter, well alarm flags Alarm Status Register have been cleared preparation mission. Executing Clear Memory command clears these memory sections. MEMCLR will return soon mission started using Start Mission command. memory cleared order mission start. this reads Mission Start upon Temperature Alarm selected Start Mission command successfully executed, device experienced temperature alarm. This cleared after temperature alarm event, affected Clear Memory command. Once set, WFTA remains mission stopped before temperature alarm occurs. clear WFTA manually before starting mission, high temperature alarm (address 0209h) -40°C perform forced conversion.
MEMCLR: Memory Cleared
WFTA: Waiting Temperature Alarm
MISSION START DELAY
content Mission Start Delay Counter tells many minutes will have expire from time mission started until first measurement mission will take place (SUTA until device will start testing temperature temperature alarm (SUTA Mission Start Delay stored unsigned 24-bit integer number. maximum delay 16777215 minutes, equivalent 11650 days roughly years. start delay non-zero SUTA first delay expire before device starts testing temperature alarms begin logging data.
Mission Start Delay Counter
ADDR 0216h Delay Byte 0217h Delay Center Byte 0218h Delay High Byte During mission, there only read access these registers.
typical mission, Mission Start Delay mission long single DS2422 store readings selected sample rate, several devices Mission Start Delay second device start recording soon memory first device full, RO-bit Mission Control Register (address 0213h) must prevent overwriting collected data once datalog memory full.
MISSION TIME STAMP
Mission Time Stamp indicates date time first logged temperature and/or data sample mission. There only read access Mission Time Stamp Register.
Mission Time Stamp Registers Bitmap
ADDR 0219h 021Ah 021Bh 021Ch 021Dh 021Eh CENT 12/24 Years Seconds Minutes
20h. AM/PM
10h.
Single Seconds Single Minutes Single Hours Single Date Single Months Single Years
Date 10m.
DS2422
MISSION PROGRESS INDICATOR
Depending settings Mission Control Register (address 0213h) DS2422 will temperature and/or serial input data 8-bit 16-bit format. description explains where device stores data datalog memory. Mission Samples Counter together with starting address logging format bits) provides information identify valid blocks data that have been gathered during current (MIP latest mission (MIP Datalog Memory Usage illustration.
Mission Samples Counter Register
ADDR 0220h Byte 0221h Center Byte 0222h High Byte There only read access this register. Note that when both internal temperature serial input logging enabled, logs counted event Mission Samples Counter Device Samples Counter. number read from Mission Samples Counter indicates often DS2422 woke during mission measure temperature and/or read data from serial interface. number format 24-bit unsigned integer. Mission Samples Counter reset through Clear Memory command.
OTHER INDICATORS
Device Samples Counter similar Mission Samples Counter. During mission this counter increments whenever DS2422 wakes measure data when device testing temperature alarm SUTA mode. Between missions counter increments whenever Forced Conversion command executed. This Device Samples Counter functions like gauge battery that powers chip.
Device Samples Counter Register
ADDR 0223h 0224h 0225h There only read access this register. Byte Center Byte High Byte
Device Samples Counter reset zero when battery connected VBAT pin. number format 24-bit unsigned integer. maximum number that represented this format 16777215. Device Configuration Byte used allow master distinguish between DS2422 chip different versions iButtons based this chip. With DS2422, this byte always reads 00h.
Device Configuration Byte
ADDR 0226h There only read access this register.
SECURITY PASSWORD
DS2422 designed passwords that control read access full access. Reading from writing scratchpad well forced conversion command does require password. password needs transmitted right after command code memory control function. password checking enabled password transmitted compared passwords stored device. data pattern stored Password Control register determines whether password checking enabled.
DS2422
Password Control Register
ADDR 0227h During mission, there only read access this register.
enable password checking, bits need form binary pattern 10101010 (AAh). default pattern different from AAh. pattern different from AAh, pattern accepted, long length exactly bits. Once enabled, changing passwords disabling password checking requires knowledge current full-access password. Before enabling password checking, passwords read-only access well full access (read/write/control) need written password registers. Setting password enabling/disabling password checking done same writing data memory location, only address different. Since they located same memory page, both passwords redefined same time.
Read Access Password Register
ADDR 0228h 0229h RP15 RP14 RP13 RP12 RP11 RP10 022Eh RP55 RP54 RP53 RP52 RP51 RP50 RP49 RP48 022Fh RP63 RP62 RP61 RP60 RP59 RP58 RP57 RP56 There only write access this register. Attempting read password reports zeros. password cannot changed while mission progress. Read Access Password needs transmitted exactly sequence RP0, RP1. RP62, RP63. This password only applies functions "Read Memory" "Read Memory with CRC". DS2422 delivers requested data only password transmitted master correct password checking enabled.
Full Access Password Register
ADDR 0230h 0231h FP15 FP14 FP13 FP12 FP11 FP10 0236h FP55 FP54 FP53 FP52 FP51 FP50 FP49 FP48 0237h FP63 FP62 FP61 FP60 FP59 FP58 FP57 FP56 There only write access this register. Attempting read password will report zeros. password cannot changed while mission progress. Full Access Password needs transmitted exactly sequence FP0, FP1. FP62, FP63. will affect functions "Read Memory", "Read Memory with CRC", "Copy Scratchpad", "Clear Memory", "Start Mission", "Stop Mission". DS2422 executes command only password transmitted master correct password checking enabled. special behavior write access logic, Password Control Register both passwords must written same time. When setting passwords, always verify (read back) scratchpad before sending copy scratchpad command. After password successfully copied from scratchpad memory location, erase scratchpad filling with data (write scratchpad command). Otherwise copy passwords will remain scratchpad public read access.
DS2422
SERIAL DATA INTERFACE TUNING
serial interface consists several signals that intended control external circuitry, such analog-todigital converter (see Figure 9A). There signal, called CNVST, which used load data into shift register trigger data conversion. delay from activation serial interface (PUMP_ONZ) CNVST user-programmable through Delay Register. When used with charge pump such MAX619, variable delay used give charge pump adequate time stabilize before conversion starts. charge pump used, delay begin conversion sooner.
Delay Register
ADDR 0400h delay value During mission, there only read access this register.
Delay Register holds preset value counter that determines duration tSP. number format unsigned integer with values ranging from decimal). This equivalent range from 127.5ms. power-on value this register 08h.
TEMPERATURE CONVERTER TRIM
DS2422 leaves factory fully tested, trimmed temperature accuracy. actual trim values consist sets, Temperature Counter Reset Temperature Conversion Length, which need determined individually each device during 2-point calibration step. These trim values need written respective registers Trim Register Page before device meets accuracy specification shown graphs this document.
Temperature Counter Reset Register
ADDR 0404h Temperature Counter Reset Byte 0405h Temperature Counter Reset High Byte There always full read/write access this register. Bits High Byte always cannot written power-on default (0404h) (0405h). Temperature Counter Reset value provides purely vertical shift along Temperature Transfer Curve order reset zero point. algorithm determine correct Temperature Counter Reset value included application note that describes 2-point calibration trim.
Temperature Conversion Length Register
ADDR 0406h Temperature Conversion Length Byte 0407h Temp Conversion Length High Byte There always full read/write access this register. Bits High Byte always cannot written power-on default (0406h) (0407h). Temperature Conversion Length value provides vertical horizontal shift Temperature Transfer Curve. algorithm determine correct Temperature Counter Reset value included application note that describes 2-point calibration trim.
DATALOG MEMORY USAGE
Once setup mission, DS2422 logs temperature measurements and/or external data equidistant time points entry after entry datalog memory. datalog memory able store 8192 entries 8-bit format 4096 entries 16-bit format (Figure 10A). temperature well external data logged, both same format, memory split into equal sections that store 4096 8-bit entries 2048 16-bit entries (Figure 10B). device data different formats, temperature 8-bit external data 16-bit format, memory split into blocks different size, accommodating 2560 entries either data source (Figure 10C). this case, upper bytes used. 16-bit format, higher bits entry stored
DS2422 lower address. Knowing starting time point (Mission Time Stamp) interval between temperature measurements reconstruct time date each measurement. There alternatives DS2422 behaves after datalog memory filled with data. user program device either stop further recording (disable "rollover") overwrite previously recorded data (enable "rollover"), entry time, starting again beginning respective memory section. contents Mission Samples Counter conjunction with sample rate Mission Time Stamp will then allow reconstructing time points values stored datalog memory. This gives exact history over time most recent measurements taken. Earlier measurements cannot reconstructed.
Figure 10A. One-Channel Logging
TLFS DLFS 1000h TLFS DLFS 1000h
8192 8-bit entries Temperature External data
4096 16-bit entries Temperature External data
With 16-bit format, most-significant byte stored lower address.
2FFFh
2FFFh
Figure 10B. Two-Channel Logging, Equal Resolution
TLFS DLFS 1000h Temperature 4096 8-bit entries 1FFFh 2000h External Data 4096 8-bit entries 2FFFh External Data 2048 16-bit entries 2FFFh Temperature 2048 16-bit entries 1FFFh 2000h TLFS DLFS 1000h
With 16-bit format, most-significant byte stored lower address.
DS2422
Figure 10C. Two-Channel Logging, Different Resolution
TLFS DLFS Temperature 2560 8-bit entries 1000h 19FFh 1A00h Temperature 2560 16-bit entries 23FFh External Data 2560 8-bit entries (not used) 2400h 2DFFh
2E00h 2FFFh
TLFS DLFS 1000h
External Data 2560 16-bit entries 2DFFh (not used)
2E00h 2FFFh
With 16-bit format, most-significant byte stored lower address.
MISSIONING
typical task DS2422 recording temperature and/or external data. Before device perform this function, needs properly. This procedure called missioning. First all, DS2422 needs have valid time date. This reference time local time, when used inside mobile unit, (also called GMT, Greenwich Mean Time) other time standard that agreed upon. oscillator must running (EOSC memory assigned store Mission Time Stamp, Mission Samples Counter, Sample Rate, Alarm Flags must cleared using Memory Clear command. enable device mission, least enable logging bits needs These general settings that have made case, regardless type object monitored duration mission. alarm signaling desired, temperature alarm and/or data alarm high thresholds must defined. convert temperature value into binary code written threshold registers described under Temperature Conversion earlier this document. Determining thresholds data alarm depends hardware/converter that connected DS2422's serial input. addition, temperature and/or data alarm must enabled low- and/or high-threshold. This makes device respond Conditional Search command (see Function Commands), provided that alarming condition been encountered. setting (rollover enable) sample rate depends duration mission monitoring requirements. most recently logged data important, rollover should enabled Otherwise should estimate duration mission minutes divide number 8192 (single channel 8-bit format) 4096 (single channel 16-bit format, channels 8-bit format) 2048 (two channels 16-bit format) 2560 (two channels, 8-bit format 16-bit format) calculate value sample rate (number minutes between temperature conversions). estimated duration mission days 14400 minutes), example, then 8192-byte capacity datalog memory would sufficient store 8-bit value every minutes (110 seconds). datalog memory DS2422 large enough store readings, several devices Mission Start Delay values that make second device start logging soon memory first device full, RO-bit needs disable rollover that would otherwise overwrite logged data. After Mission Start Delay set, sample rate needs written Sample Rate Register. sample rate value from 16383, coded unsigned 14-bit binary number. sample rate zeros valid must avoided under circumstances. This causes device enter into undefined state, requiring power-on reset restore trim settings recover. fastest sample rate sample second (EHSS Sample Rate 0001h) slowest sample every 273.05 hours (EHSS Sample Rate FFFh). sample every minutes, example, sample rate value needs (EHSS decimal (equivalent 0168h EHSS
DS2422 there risk unauthorized access DS2422 manipulation data, should define passwords read access full access. Before passwords become effective, their needs enabled. Security Password more details. last step begin mission issue Start Mission command. soon received this command, DS2422 sets flag clear MEMCLR flag. With immediate/delayed start mode (SUTA after many minutes specified Mission Start Delay over, device wakes copy current date time mission time stamp register, first entry mission. This increments both Mission Samples Counter Device Samples Counter. subsequent entries made specified value Sample Rate Register EHSS bit. Start Upon Temperature Alarm mode chosen (SUTA DS2422 will first wait until start delay over. Then device wakes intervals specified sample rate EHSS measure temperature. This increments device samples counter only. Only after alarming temperature encountered does DS2422 mission time stamp. first sample mission logged sample period after temperature alarm occurred. From then both Mission Samples Counter Device Samples Counter increments same time. subsequent entries made specified value Sample Rate Register EHSS bit. general-purpose memory operates independently other memory sections write-protected during mission. memory DS2422 read time, watch progress mission. Attempts read passwords will read bytes instead data that stored password registers.
ADDRESS REGISTERS TRANSFER STATUS
Because serial data transfer, DS2422 employs three address registers, called TA1, TA2, (Figure 11). Registers must loaded with target address which data written from which data sent master upon Read command. Register acts like byte counter transfer status register. used verify data integrity with Write commands. Therefore, master only read access this register. lower bits Register indicate address last byte that been written scratchpad. This address called Ending Offset. DS2422 requires that Ending Offset always Copy Scratchpad function. Register, called "partial byte flag," number data bits sent master integer multiple always Note that lowest bits target address also determine address within scratchpad, where intermediate storage data will begin. This address called byte offset. target address Write command 13Ch, example, then scratchpad will store incoming data beginning byte offset will full after only bytes. corresponding ending offset this example 1Fh. best economy speed efficiency, target address writing should point beginning page, i.e., byte offset will Thus full 32-byte capacity scratchpad available, resulting also ending offset 1Fh. However, possible write several contiguous bytes somewhere within page. ending offset together with Partial Overflow Flag mainly means support master checking data integrity after Write command. highest valued Register, called Authorization Accepted, indicates that valid copy command scratchpad been received executed. Writing data scratchpad clears this flag.
Figure Address Registers
Target Address (TA1)
Target Address (TA2) Ending Address with Data Status (E/S) (Read Only)
DS2422
WRITING WITH VERIFICATION
write data DS2422, scratchpad used intermediate storage. First master issues Write Scratchpad command specify desired target address, followed data written scratchpad. next step, master sends Read Scratchpad command read scratchpad verify data integrity. preamble scratchpad data, DS2422 sends requested target address contents Register. flag set, data arrive correctly scratchpad. master does need continue reading; start trial write data scratchpad. Similarly, flag indicates that Write command recognized device. everything went correctly, both flags cleared ending offset indicates address last byte written scratchpad. master continue verifying every data bit. After master verified data, send Copy Scratchpad command. This command must followed exactly data three address registers TA1, master read them verifying scratchpad. soon DS2422 received these bytes, will copy data requested location beginning target address.
MEMORY- CONTROL-FUNCTION COMMANDS
"Memory/Control Function Flow Chart" (Figure describes protocols necessary accessing memory special function registers DS2422. example these other functions DS2422 mission included this document, preceding Electrical Characteristics section. communication between master DS2422 takes place either regular speed (default, Overdrive Speed explicitly into Overdrive Mode DS2422 assumes regular speed. Internal memory access during mission priority over external access through 1-Wire interface. This affects several commands described below. section Memory Access Conflicts details remedies.
WRITE SCRATCHPAD COMMAND [0Fh]
After issuing Write Scratchpad command, master must first provide 2-byte target address, followed data written scratchpad. data written scratchpad starting byte offset (T4:T0). master send many bytes needed reach Ending Offset 1Fh. data byte incomplete, content ignored partial byte flag set. When executing Write Scratchpad command generator inside DS2422 (see Figure calculates entire data stream, starting command code ending last data byte sent master. This generated using CRC16 polynomial first clearing generator then shifting command code (0Fh) Write Scratchpad command, Target Addresses supplied master data bytes. master Write Scratchpad command time. ending offset 11111b, master send read-time slots receives inverted CRC16 generated DS2422. Note that both register pages write-protected during mission. Although Write Scratchpad command works normally time, subsequent copy scratchpad register page will fail during mission.
READ SCRATCHPAD COMMAND [AAh]
This command used verify scratchpad data target address. After issuing Read Scratchpad command, master begins reading. first bytes will target address. next byte will ending offset/data status byte (E/S) followed scratchpad data beginning byte offset (T4:T0), shown Figure master continue reading data until scratchpad after which will receive inverted CRC16 command code, Target Addresses TA2, byte, scratchpad data starting target address. After read, master will read logical from DS2422 until reset pulse issued.
DS2422
COPY SCRATCHPAD WITH PASSWORD [99h]
This command used copy data from scratchpad writable memory sections. After issuing Copy Scratchpad command, master must provide 3-byte authorization pattern, which obtained reading scratchpad verification. This pattern must exactly match data contained three address registers (TA1, TA2, E/S, that order). Next master must transmit 64-bit full-access password. passwords enabled transmitted password different from stored full-access password, Copy Scratchpad with Password command will fail. device will stop communicating will wait reset pulse. password correct passwords were enabled, device will test 3-byte authorization code. authorization code pattern matches, (Authorization Accepted) flag will copy will begin. pattern alternating will transmitted after data been copied until master issues reset pulse. While copy progress attempt reset part will ignored. Copy typically takes byte. data copied determined three address registers. scratchpad data from beginning offset through ending offset will copied, starting target address. Anywhere from bytes copied memory with this command. flag will remain logic until cleared next Write Scratchpad command. With suitable password, copy scratchpad will always function pages data memory pages calibration memory. While mission progress, write attempts register pages will successful. (Authorization Accepted) remaining will indicate this.
READ MEMORY WITH PASSWORD [69h]
Read Memory with command general function read from device. This command generates transmits 16-bit following last data byte memory page. After having sent command code Read Memory with command, master sends 2-byte address that indicates starting byte location. Next master must transmit 64-bit passwords. passwords enabled transmitted password does match stored passwords, Read Memory with Password command will fail. device will stop communicating will wait reset pulse. password correct passwords were enabled, master reads data from DS2422 beginning from starting address continuing until 32-byte page reached. that point master will send additional read data time slots receive inverted 16-bit CRC. With subsequent read data time slots master will receive data starting beginning next memory page followed again that page. This sequence will continue until master resets device. When trying read passwords memory areas that marked "reserved", DS2422 will transmit bytes respectively. 32-byte memory page based data transmitted. With initial pass through Read Memory with flow, 16-bit value result shifting command byte into cleared generator followed address bytes contents data memory. Subsequent passes through Read Memory with flow will generate 16-bit that result clearing generator then shifting contents data memory page. After 16-bit last page read, master will receive logical from DS2422 until reset pulse issued. Read Memory with command sequence ended point issuing reset pulse.
DS2422
Figure 12-1. Memory/Control Function Flow Chart
Master Memory Control Fkt. Command Write Scratchpad Master (T7:T0) Master (T15:T8) DS2422 sets Scratchpad Offset (T4:T0) Clears (PF, Master Data Byte Scratchpad Offset DS2422 sets (E4:E0) Scratchpad Offset DS2422 Increments Scratchpad Offset From Functions Flow Chart (Figure Read Scratchpad Master (T7:T0) Master (T15:T8) Master Ending Offset with Data Status (E/S) DS2422 sets Scratchpad Offset (T4:T0) Master Data Byte from Scratchpad Offset Figure Part
Master Reset? DS2422 Increments Scratchpad Offset Scratchpad Offset 11111b? Master Reset?
Master Reset? Scratchpad Offset 11111b?
Partial Byte Written?
Master CRC16 Command, Address Data, Byte, Data Starting Target Address
Master CRC16 Command, Address Data
Master Reset? Master "1"s
Master Reset? Master "1"s
From Figure Part
Functions Flow Chart (Figure
DS2422
Figure 12-2. Memory/Control Function Flow Chart
From Figure Part
Copy Scrpd. [w/PW] Master (T7:T0), (T15:T8) Master Byte Master 64-Bits [Password]
Figure Part
Authorization Code
Password Accepted? Authorization Code Match?
DS2422 Copies Scratchpad Data Memory
Master "1"s Copying Finished DS2422
Master "1"s
Master Reset?
Master Reset? DS2422
Figure Part
Master Reset?
From Figure Part
DS2422
Figure 12-3. Memory/Control Function Flow Chart
From Figure Part
Read Mem. [w/PW]&CRC Master (T7:T0), (T15:T8) Master 64-Bits [Password]
Figure Part
Decision made DS2422
Password Accepted? Decision made Master DS2422 sets Memory Address (T15:T0) Master Data Byte from Memory Address
Master Reset? Page? Master CRC16 Command, Address, Data Pass); CRC16 Data (Subsequent Passes)
DS2422 Increments Address Counter
Master Reset
Memory? Master Reset? Master "1"s From Figure Part
Figure Part
DS2422
Figure 12-4. Memory/Control Function Flow Chart
From Figure Part
Clear Mem. [w/PW] Master 64-Bits [Password] Master dummy byte
Forced Conversion? Master dummy byte
Figure Part
Mission Progress? DS2422 Performs Temp. Conversion DS2422 copies Result Address 020C/Dh DS2422 Reads Serial Data Interface DS2422 copies Result Address 020E/Fh
Password Accepted? Mission Progress? DS2422 clears Mission Time Stamp, Mission Samples Counter, Alarm Flags
DS2422 sets MEMCLR
Master Reset?
Master Reset?
Figure Part
From Figure Part
DS2422
Figure 12-5. Memory/Control Function Flow Chart
From Figure Part
Start Mission [w/PW] Master 64-Bits [Password] Master dummy byte
Mission Start Delay Process
Stop Mission [w/PW] Master 64-Bits [Password] Start Delay Counter Master dummy byte
Password Accepted?
DS2422 Waits Minute DS2422 decrements Start Delay Counter
Password Accepted?
Mission Progress?
SUTA
Mission Progress? DS2422 sets WFTA
DS2422 Sets WFTA=1 MEMCLR DS2422 sets MEMCLR DS2422 Initiates Mission Start Delay Process DS2422 Waits Sample Period DS2422 Performs 8-bit Temp. Conversion Temp. Alarm? DS2422 sets WFTA=0 DS2422 Waits Sample Period DS2422 copies Data Mission Time Stamp Register
Master Reset?
Figure Part
Master Reset?
DS2422 Starts Logging Taking First Sample Process
DS2422
CLEAR MEMORY WITH PASSWORD [96h]
Clear Memory with Password command used prepare device another mission. This command will only executed mission progress. After command code master must transmit 64-bit fullaccess password followed dummy byte. passwords enabled transmitted password different from stored full-access password mission progress, Clear Memory with Password command will fail. device will stop communicating will wait reset pulse. password correct passwords were enabled, device will clear Mission Time Stamp, Mission Samples Counter, Sample Rate register, alarm flags Alarm Status Register. After these cells cleared, MEMCLR General Status Register will read indicate successful execution Clear Memory with Password command. Clearing datalog memory necessary because Mission Samples Counter indicates many entries datalog memory valid.
FORCED CONVERSION [55h]
Forced Conversion command used measure temperature read data from serial data interface without starting mission. After command code master send byte conversion started. conversion result found 16-bit value Latest Temperature Conversion Result Latest Serial Data Reading registers. This command only executed mission progress (MIP cannot interrupted takes maximum complete. During this time memory access through 1Wire interface blocked. device will behave same during mission when sampling interferes with memory/control function command. Memory Access Conflicts details. forced conversion must attempted while oscillator stopped. This causes device enter into undefined state, requiring power-on reset restore trim settings recover.
START MISSION WITH PASSWORD [CCh]
DS2422 uses control function command start mission. mission only started previous mission been ended memory been cleared. After command code, master must transmit 64-bit full-access password followed dummy byte. passwords enabled transmitted password different from stored full-access password mission progress, Start Mission with Password command will fail. device will stop communicating will wait reset pulse. password correct passwords were enabled, device will start mission. sampling data logging will begin soon mission start delay over (SUTA and, SUTA sample period after temperature alarm encountered. While device waiting temperature alarm occur, WFTA flag general status register will read During mission there only read access Register Pages.
STOP MISSION WITH PASSWORD [33h]
DS2422 uses control function command stop mission. Only mission that progress stopped. After command code, master must transmit 64-bit full-access password followed dummy byte. passwords enabled transmitted password different from stored full-access password mission progress, Stop Mission with Password command will fail. device will stop communicating will wait reset pulse. password correct passwords were enabled, device will clear General Status Register restore write access Register Pages. WFTA cleared. description General Status Register method clear WFTA bit.
MEMORY ACCESS CONFLICTS
While mission progress while device waiting temperature alarm start mission, periodically temperature sample taken and/or data read from serial interface logged. This "internal activity" priority over 1-Wire communication. consequence, device-specific commands (excluding function commands 1-Wire reset) will perform properly when internal "external" activities interfere with each other. affected commands Start Mission, Forced Conversion Clear Memory, because they applicable while mission progress while device waiting temperature alarm. table below explains remaining five commands affected internal activity, detect this interference work around
DS2422 COMMAND INDICATION INTERFERENCE CRC16 command flow reads FFFFh. data read changes bytes bytes received FFh, including command flow. device behaves Authorization Code password valid copy function would end. data read changes bytes bytes received FFh, including command flow, despite valid password. general Status register address 215h reads while bits REMEDY Wait seconds, 1-Wire reset, address device, repeat Write Scratchpad with same data check validity CRC16 command flow. Alternatively, Read Scratchpad verify data integrity. Wait seconds, 1-Wire reset, address device, repeat Read Scratchpad check validity CRC16 command flow. Wait seconds, 1-Wire reset, address device, issue Read Scratchpad check AA-bit byte. AA-bit set, Copy Scratchpad successful. Wait seconds, 1-Wire reset, address device, repeat Read Memory with check validity CRC16 memory page. Wait seconds, 1-Wire reset, address device, repeat Stop Mission. Perform 1-Wire reset, address device, read general Status register address 215h check MIP-bit. MIP-bit Stop Mission successful.
Write Scratchpad
Read Scratchpad
Copy Scratchpad
Read Memory with
Stop Mission
interference more likely seen with high sample rate sample every second) with high-resolution logging, which last 666ms when both temperature external data recorded. With lower sample rates interference hardly visible all. case, when writing driver software, important know about possibility interference take measures work around
1-Wire SYSTEM
1-Wire system, which single master more slaves. instances DS2422 slave device. master typically microcontroller. discussion this system broken down into three topics: hardware configuration, transaction sequence, 1-Wire signaling (signal types timing). 1-Wire protocol defines transactions terms state during specific time slots that initiated falling edge sync pulses from master. more detailed protocol description, refer Chapter Book DS19xx iButton Standards.
HARDWARE CONFIGURATION
1-Wire only single line definition; important that each device able drive appropriate time. facilitate this, each device attached 1-Wire must have open drain tri-state outputs. 1-Wire port DS2422 open-drain with internal circuit equivalent that shown Figure multidrop consists 1-Wire with multiple slaves attached. standard speed 1-Wire maximum data rate 16.3kbps. speed boosted 142kbps activating Overdrive mode. DS2422 guaranteed fully compliant iButton Standard. maximum data rate standard speed mode 15.4kbps 125kbps Overdrive. value pullup resistor primarily depends network size load conditions. DS2422 requires pullup resistor maximum 2.2k speed. idle state 1-Wire high. reason transaction needs suspended, MUST left idle state transaction resume. this does occur left more than 16µs (Overdrive speed) more than 120µs (standard speed), more devices reset. Note that DS2422 does quite meet full 16µs maximum time normal 1-Wire Overdrive timing. With DS2422 must left longer than 12µs Overdrive ensure that DS2422 1-Wire
DS2422 performs reset. DS2422 will communicate properly when used conjunction with DS2480B DS2490 1-Wire driver adapters that based these driver chips.
Figure Hardware Configuration
MASTER VPUP RPUP DATA Typ. MOSFET DS2422 1-Wire PORT
Open Drain Port
RECEIVE TRANSMIT
TRANSACTION SEQUENCE
protocol accessing DS2422 through 1-Wire port follows: Initialization Function Command Memory/Control Function Command Transaction/Data
INITIALIZATION
transactions 1-Wire begin with initialization sequence. initialization sequence consists reset pulse transmitted master followed presence pulse(s) transmitted slave(s). presence pulse lets master know that DS2422 ready operate. more details, 1-Wire Signaling section.
DS2422
1-Wire FUNCTION COMMANDS
Once master detected presence, issue eight function commands that DS2422 supports. function commands bits long. list these commands follows (refer flowchart Figure 14).
READ [33h]
This command allows master read DS2422's 8-bit family code, unique 48-bit serial number, 8-bit CRC. This command only used there single slave bus. more than slave present bus, data collision will occur when slaves transmit same time (open drain will produce wiredAND result). resultant family code 48-bit serial number will result mismatch CRC.
MATCH [55h]
Match command, followed 64-bit sequence, allows master address specific DS2422 multidrop bus. Only DS2422 that exactly matches 64-bit sequence will respond following memory function command. other slaves will wait reset pulse. This command used with single multiple devices bus.
SEARCH [F0h]
When system initially brought master might know number devices 1-Wire their registration numbers. taking advantage wired-AND property bus, master process elimination identify registration numbers slave devices. each registration number, starting with least significant bit, master issues triplet time slots. first slot, each slave device participating search outputs true value registration number bit. second slot, each slave device participating search outputs complemented value registration number bit. third slot, master writes true value selected. slave devices that match written master stop participating search. both read bits zero, master knows that slave devices exist with both states bit. choosing which state write, master branches romcode tree. After complete pass, master knows registration number single device. Additional passes identify registration numbers remaining devices. Refer Application Note 187: 1-Wire Search Algorithm detailed discussion, including example.
CONDITIONAL SEARCH [ECh]
Conditional Search command operates similarly Search command except that only those devices, which fulfill certain conditions, will participate search. This function provides efficient means master identify devices multidrop system that have signal important event. After each pass conditional search that successfully determined 64-bit code specific device multidrop bus, that particular device individually accessed Match been issued, since other devices will have dropped search process will waiting reset pulse. DS2422 will respond conditional search five alarm flags Alarm Status Register (address 0214h) reads data temperature alarm will only occur enabled (see Temperature Sensor Alarm Serial Input Alarm). alarm always enabled. first alarm that occurs will make device respond Conditional Search command.
SKIP [CCh]
This command save time single-drop system allowing master access memory functions without providing 64-bit code. more than slave present and, example, Read command issued following Skip command, data collision will occur multiple slaves transmit simultaneously (open drain pulldowns will produce wired-AND result).
RESUME COMMAND [A5h]
DS2422 needs accessed several times before mission will start. multidrop environment this means that 64-bit code after Match command repeated every access. maximize data throughput multidrop environment, Resume function implemented. This function checks status and, set, directly transfers control Memory/Control functions, similar Skip
DS2422 command. only through successfully executing Match ROM, Search Overdrive Match command. Once set, device repeatedly accessed through Resume Command function. Accessing another device will clear bit, preventing more devices from simultaneously responding Resume Command function.
OVERDRIVE SKIP [3Ch]
single-drop this command save time allowing master access memory/control functions without providing 64-bit code. Unlike normal Skip command, Overdrive Skip sets DS2422 Overdrive mode communication following this command occur Overdrive speed until reset pulse minimum 690µs duration resets devices standard speed When issued multidrop this command will Overdrive-supporting devices into Overdrive mode. subsequently address specific Overdrive-supporting device, reset pulse Overdrive speed issued followed Match Search command sequence. This will speed time search process. more than slave supporting Overdrive present Overdrive Skip command followed Read command, data collision will occur multiple slaves transmit simultaneously (opendrain pulldowns will produce wired-AND result).
OVERDRIVE MATCH [69h]
Overdrive Match command followed 64-bit sequence transmitted Overdrive Speed allows master address specific DS2422 multidrop simultaneously Overdrive mode. Only DS2422 that exactly matches 64-bit sequence will respond subsequent memory/control function command. Slaves already Overdrive mode from previous Overdrive Skip successful Overdrive Match command will remain Overdrive mode. overdrive-capable slaves will return standard speed next Reset Pulse minimum 690µs duration. Overdrive Match command used with single multiple devices bus.
DS2422
Figure 14-1. Functions Flow Chart
From Memory Functions Flow Chart (Figure Master Reset Pulse Reset Pulse? Master Function Command Read Command? DS2422 Presence Pulse Match Command? Search Command? Figure Part From Figure
Part
Cond. Search Command?
Condition Met?
DS2422 Family Code Byte)
Master
DS2422 DS2422 Master Match? DS2422 DS2422 Master Match? DS2422 DS2422 Master Match?
DS2422 DS2422 Master Match? DS2422 DS2422 Master Match? DS2422 DS2422 Master Match? Figure Part From Figure Part
Match? DS2422 Serial Number Bytes)
Master
Match? DS2422 Byte Master
Match?
Memory Functions Flow Chart (Figure
DS2422
Figure 14-2. Functions Flow Chart
Figure Part
From Figure Part Skip Command? Resume Command? Overdrive Skip ROM? Overdrive Match ROM?
Master Master Master
Master Reset
Match?
Master Reset
Match?
Match? From Figure Part Figure Part
DS2422
1-Wire SIGNALING
DS2422 requires strict protocols ensure data integrity. protocol consists four types signaling line: Reset Sequence with Reset Pulse Presence Pulse, Write-Zero, Write-One Read-Data. Except presence pulse master initiates these signals. DS2422 communicate different speeds, standard speed, Overdrive Speed. explicitly into Overdrive mode, DS2422 will communicate standard speed. While Overdrive Mode fast timing applies waveforms. from idle active, voltage 1-Wire line needs fall from VPUP below threshold VTL. from active idle, voltage needs rise from VILMAX past threshold VTH. time takes voltage make this rise seen Figure duration depends pull-up resistor (RPUP) used capacitance 1-Wire network attached. voltage VILMAX relevant DS2422 when determining logical level, triggering events. initialization sequence required begin communication with DS2422 shown Figure Reset Pulse followed Presence Pulse indicates DS2422 ready receive data, given correct memory function command. master uses slew-rate control falling edge, must pull down line tRSTL compensate edge. tRSTL duration 690µs longer will exit Overdrive Mode returning device standard speed. DS2422 Overdrive Mode tRSTL longer than 80µs device will remain Overdrive Mode.
Figure Initialization Procedure "Reset Presence Pulses"
MASTER "RESET PULSE" MASTER "PRESENCE PULSE" VPUP tMSP
VIHMASTER VILMAX
tRSTL
tPDH MASTER
tPDL tRSTH
tREC DS2422
RESISTOR
After master released line goes into receive mode (RX). 1-Wire pulled VPUP through pullup resistor case DS2480B driver, active circuitry. When threshold crossed, DS2422 waits tPDH then transmits Presence Pulse pulling line tPDL. detect presence pulse, master must test logical state 1-Wire line tMSP. tRSTH window must least tPDHMAX, tPDLMAX, tRECMIN. Immediately after tRSTH expired, DS2422 ready data communication. mixed population network tRSTH should extended minimum 480µs standard speed 48µs Overdrive speed accommodate other 1-Wire devices.
Read/Write Time Slots
Data communication with DS2422 takes place time slots, which carry single each. Write time slots transport data from master slave. Read time slots transfer data from slave master. definitions write read time slots illustrated Figure communication begins with master pulling data line low. voltage 1-Wire line falls below threshold VTL, DS2422 starts internal timing generator that determines when data line will sampled during write time slot long data will valid during read time slot.
DS2422
Master-to-Slave
write-one time slot, voltage data line must have crossed threshold before write-one time tW1LMAX expired. write-zero time slot, voltage data line must stay below threshold until write-zero time tW0LMIN expired. most reliable communication voltage data line should exceed VILMAX during entire tW0L tW1L window. After threshold been crossed, DS2422 needs recovery time tREC before ready next time slot.
Figure Read/Write Timing Diagram Write-One Time Slot
VPUP VIHMASTER VILMAX tW1L
RESISTOR
tSLOT MASTER
Write-Zero Time Slot
VIHMASTER VILMAX VPUP tW0L
RESISTOR
tSLOT MASTER
tREC
Read-Data Time Slot
VIHMASTER VILMAX VPUP tMSR Master Sampling Window RESISTOR tREC tSLOT MASTER DS2422
Slave-to-Master
read-data time slot begins like write-one time slot. voltage data line must remain below until read time expired. During window, when responding with DS2422 will start pulling data line low; internal timing generator determines when this pulldown ends voltage starts rising again. When responding with DS2422 will hold data line all, voltage starts rising soon over.
DS2422 (rise rime) side internal timing generator DS2422 other side define master sampling window (tMSRMIN tMSRMAX) which master must perform read from data line. most reliable communication, should short permissible master should read close later than tMSRMAX. After reading from data line, master must wait until tSLOT expired. This guarantees sufficient recovery time tREC DS2422 ready next time slot.
IMPROVED NETWORK BEHAVIOR
1-Wire environment line termination possible only during transients controlled master (1-Wire driver). 1-Wire networks, therefore, susceptible noise various origins. Depending physical size topology network, reflections from points branch points cancel each other some extent. Such reflections visible glitches ringing 1-Wire communication line. Noise coupled onto 1-Wire line from external sources also result signal glitching. glitch during rising edge time slot cause slave device lose synchronization with master and, consequence, result search command coming dead cause device-specific function command abort. better performance network applications, DS2422 uses 1-Wire front end, which makes less sensitive noise also reduces magnitude noise injected slave device itself. 1-Wire front DS2422 differs from traditional slave devices four characteristics. falling edge presence pulse controlled slew rate. This provides better match line impedance than digitally switched transistor, converting high frequency ringing known from traditional devices into smoother low-bandwidth transition. slew rate control specified parameter tFPD, which different values standard Overdrive speed. There additional low-pass filtering circuit that detects falling edge beginning time slot. This reduces sensitivity high-frequency noise. This additional filtering does apply Overdrive speed. There hysteresis low-to-high switching threshold VTH. negative glitch crosses doesn't below VHY, will recognized (Figure Case hysteresis effective 1-Wire speed. There time window specified rising edge hold-off time tREH during which glitches will ignored, even they extend below threshold (Figure Case tREH). Deep voltage droops glitches that appear late after crossing threshold extend beyond tREH window cannot filtered will taken beginning time slot (Figure Case tREH). Only devices which have parameters tFPD, tREH specified their electrical characteristics improved 1-Wire front end.
Figure Noise Suppression Scheme
VPUP Case Case Case tREH tREH
GENERATION
With DS2422 there different types CRCs (Cyclic Redundancy Checks). 8-bit type stored most significant byte 64-bit ROM. master compute value from first bits 64-bit compare value stored within DS2422 determine data been received error-free. equivalent polynomial function this This 8-bit received true (non-inverted) form. computed factory lasered into ROM. other 16-bit type, generated according standardized CRC16-polynomial function This used error detection when reading register pages datalog memory using Read Memory with command fast verification data transfer when writing reading from scratchpad. contrast 8-bit CRC, 16-bit always communicated inverted form. CRCgenerator inside DS2422 chip (Figure will calculate 16-bit shown command flow chart Figure master compares value read from device calculates from data
DS2422 decides whether continue with operation reread portion data with error. With initial pass through Read Memory with flow chart, 16-bit value result shifting command byte into cleared generator, followed address bytes data bytes. password excluded from calculation. Subsequent passes through Read Memory with flow chart will generate 16-bit that result clearing generator then shifting data bytes. With Write Scratchpad command generated first clearing generator then shifting command code, Target Addresses data bytes. DS2422 will transmit this only data bytes written scratchpad include scratchpad ending offset 11111b. data start location within scratchpad. With Read Scratchpad command generated first clearing generator then shifting command code, Target Addresses TA2, byte, scratchpad data starting target address. DS2422 will transmit this only reading continues through scratchpad, regardless actual ending offset. more information generating values Application Note
Figure CRC-16 Hardware Description Polynomial
Polynomial
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
STAGE
INPUT DATA
OUTPUT
Figure Crystal Placement
Guard ring signal plane
AGND Crystal Crystal
Local ground plane beneath signal plane other side
ALARM
DS2422
COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL-LEGEND
SYMBOL Select TA-E/S <data EOS> <data EOP> <data EOM> <PW/dummy> bytes> <data> CRC16\ loop loop DESCRIPTION 1-Wire Reset Pulse generated master 1-Wire Presence Pulse generated slave Command data satisfy function protocol Command "Write Scratchpad" Command "Read Scratchpad" Command "Copy Scratchpad with Password" Command "Read Memory with Password" Command "Read Memory with Password CRC" Command "Clear Memory with Password Command "Forced Conversion" Command "Start Mission with Password" Command "Stop Mission with Password" Target Address TA1, Target Address TA1, with byte Transfer many data bytes needed reach scratchpad offset Transfer many data bytes needed reach memory page Transfer many data bytes needed reach datalog memory Transfer bytes that either represent valid password acceptable dummy data Transfer bytes Transfer undetermined amount data Transmission byte Transfer inverted CRC16 Indefinite loop where master reads bytes Indefinite loop where master reads bytes
COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL-COLOR CODES
Master slave Slave master
WRITE SCRATCHPAD, REACHING SCRATCHPAD (CANNOT FAIL)
Select <data EOS> CRC16\ loop
READ SCRATCHPAD (CANNOT FAIL)
Select TA-E/S <data EOS> CRC16\ loop
DS2422
COPY SCRATCHPAD WITH PASSWORD (SUCCESS)
Select TA-E/S <PW/dummy> loop
COPY SCRATCHPAD WITH PASSWORD (INVALID TA-E/S PASSWORD)
Select TA-E/S <PW/dummy> loop
READ MEMORY WITH PASSWORD (SUCCESS)
Select <PW/dummy> <data EOP> CRC16\ CRC16\ loop Loop
bytes>
READ MEMORY WITH PASSWORD (INVALID PASSWORD ADDRESS)
Select <PW/dummy> loop
CLEAR MEMORY WITH PASSWORD
Select <PW/dummy> loop
verify success, read General Status Register address 0215h. MEMCLR command executed successfully.
FORCED CONVERSION
Select loop
read result verify success, read addresses 020Ch 020Fh (results) Device Samples Counter address 0223h 0225h. count incremented, command executed successfully.
START MISSION WITH PASSWORD
Select <PW/dummy> loop
verify success, read General Status Register address 0215h. MEMCLR command executed successfully.
DS2422
STOP MISSION WITH PASSWORD
Select <PW/dummy> loop
verify success, read General Status Register address 0215h. command executed successfully.
MISSION EXAMPLE: PREPARE START MISSION
Assumption: previous mission been ended using Stop Mission command. Passwords enabled. Starting mission with DS2422 requires three steps: Step clear data previous mission Step write setup data register page Step start mission
STEP
Clear previous mission. With only single DS2422 connected master, communication step looks like this: MASTER MODE DATA (LSB FIRST) (Reset) (Presence) bytes> (Reset) (Presence) COMMENTS Reset pulse Presence pulse Issue "skip ROM" command Issue "clear memory" command Send dummy password Send dummy byte Reset pulse Presence pulse
DS2422
STEP
During setup, device needs learn following information: Time Date Sample Rate Alarm Thresholds Alarm Controls (Response Conditional Search) General Mission Parameters channels logging format, rollover, start mode) Mission Start Delay following data will setup DS2422 mission that logs temperature using 8-bit format. Such mission could last days until 8192-byte datalog memory full. ADDRESS 0200h 0201h 0202h 0203h 0204h 0205h 0206h 0207h 0208h 0209h 020Ah 020Bh 020Ch 020Dh 020Eh 020Fh 0210h 0211h 0212h 0213h 0214h 0215h 0216h 0217h 0218h DATA EXAMPLE VALUES 15:30:00 hours Time FUNCTION
April 2002 Every minutes (EHSS 10°C high (Don't care)
Date Sample rate Temperature Alarm Threshold External Data Alarm Threshold Clock through read-only registers Temp. Alarm Control Data Alarm Control Oscillator Control, sample rate selection General Mission Control Clock through read-only registers Mission Start Delay
(Don't care) Enable high alarm Disabled (enabled), EHSS (low sample rate) Normal start; rollover; 8-bit temp. (Don't care) minutes
With only single DS2422 connected master, communication step looks like this: MASTER MODE DATA (LSB FIRST) (Reset) (Presence) data bytes> COMMENTS Reset pulse Presence pulse Issue "skip ROM" command Issue "write scratchpad" command TA1, beginning offset=00h TA2, address=0200h Write bytes data scratchpad
MASTER MODE
DATA (LSB FIRST) bytes> (Reset) (Presence) data bytes> (Reset) (Presence) bytes> (Reset) (Presence)
DS2422 COMMENTS Write through scratchpad Reset pulse Presence pulse Issue "skip ROM" command Issue "read scratchpad" command Read TA1, beginning offset=00h Read TA2, address=0200h Read E/S, ending offset=1Fh, flags=0h Read scratchpad data verify Reset pulse Presence pulse Issue "skip ROM" command Issue "copy scratchpad" command (AUTHORIZATION CODE) Send dummy password Reset pulse Presence pulse
STEP
Start mission. With only single DS2422 connected master, communication step looks like this: MASTER MODE DATA (LSB FIRST) (Reset) (Presence) bytes> (Reset) (Presence) COMMENTS Reset pulse Presence pulse Issue "skip ROM" command Issue "start mission" command Send dummy password Send dummy byte Reset pulse Presence pulse
step successful, General Status Register will MEMCLR will mission start delay will count down.
PACKAGE INFORMATION
(The package drawing(s) this data sheet reflect most current specifications. latest package outline information, www.maxim-ic.com/packages.)
DS2422
REVISION HISTORY
REVISION DATE 11/03 8/09 DESCRIPTION Initial release. Added plus sign Ordering Information table reflect this product's conversion lead-free device. PAGES CHANGED
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