DS2490 1-Wire Bridge Chip Communicates regular overdrive 1Wire® s

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

DS2490 1-Wire Bridge Chip Communicates regular overdrive 1Wire® s

Datasheet Thumbnail

Top Searches for this datasheet

19-4993; 10/09
DS2490 1-Wire Bridge Chip
Communicates regular overdrive 1Wire® speeds Supports stiff pullup EEPROM, sensors, crypto iButton® Slew rate controlled 1-Wire timing active pullup accommodate long 1-Wire network lines reduce radiation Programmable 1-Wire timing driver characteristics accommodate wide range 1-Wire network configurations Low- high-level command types, including macros, generating 1-Wire communication Crystal oscillator timebase provides precision timed 1-Wire waveforms High-speed 12Mbps Universal Serial (USB) interface Integrated USB-compliant transceiver Supports remote wake-up from 1-Wire device event resume suspended host system +70oC operating temperature range
ASSIGNMENT
PMOD SUSO 1-WIRE
24-Pin View (300-mil)
ORDERING INFORMATION
PART NUMBER DS2490S+ TEMP RANGE +70oC
PIN-PACKAGE (300 mil)
DS2490S+T&R (300mil) Denotes lead(Pb)-free/RoHS-compliant package. Tape reel.
DESCRIPTION
DS2490 bridge chip that enables communication between host system 1-Wire bus. provides regular, overdrive, flexible 1-Wire communication speeds full-speed 12Mbps connection USB. vendor-specific commands defined this specification used control DS2490 communicate with attached 1-Wire devices. functional block diagram DS2490 shown Figure
1-Wire iButton registered trademarks Maxim Integrated Products, Inc.
DS2490
SIGNAL SUMMARY Table
SIGNAL NAME D1-Wire PMOD
SUSO
TYPE
FUNCTION Power supply input digital 1-Wire functions. Range: Second supply, must tied externally (the pins tied together inside package). Power supply input functions. Range: 3.3V supply regulated from supplied VBUS. data-non-inverted differential data pair. data-inverted signal differential data pair. 1-Wire input/output. Reserved future use. Must tied GND. Suspend Output-buffered suspend-state output from device controller. When HIGH active non-suspended state, when entered suspended state. This open drain output requires external pullup. Crystal input. 12.0 MHz, fundamental-mode, parallel-resonant crystal. 12.0MHz CMOS clock source also used. Crystal output. Connect other side crystal used. Ground reference ground return 1-Wire bus. connect. factory reserved, connect these pins.
RELATED DOCUMENTS
This specification uses terms from references complies with Universal Serial Specification v1.1, which obtained from Implementers Forum website: www.usb.org. specification considered part DS2490 specification.
DOCUMENT ORGANIZATION
remainder this document organized into following major sections: SECTION OVERVIEW 1-WIRE CONTROLLER COMMUNICATION MODE COMMANDS CONTROL COMMANDS COMMUNICATION COMMANDS DEVICE FEEDBACK TRANSCEIVER OSCILLATOR SUSPEND OUTPUT SUMMARY Device functional summary application examples Edge control timing diagrams 1-Wire signals Configuration model, core vendor-specific command summaries Commands used configure 1-Wire interface operational characteristics Commands used control 1-Wire communication command processing Commands used communicate with attached 1-Wire device Technique obtain device status information Transceiver connection requirements Oscillator connection requirements SUSO signal operation purpose
DS2490
SECTION ELECTRICAL CHARACTERISTICS APPLICATION INFORMATION APPENDIX APPENDIX APPENDIX APPENDIX
SUMMARY specifications application example CONTROL COMMANDS-USB setup packet encoding COMMUNICATION COMMANDS-USB setup packet encoding MODE COMMANDS-USB setup packet encoding command command type constant codes
OVERVIEW
DS2490 directly interfaces port 1-Wire bus. shown Figure DS2490 incorporates physical interface, device controller coupled with 1-Wire-specific function core, 1-Wire interface controller. 1-Wire interface controller shapes slopes 1-Wire waveforms, applies strong pullup reads 1-Wire using non-TTL threshold maximize noise margin best performance large 1-Wire Networks. 1-Wire waveform timing accurately controlled with crystal-based oscillator. DS2490 also supports remote wake-up which enables DS2490-based peripheral send resume signaling suspended host system. remote wake-up function enabled host system suspended state, 1-Wire device attachment will cause DS2490 perform host system wake-up allow 1-Wire device serviced.
DS2490 FUNCTIONAL BLOCK DIAGRAM Figure
SUSO
DESC 1-WIRE CONTROLLER
XCVR
DEVICE CONTROLLER
1-WIRE FUNCTION CORE
FIFOS
1-WIRE
CNTL
Typical application examples DS2490 shown Figure shown examples, host control communication with device accomplished over communication link. vendor-specific command set, defined this document, used select operational modes (MODE COMMANDS), control command processing (CONTROL COMMANDS), communicate over 1-Wire interface (COMMUNICATION COMMANDS). Shown Figure example DS2490-based peripheral application. peripheral function 1-Wire adapter provides both 1-Wire connections. this example, peripheral attached enabled host computer either directly root port through hub. 1-Wire interface provided DS2490 supports 1-Wire devices manufactured Dallas Semiconductor well
DS2490
various 1-Wire topologies simple multi-drop complex 1-Wire Network. Example Figure variations example which DS2490 embedded host computer HUB.
DS2490 APPLICATION EXAMPLES Figure
1-WIRE INTERFACE CONTROLLER
1-Wire communication commands sent DS2490 ultimately processed 1-Wire interface controller. tasks interface controller actively shape edges 1-Wire communication waveforms. This speeds recharging 1-Wire (rising edges) reduces ringing long lines (falling edges). circuitry shaping rising edges always active. slew rate falling edges actively controlled only flexible speed requires parameter slew rate control being different from power-on default value. MODE COMMANDS section parameter control power-on defaults.
Rising Edges
active pullup rising edges reduces rise time 1-Wire significantly compared simple resistive pullup. Figure shows DS2490 involved shaping rising edge.
DS2490
ACTIVE PULLUP Figure
IAPTO APUOT
IAPO 1-Wire discharged
circuit operates follows: pulldown (induced DS2490 device bus) ends. From this point 1-Wire pulled high weak pullup current IWEAKPU provided DS2490. slope determined load value pullup current. voltage crosses threshold voltage VIAPO. Now, DS2490 switches over from weak pullup current IWEAKPU higher current IACTPU. consequence, voltage rises faster. voltage crosses threshold VIAPTO timer started. long this timer (tAPUOT), IACTPU current will continue flow. After timer expired, DS2490 will switch back weak pullup current.
Falling Edges (DS2490-initiated)
Whenever DS2490 begins pulling 1-Wire initiate time slot, example, first turns weak pullup current IWEAKPU. Then, regular overdrive speed will generate falling edge slew rate typically V/µs. This value acceptable short 1-Wire busses adequate communication overdrive speed. 1-Wire networks more than roughly length, flexible speed should always used. parameters that adjustable flexible speed slew rate DS2490-initiated falling edges. effect slew rate control shown Figure
SLEW RATE CONTROL Figure
Target long lines: slew rate high slew rate 1-Wire pulled weak pull-up ends, pull-down begins
Extensive tests have shown that 1-Wire networks with lengths 300m will perform best fall time range 0.5µs. This translates into slew rate approximately 1V/µs. This slew rate typically achieved selecting PULLDOWN SLEW RATE parameter code (see MODE COMMANDS). actual measured fall time longer than target value, parameter code
DS2490
lower should used. fall time shorter, parameter code higher should used. Once determined, value code PULLDOWN SLEW RATE control parameter should stored host always loaded into DS2490 after power-on master reset cycle.
1-WIRE TIMING DIAGRAMS
This section explains 1-Wire waveforms generated DS2490. First, communication waveforms such reset/presence detect sequence read/write data time slots discussed followed detailed description Pulse function under various conditions.
1-Wire Communication Wave Forms
major features DS2490 that relieves host from generating timing 1Wire signals sampling 1-Wire appropriate times. reset/presence detect sequence shown Figure This sequence composed four timing segments: reset time tRSTL, short/interrupt sampling offset tSI, presence detect sampling offset tPDT delay time tFILL. timing segments tSI, tPDT tFILL comprise reset high time tRSTH where 1-Wire slave devices assert their presence interrupt pulse. During this time, DS2490 pulls 1-Wire high with weak pullup current. Reset/presence timing values shown Figure values timing segments 1-Wire speed options shown table. Since reset/presence sequence slow compared time slots, values regular flexible speed same. Except falling edge presence pulse, edges controlled DS2490. shape uncontrolled falling edge determined capacitance 1-Wire number, speed, sink capability slave devices connected.
RESET/PRESENCE DETECT Figure
SPEED REGULAR OVERDRIVE FLEXIBLE
NOMINAL TIMING VALUES tPDT tFILL tRSTL 512µs 64µs 512µs 64µs 64µs 512µs 64µs 512µs
tRSTH 584µs 74µs 584µs
Upon executing 1-WIRE RESET command (see COMMUNICATION COMMANDS), DS2490 pulls 1-Wire tRSTL then lets back DS2490 will wait short/interrupt sampling offset expire then test voltage 1-Wire determine there short interrupt signal. there short interrupt DS2490 will wait tPDT test voltage 1-Wire presence pulse. Regardless result presence test,
DS2490
DS2490 will then wait tFILL expire then, depending value embedded 1-WIRE RESET command bits PST, NTF, ICP, generate command response byte that available host. test interrupt short reveals logic DS2490 will wait 4096µs then test 1Wire again. logic detected, 1-Wire shorted DS2490 feedback response 1-WIRE RESET communication command will indicate short detection. logic detected, device will wait tFILL expire, after which will load feedback response value 1-WIRE RESET command with alarming presence pulse detect value. DEVICE FEEDBACK section additional details. additional testing presence pulse will done. DS2490 will perform short/interrupt testing described also overdrive speed, although interrupt signaling only defined regular speed. shown Figure Write-1 Read Data time slot comprised segments tLOW1, tDSO, tHIGH. During Write-1 time slots, after Write-1 time (tLOW1) expires, DS2490 waits duration data sample offset then samples 1-Wire voltage read response. After this, waiting time tHIGH1 must expire before time slot complete. shown Figure Write-0 time slot consists segments tLOW0 tREC0. Since defaults regular speed exceed 1-Wire sampling maximum most 1-Wire devices (tLOW1 tDSO 20µs) recommended always flexible speed. minimum flexible speed settings tLOW1 tDSO 10µs suffice most applications. network large heavily loaded, Write-1 time (tLOW1) should extended more than allow 1-Wire completely discharge. Since large heavily loaded network needs more time recharge, also recommended delay sampling reading. higher Data Sample Offset value (tDSO) will increase voltage margin also provide extra energy slave devices when generating long series Write-0 time slots. However, total tLOW1 tDSO should exceed 15µs. Otherwise, slave device responding have stopped pulling when transmitting logic Note that some long line loading conditions extend line recovery total tLOW1 tDSO extended. Care must taken violate tMSR attached 1-Wire devices.
DS2490
WRITE READ DATA TIME SLOT Figure
NOMINAL TIMING VALUES SPEED REGULAR OVERDRIVE FLEXIBLE* tLOW1 1.4µs 11µs tDSO 16µs 10µs 24µs tHIGH1 46µs 46µs tSLOT 66µs 10.4µs 60µs 81µs
*Powerup defaults Flexible speed: tLOW1 8µs, tDSO 18µs
WRITE TIME SLOT Figure
NOMINAL TIMING VALUES SPEED REGULAR OVERDRIVE FLEXIBLE* tLOW0 56µs 7.4µs 56µs tREC0 16µs 10µs 24µs tSLOT 72µs 10.4µs 66µs 80µs
*Powerup defaults Flexible speed: tREC0 18µs
DS2490
Pulse Wave Forms
PULSE COMMUNICATION COMMAND used generate strong pullup duration pulses specified with STRONG PULLUP DURATION mode register. Figure shows timing pulse. predefined pulse durations, tSPU known value, semi-infinite infinite durations these pulse times vary depend characteristics attached 1-Wire devices and/or host processor intervention. MODE COMMAND section details duration times. shown figure, processing PULSE command begins, pulse ends. Certain applications require duration strong pullup that cannot realized using predefined values (see MODE COMMANDS section values). Selecting infinite duration allows host generate pulses length. consequence, however, host becomes responsible actively control duration pulse. Failing require power-on reset master-reset cycle DS2490. this reason, infinite duration should only used absolutely necessary. HALT EXECUTION WHEN DONE HALT EXECUTION WHEN IDLE control commands used terminate infinite duration pulse.
STRONG PULLUP PRE-DEFINED DURATION Figure
COMMUNICATION
Communication with DS2490 performed using standard requests, also referred core commands requests this document, DS2490 vendor specific commands. command communication with DS2490 performed over default control pipe. Non-command communication, including 1-Wire device data DS2490 status information, occurs vendorspecific fashion over bulk interrupt pipes. Configuration DS2490 controller shown Figure shown, Dallas Semiconductor vendor-specific 1-Wire device exists with single 1-Wire interface. vendor-specific 1-Wire function DS2490 will implemented controlled device driver device level device class hierarchy, i.e, vendor-specific commands, will directed device level. Within 1-Wire interface, four endpoints exist control communicate with device. Four alternate settings 1-Wire interface exist that correspond different operating modes endpoints. Endpoint interface descriptions summarized following paragraphs. DS2490 provides remote wake-up capability. specification, device supports remote wake-up, must also provide ability enable disable remote wake-up function. addition, remote wake-up feature must disabled power default device reset state. When remote wake-up feature enabled, DS2490 will send resume signaling suspended host system upon detecting 1-Wire device attachment. then becomes responsibility host system software resume operation determine what servicing required 1-Wire device.
DS2490
CONFIGURATION Figure
HOST DS2490 1-WIRE DEVICE 1-WIRE INTERFACE ENUMERATION SYSTEM CONTROL default pipe 1-WIRE MODE 1-WIRE CONTROL 1-WIRE COMMUNICATION
interrupt pipe
TOUCH DETECTION DEVICE STATE
1-WIRE CLIENT bulk pipe bulk pipe PHYSICAL 1-WIRE DATA
Endpoint (EP) Summary Description
endpoint bi-directional default control pipe. used enumeration process, core request communication, DS2490 specific command communication. endpoint interrupt pipe (device host) used relay DS2490 status register data specific command execution completion and/or error information host. also used inform host 1-Wire device-attach detection. polling period requested either 10ms 1ms, depending alternate interface setting 1-Wire interface. default polling period 10ms. endpoint bulk data pipe (data from host) used transmit 1-Wire device data from host DS2490. information received this endpoint will transmitted data 1-Wire bus. endpoint bulk data pipe (data host) used send data received DS2490 from 1-Wire back host processing.
1-Wire Interface Summary Description
interface collection point four endpoints. Four alternate settings exist 1Wire interface which correspond different operational modes pipes EP1, EP2, EP3. shown Table alternate settings specify different polling periods interrupt pipe different maximum packet sizes bulk pipes.
DS2490
1-Wire Interface Alternate Setting Summary Table
Setting poll interval 10ms 10ms EP2/EP3 packet size bytes bytes bytes bytes Alternate Setting Description Long interrupt polling interval, small packet size bulk pipes Long interrupt polling interval, large packet size bulk pipes Short interrupt polling interval, small packet size bulk pipes Short interrupt polling interval, large packet size bulk pipes
Endpoint Feature Summary Table
Endpoint Transaction Type CONTROL INTERRUPT BULK Direction1 IN/OUT Max. Packet Size I/F-0.3: bytes I/F-0.3 bytes I/F-0: bytes I/F-1: bytes I/F-2: bytes I/F-3: bytes I/F-0: bytes I/F-1: bytes I/F-2: bytes I/F-3: bytes
BULK
Direction this table reference Host
Core Commands Table
Standard Device Requests SET_ADDRESS SET_CONFIGURATION GET_CONFIGURATION GET_DESCIPTOR GET_INTERFACE SET_INTERFACE SET_FEATURE CLEAR_FEATURE GET_STATUS Target Element Device Device Device Device Interface Interface Device Device Device, Interfaces, Endpoints Range 0x01 0x1F 0x00 0x01 0x00 0x01 Interface 0x00 0x03 Interface 0x00 0x03 Notes
DS2490
Notes:
only valid configuration values SET_CONFIGURATION request. Configuration value corresponds non-configured state. Only DEVICE CONFIGURATION descriptor types supported GET_DESCRIPTOR request. Interface only valid interface value DS2490. only valid feature selector command DEVICE_REMOTE_WAKE-UP. DS2490 intended, minimum, partially powered. Remote wake-up enabled disabled. GET_STATUS requests device will return logic self-powered field current state value remote wake-up bit. There core level status information defined interfaces Specification v1.1. DS2490 will always return value data GET_STATUS requests interfaces.
DS2490 Vendor-Specific Commands
Three different vendor-specific command types exist control communicate with DS2490: Control, Communication, Mode. Control commands used manage various device functions including processing communication commands, buffer clearing, reset. Communication commands used 1-Wire data command I/O. Mode commands used establish 1-Wire operational characteristics DS2490 such slew rate, time, strong pullup, etc. Control, Communication Mode commands, like core requests, communicated over default control pipe EP0. With exception noted below, each command associated parameter data individually formatted into 8-byte control transfer setup packet follows: bmRequestType bRequest wValue wIndex wLength Request type Command Type Command Command Parameters bytes) byte) byte) bytes) bytes) Note Note
Notes:
exception wValue formatting READ STRAIGHT Communication command. This command requires three parameter bytes that exceed 2-byte parameter encoding space available wIndex field. this command only, wValue field will formatted command byte parameter byte. command description Appendix details. wLength field used COMM CMDS Control command specify number command/parameter bytes retrieve from DS2490 command FIFO; command description specifics. other cases wLength field used must 0x0000. bit-mapped bmRequestType field identifies characteristics command Chapter Specification. Fields included this command describe direction transfer, type request (core, class, vendor specific) target command recipient (device, interface, endpoint). only variation bmRequestType field different DS2490 vendor-specific command will transfer direction: host device, device host; recipient commands will device. bRequest field contains 1-byte constant identifying which three supported DS2490 command types being sent. command constants defined Appendix summarized follows:
DS2490
Command Type CONTROL_CMD COMM_CMD MODE_CMD
Description 1-Wire interface control commands 1-Wire interface communication commands 1-Wire interface operational mode commands
2-byte wValue field encoded with specific command. Control Mode commands, field value corresponds specific command constant defined Appendix Communication commands, field additional embedded command parameters indicated Appendix exception READ STRAIGHT command described previously. 2-byte wIndex used hold additional command parameter data when required specific command. wLength field used control transfer setup packet specify number bytes sent during data stage control transfer. "GET COMM CMDS" control command only DS2490 command that uses data stage control transfer. Typically, command data embedded setup stage. Except COMM CMDS, this field must 0x0000. DS2490 Control, Communication, Mode vendor-specific command descriptions formatting defined Appendices Vendor-specific commands defined appendices supported DS2490 device will respond with STALL unsupported command received.
MODE COMMANDS
DS2490 1-Wire characteristics features (speed, durations, slew rate, etc.) controlled with discrete Mode commands and/or embedded Communication command parameters. Parameter values enable/disable settings used characteristic control. Mode settings stored DS2490 State Registers read time polling interval EP1. section "DEVICE FEEDBACK" State Register details. Enable/disable settings used control global features: Strong pullup Dynamic 1-Wire communication speed change through communication command settings these three global controls accessible only through Mode commands; features either enabled disabled with appropriate Mode command. Specific Communication commands exist issue strong pullup, speed change. When corresponding setting enabled feature usable part communication command when disabled feature usable. Parameter values codes used specify control 1-Wire characteristics: 1-Wire communication speed strong pullup duration Pulldown slew rate Write-1 time Data sample offset/Write-0 Recovery time These five settings controllable with discrete Mode commands embedded command/parameter values Communications commands.
DS2490
listed Table summarized previously, there eight Mode commands. control transfer setup packet coding transmit these commands detailed Appendix Mode commands immediately processed DS2490 when they received. DS2490 power-on default values these parameters listed Table Each command parameter control detailed following paragraphs.
Mode Command Summary Table
Command ENABLE PULSE ENABLE SPEED CHANGE 1-WIRE SPEED STRONG PULLUP DURATION PULLDOWN SLEW RATE WRITE-1 TIME DSOW0 RECOVERY TIME Function Enable/disable 1-Wire strong pullup pulse Enable/disable dynamic change 1-Wire speed through communication command. Communication speed 1-Wire bus. Duration 1-Wire strong pullup. Slew rate 1-Wire pulldown. Duration 1-Wire Write-1 time. Recovery time 1-Wire data sample offset Write-0 transaction.
Mode Command Descriptions:
ENABLE PULSE-This command used enable disable 1-Wire strong pullup pulse position parameter byte used control enabled/disabled state pulse. pulse enabled when respective disabled when DS2490 power-up default state strong pullup disabled. ENABLE SPEED CHANGE-This command used enable disable 1-Wire communication speed change. Enabled when TRUE parameter value passed with command, disabled with FALSE. DS2490 power-up default state speed change disabled. 1-WIRE SPEED-This command used speed 1-Wire communication; three settings possible. parameter codes select desired required speed listed Table shown, speed codes 0x3.0xF undefined. DS2490 decodes LSBs 1-Wire speed code. Sending code other than defined values Table will result undefined behavior. DS2490 power-up default communication speed regular.
1-Wire Speed Codes Table
Code 0x3.0xF Speed Regular Flexible Overdrive reserved Data Rate time slot (15.4kbps) time slot (13.9kbps 15.4kbps) time slot (100kbps) undefined
DS2490
STRONG PULLUP DURATION-This command used time duration 1-Wire strong pullup. shown Table time controlled with unsigned 8-bit binary number between 0x00 0xFE which specifies duration multiples 16ms. value 0x01 specifies 16ms, 0x02 equals 32ms, etc. value 0x00 specifies infinite duration. Parameter value 0xFF reserved will cause device deliver pullup duration <1s. terminate infinite duration pullup either HALT EXECUTION WHEN DONE HALT EXECUTION WHEN IDLE Control commands described Appendix DS2490 power-up default strong pullup duration register value 512ms.
Strong Pullup Duration Codes Table
Value 0x00 0x01 0x02 0xFE 0xFF Nominal Strong Pullup Duration infinite 16ms 32ms 4.064s reserved
PULLDOWN SLEW RATE-This command used select pulldown slew rate 1-Wire Flexible Speed operation; eight pulldown slew rates possible. parameter codes select desired required slew rate listed Table slew rate numbers table represent nominal values. nominal pulldown slew rate Regular speed 0.83V/s Overdrive speeds 15V/s. DS2490 decodes three LSBs slew rate code. Sending code other than defined values Table will result undefined behavior. DS2490 pulldown slew rate power-up default value Flexible speed 0.83V/s.
Flexible Speed Pulldown Slew Rate Codes Table
Code 0x8.0xF Nominal Pulldown slew rate 15V/s 2.20V/s 1.65V/s 1.37V/s 1.10V/s 0.83V/s 0.70V/s 0.55V/s reserved
WRITE-1 TIME-This command used select Write-1 time 1-Wire Flexible speed operation; eight Write-1 time durations possible. parameter codes select desired required time listed Table time numbers table represent nominal values. nominal Write-1 Time Regular speed Overdrive speed 1.4s. DS2490 decodes three LSBs time code. Sending code other than defined values Table will result undefined behavior. DS2490 Write-1 Time power-up default value Flexible speed
DS2490
Flexible Speed Write-1 Time Codes Table
Code 0x8.0xF Nominal Write-1 Time reserved
DSOW0 RECOVERY TIME-This command used select Data Sample Offset (tDSO) Write-0 recovery (tW0R) time (DSO/W0R) 1-Wire Flexible Speed operation; eight DSO/W0R times possible. parameter codes select desired required recovery time listed Table numbers table represent nominal values. nominal DSO/W0R time Regular speed 16s, Overdrive speed Data Sample Offset Write-0 Recovery Time DS2490 decodes three LSBs DSO/W0R code. Sending code other than defined values Table will result undefined behavior. DS2490 DSO/W0R power-up default value Flexible speed 18s.
Flexible Speed DSO/ Time Codes Table
Code 0x8.0xF Nominal DSO/W0R Time reserved
Power-on Default Mode Values
Table summarizes power-up default values various DS2490 mode registers. Note that power-up default communication speed regular several values listed Table specific Flexible speed operation. change value appropriate Mode Communication command must sent device.
DS2490
1-Wire Power-On Default Modes Table
Setting/Parameter Strong pullup Dynamic Speed Change 1-Wire Communication Speed Strong Pullup Duration Pulldown Slew Rate Control Write-1 Time Data Sample Offset Write-0 Recovery Time Power-On Default Value FALSE FALSE (Regular Speed, ~16kbps) 0x20 (512ms) (0.83V/s) (8s) (18s)
CONTROL COMMANDS
DS2490 Control commands used control processing Communication commands/data also used issue device Reset. listed Table there Control commands. control transfer setup packet coding transmit these commands detailed Appendix Like Mode commands, Control commands immediately processed DS2490 when they received.
Control Command Summary Table
Command RESET DEVICE START EXECUTION RESUME EXECUTION HALT EXECUTION WHEN IDLE HALT EXECUTION WHEN DONE FLUSH COMM CMDS FLUSH DATA BUFFER FLUSH DATA BUFFER COMM CMDS Function Perform hardware reset. Start execution Communication commands. Resume execution Communication commands. Halt Communication command execution when 1-Wire idle. Halt further Communication command execution when current command execution completes. Clear unexecuted Communication commands from command buffer. Clear data receive buffer (data from 1-Wire device). Clear data transmit buffer (data 1-Wire device). Retrieve unexecuted Communication commands from command buffer.
DS2490
Control Command Descriptions:
RESET DEVICE-This command performs hardware reset equivalent power-on reset. This includes clearing endpoint buffers loading Mode control registers with their default values. START EXECUTION-This command starts execution Communication commands. This command also required start execution Communication commands with (immediate execution control) logic RESUME EXECUTION-This command used resume execution Communication command that halted with either HALT EXECUTION commands. HALT EXECUTION WHEN IDLE-This command used halt execution current Communication command after 1-Wire returned idle state. Further Communication command processing stopped until RESUME EXECUTION command received. This command, HALT EXECUTION WHEN DONE command, also used terminate strong pullup semiinfinite infinite duration. HALT EXECUTION WHEN DONE-This command used halt execution Communication command after current command execution complete. Further Communication command processing stopped until RESUME EXECUTION command received. This command, HALT EXECUTION WHEN IDLE command, also used terminate strong pullup semiinfinite infinite duration. FLUSH COMM CMDS-This command used clear unexecuted Communication commands from command FIFO. DS2490 must halted state before FLUSH COMM CMDS command processed. FLUSH DATA BUFFER-This command used clear receive data FIFO (data from 1Wire device). DS2490 must halted state before FLUSH DATA BUFFER command processed. FLUSH DATA BUFFER-This command used clear transmit data FIFO (data 1Wire device). DS2490 must halted state before FLUSH DATA BUFFER command processed. COMM CMDS-This command used retrieve unexecuted Communication commands parameters from command FIFO. DS2490 must halted state before COMM CMDS command processed. Unexecuted commands returned over control transfer data phase. Host software responsible determining number command/parameter bytes returned specifying value wLength field control transfer setup packet. Commands/parameters deleted from FIFO they transmitted host; command pointer used with FIFO updated values read. commands/parameters that transferred remain FIFO will processed when command execution resumes. wLength value passed larger than number command/parameter bytes, DS2490 will terminate control transfer with short data packet.
DS2490
COMMUNICATION COMMANDS
Communication commands used communicate with control attached 1-Wire device(s). There Communication commands summarized Table Communication commands also contain embedded command bits conditional control additional functionality. Appendix details embedded command purpose/formatting well control transfer setup packet coding transmit command/parameter data DS2490. Unlike Mode Control commands, Communication command processing controlled host software setting embedded command bits within Communication command. example, command macro form supported which several Communication commands parameter data sent/buffered DS2490 then processed group. Embedded command used create macro command sets. Also, unlike Mode Control commands, several forms Communication command monitoring exist host software track processing progress. Depending settings embedded communication command bits NTF, APPENDIX Result Register value generated provide command processing feedback. Communication command buffer (FIFO) status 1-Wire data transmit/received buffers (EP2/3 FIFOs) status also monitored State Registers. section "DEVICE FEEDBACK" details command monitoring.
Communication Command Summary Table
COMMAND DURATION PULSE 1-WIRE RESET BYTE BLOCK MATCH ACCESS READ STRAIGHT RELEASE PATH WRITE SRAM PAGE READ PROT PAGE READ REDIRECT PAGE W/CRC SEARCH ACCESS FUNCTION Change duration strong pullup. Perform strong pullup. Generate 1-Wire reset pulse. 1-Wire single data I/O. 1-Wire data byte I/O. 1-Wire data block I/O. Address device 1-Wire bus. Transmit data preamble read back data. Control Crytpo iButton activity. Activate series couplers that provide access target 1-Wire device. Write data scratchpad 1-Wire SRAM device. Read protected pages 1-Wire EPROM device tamperdetect bytes counter value Monetary iButtons. Read single page data check CRC. Follow page redirections set. Access device using Search command identifying devices active segments 1-Wire Network.
DS2490
Communication Command Descriptions:
DURATION-This command changes State Register pulse duration value strong pullup. duration value loaded into duration register detailed Appendix duration value alternatively changed using Mode command. duration setting remains effective until changed another DURATION MODE Command. section "MODE COMMANDS" duration parameter value setting.
Note:
infinite duration pulse terminated using either HALT EXECUTION Control commands. resume 1-Wire activity after termination, RESUME EXECUTION Control command. Command parameters: data: data: Result Register: byte specifying duration. None, this command gets input data command parameter. None result data generated. result value 0x00 will generated. result data generated since there error codes associated with this command.
PULSE-This command used generate strong pullup order provide extra power attached iButton device, e.g., temperature sensor, EEPROM, SHA-1, crypto iButton. pulse duration determined value mode register. None Command parameters: None data: None data: Result Register: Code Condition 0x00 error detected None error detected None
DS2490
1-Wire RESET-This command used generate reset pulse 1-Wire optionally change 1-Wire speed. speed will take effect only embedded command When 1-WIRE RESET sent after Overdrive Skip command, must speed must 0x02. MODE CONTROL section additional communication speed information. switch back regular speed, speed parameter 0x00 (regular) 0x01 (flexible). byte specifying speed after reset. Command parameters: None data: None data: Result Register: Code Condition NRS, abnormal condition Alarming Presence Pulse detected 0x00 error detected None error detected None This command generates single time slot 1-Wire reads back response. Data command byte specifies value written 1-Wire bus. This time slot optionally followed strong pullup using embedded command bits CIB. With requested strong pullup will only occur read-back revealed Data returned host only embedded command read from 1-Wire device stored FIFO read host using bulk transaction. None. Command parameters: None, this command gets input data command parameter. data: data: Length Description byte read back from 1-Wire device. None data returned. result data generated. Result Register: result value 0x00 will generated. result data generated since there error codes associated with this command.
Read Back Byte Table
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
BYTE I/O-This command accomplishes direct 1-Wire write read with optional strong pullup after last byte. optional strong pullup controlled using embedded command SPU. write sequence, data byte written included command setup packet shown Appendix read sequence, setup packet data byte value 0xFF. Data returned host only embedded command byte read from 1-Wire device stored FIFO read host using bulk transaction.
DS2490
Command parameters:
byte: Data byte sent 1-Wire bus. read only, byte should 0xFF. None, this command gets input data command parameter. data: data: Length Description byte Byte read back from 1-Wire device. None data returned. result data generated. Result Register: result value 0x00 will generated. result data generated since there error codes associated with this command.
BLOCK I/O-This command accomplishes direct 1-Wire write read with optional strong pullup after last byte block. optional strong pullup controlled using embedded command SPU. Embedded command enables 1-Wire reset before command executes. accomplish READ function input data should 0xFF, otherwise data read from 1-Wire will masked. block write sequence FIFO must pre-filled with data before command execution. Additionally, block sizes greater then FIFO size, FIFO content status must monitored host that additional data sent FIFO when necessary. similar FIFO content monitoring requirement exists block read sequences. During block read number bytes loaded into FIFO must monitored that data read before FIFO overflows. bytes specifying block size. Command parameters: data: Length Description Same block Data block written 1-Wire device. size data: Length Description Same block Data block read from 1-Wire device. size result data generated. Result Register: result value 0x00 will generated. result data generated since there error codes associated with this command. MATCH ACCESS-This command used address device active section 1-Wire using Match Overdrive Match command code. FIFO must pre-filled with bytes target before command execution. Embedded command enables 1-Wire reset before command executes, embedded command enables 1-Wire speed change that takes effect before command executes.
DS2490
Command parameters: data: data: Result Register:
bytes: match command byte, 1-Wire speed byte (optional). Length Description bytes device accessed. None result data generated. result value 0x00 will generated. result data generated since there error codes associated with this command.
READ STRAIGHT-This command transmits user-specified preamble data 1-Wire then reads back many bytes specified. preamble typically consists 1-Wire command code followed TA2. possible include Match command preamble also address device current speed. This command also used copy scratchpad disconnect path. Embedded command enables 1-Wire reset before command executes. FIFO must pre-filled with preamble data before command execution. Additionally, preamble sizes greater then FIFO size, FIFO content status must monitored host that additional data sent FIFO when necessary. similar FIFO content monitoring requirement exists block read. During block read, number bytes loaded into FIFO must monitored that data read before FIFO overflows. bytes: 2-byte parameter specifying block read size, byte specifying Command parameters: preamble size. data: Length Description Same Preamble data written 1-Wire device. preamble size data: Length Description Same block Data block read from 1-Wire device. size result data generated. Result Register: result value 0x00 will generated. result data generated since there error codes associated with this command. RELEASE-This command typically used control activity crypto iButton, which requires release sequence. This command also used read from write buffer Status Register crypto iButton. short preamble bytes) consists 1-Wire command code followed release sequence. four-byte preamble with embedded command consists 1-Wire command code followed length byte release sequence. 4-byte preamble with embedded command consists 1-Wire command code followed status byte release sequence. long preamble (minimum bytes, embedded command consists 1-Wire command, length byte, data bytes release sequence. this case, length byte indicates total number bytes between length byte release sequence. least significant byte release sequence transmitted first. Embedded command must when trying (start, continue) crypto iButton. other cases, should Additionally, embedded command used clear communication command buffer EP2/3 FIFOs error occurs during execution command. FIFO must pre-filled with preamble data before command execution. Additionally, preamble sizes greater then FIFO size,
DS2490
FIFO content status must monitored host that additional data sent FIFO when necessary. similar FIFO content monitoring requirement exists block read. During block read number bytes loaded into FIFO must monitored that data read before FIFO overflows. byte specifying preamble size. Command parameters: data: Length Description Same Preamble data written 1-Wire device. preamble size data: Length Description preamble specified Data read from 1-Wire device. size second byte preamble None data returned (this write application). Result Register: Code Condition CRC, release sequence accepted. 0x00 error detected None error detected None PATH-This command used activate series couplers that finally provide access target 1-Wire device. Embedded command enables 1-Wire reset before command executes. Additionally, embedded command used clear communication command buffer EP2/3 FIFOs error occurs during execution command. FIFO must pre-filled with coupler data before command execution. Additionally, coupler data sizes greater then FIFO size, FIFO content status must monitored host that additional data sent FIFO when necessary. Upon completion command execution, FIFO loaded with 1-byte value that indicates number couplers activated. error code indication that there presence pulse branch that connected.
DS2490
Command parameters: data:
data:
Result Register:
byte specifying number couplers that need activated set-up path target device. Length Description bytes bytes coupler activated level followed Smart-On command code either main auxiliary 1-Wire coupler output. Length Description byte Number couplers successfully activated; should same number levels. Code Condition CMP, error condition detected. 0x00 error detected None error detected None
WRITE SRAM PAGE-This command used write data scratchpad SRAM device optionally check CRC. copy data final memory location, required send READ STRAIGHT command with "copy scratchpad" preamble block size. Embedded command activates CRC16 generator. This command also applicable Write function Crypto iButton embedded command write partial page page size parameter target address need accordingly. FIFO must pre-filled with preamble SRAM data before command execution. Additionally, data page sizes greater then FIFO size, FIFO content status must monitored host that additional data sent FIFO when necessary. byte specifying page size. This specifies number bytes Command parameters: sent 1-Wire device following 3-byte preamble. This number typically identical page size; value 0x00 indicates 256-byte page. data: Length Description 3-bytes page Preamble data bytes sent 1-Wire size SRAM device. 3-byte preamble: 1-Wire command code, TA1, (typical). 2-bytes page Preamble data bytes sent 1-Wire size SRAM device. 2-byte preamble: 1-Wire command code, length information. None data: Result Register: Code Condition error condition (only 0x00 error detected None error detected None
DS2490
READ PROT PAGE-This command used read multiple CRC-protected pages EPROM devices read tamper-detect bytes counter value Monetary iButtons. embedded command CRC16 generator selected; CRC8 used. Embedded command used specify either 3-byte read preamble. Additionally, embedded command used clear Communication command buffer EP2/3 FIFOs error occurs during execution command. command also used read single partial page that page reading PIOs DS2406. This command also applicable Read function crypto iButton FIFO must pre-filled with preamble data before command execution. prevent overflow, FIFO must monitored (and read necessary) during command execution reading more data than size FIFO. bytes: byte page size, byte number pages. Note that Page Size byte parameter value must form log2(actual page size). example, actual page size 3210, then Page Size parameter would need 0x05. Typical page sizes decimal data memory status memory. page size 0x00 indicates 256-byte page. data: Length 3-bytes 3-byte preamble: 1-Wire command code, TA1, (typical). 2-bytes 2-byte preamble: 1-Wire command code, length information. data: Length Description (page size Data read from 1-Wire device. number pages) Result Register: Code Condition error condition. 0x00 error detected None error detected None Command parameters: READ REDIRECT PAGE W/CRC-This command used read single page data check CRC. page redirected, host will receive page number data. page redirected embedded command device will follow trail redirections until page found that redirected. When found, host will receive page number data that particular page. first read attempt reveals redirection host will only receive number page addressed page redirected Reading starts page boundary. Additionally, embedded command used clear communication command buffer EP2/3 FIFOs error occurs during execution command. error code indication infinite loop. FIFO must pre-filled with command code data before command execution. prevent overflow, FIFO must monitored (and read necessary) during command execution reading more data than size FIFO.
DS2490
Command parameters:
data:
data: page redirected: page redirected: Result Register:
bytes: byte page size, byte page address. Page size byte indicates number bytes that considered page. Typical page sizes decimal data memory, status memory, decimal Monetary iButtons. page size 0x00 indicates 256-byte page. page address specifies page number used first read attempt. Length bytes bytes 1-Wire device accessed followed 1-Wire command code "Extended Read Memory". Length Description byte page Page number contents page. size byte Number page addressed page redirected Code Condition RDP, CRC, error condition. 0x00 error detected None error detected None
SEARCH ACCESS-The SEARCH ACCESS command used either access device using Search command identify devices active segments 1-Wire Network. Embedded command used specify type search. Embedded command used control discrepancy information reporting. Additionally, embedded command used clear Communication command buffer EP2/3 FIFOs error occurs during execution command. error code indicates that there response least bits search. FIFO must pre-filled with data before command execution. prevent overflow, FIFO must monitored (and read necessary) during command execution returning more data than size FIFO.
DS2490
bytes: byte 1-Wire command (Search Conditional Search ROM), byte number devices. number devices byte specifies maximum number devices discovered single command call. value 0x00 indicates that devices 1-Wire Network discovered. data: Length bytes 1-Wire device accessed with which start search data: Length Description None data returned. Varies, blocks devices discovered followed bytes. bytes discrepancy information numbers devices 1-Wire Network higher than specified second parameter. Result Register: Code Condition EOS, error condition. 0x00 error detected None error detected None Command parameters:
DS2490
DEVICE FEEDBACK
DS2490 state result feedback provided host over interrupt pipe. host interrupt polling period transfers controlled alternate setting 1-Wire Interface described section: 1-Wire Interface Summary Description. shown Table bytes feedback data returned. minimum, bytes STATE REGISTER data will delivered each polling interval transaction EP1); position definition these data values listed Table addition, shown Table between extra bytes RESULT REGISTER data will delivered with feedback data. This consists communication command processing result data controlled embedded communication command bits notification bytes 1-Wire device arrival detection. there less than bytes result state register data return, DS2490 will terminate transaction with short zero data packet. Data loaded into RESULT REGISTER buffer based embedded communication command bits upon detection 1-Wire device attachment. There defined offset position data values this buffer. Knowledge communication command ordering sent DS2490 must maintained host properly interpret returned data values. addition, parse data required determine whether 1-Wire detect value included; value 1-Wire detect byte unique. Table defines 1-Wire detect byte data values that result from Communication command processing.
Interrupt Transfer Data Summary Table
OFFSET 0x00 0x0F 0x10 0x1F1 DATA STATE REGISTERS RESULT REGISTERS
Notes:
number RESULT RESIGTER values will vary depending setting embedded communication command bits ICP, number communication commands processed since previous polling period, whether 1-Wire device detected.
DS2490 STATE REGISTERS Table
Description Enable Flags Offset 0x00 Data bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 -SPCE SPUE SPUE strong pullup enabled, disabled. SPCE dynamic 1-Wire speed change through Communication command enabled, disabled. These bits reserved. current 1-Wire speed code current pullup duration current pulldown slew rate code
1-Wire Speed Strong Pullup Duration (Reserved) Pulldown Slew Rate Control
0x01 0x02 0x03 0x04
DS2490
Description Write-1 Time Data Sample Offset Write-0 Recovery Time Reserved (Test Register) Device Status Flags
Offset 0x05 0x06 0x07 0x08
Data current Write-1 time code current data sample offset/ Write-0 recovery time code
bit7
EP0F
bit6
bit5
IDLE
bit4
HALT
bit3
PMOD
bit2
bit1
bit0
SPUA
Communication Command, Byte Communication Command, Byte Communication Command Buffer Status 1-Wire Data Buffer Status 1-Wire Data Buffer Status Reserved (Test Register) Reserved (Test Register)
0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F
Definitions: SPUA strong pullup currently active, inactive. Reserved Reserved PMOD DS2490 powered from external sources, DS2490 power provided from USB. HALT DS2490 currently halted, device halted. IDLE DS2490 currently idle, device idle. Reserved EPOF: Endpoint FIFO status, Note Communication command currently being processed. device idle, register value 0x00 sent. Communication command currently being processed. device idle, register value 0x00 sent. Number data bytes currently contained 16-byte FIFO used hold communication commands. Number data bytes currently contained 128-byte FIFO used write data 1-Wire bus. Number data bytes currently contained 128-byte command FIFO used read data from 1-Wire bus. Reserved Reserved
Notes:
EP0F Endpoint FIFO full when control transfer setup packet received. This error condition that setup packet received discarded full condition. recover from this state host must send CTL_RESET_DEVICE command; device will also recover with power reset cycle. Note that DS2490 will accept process CTL_RESET_DEVICE command EP0F state occurs. EP0F FIFO error condition exists.
DS2490
DS2490 RESULT REGISTERS Table
Offset1,2 0x10 0x11 0x1F Data value value value
Notes:
Since Result Registers follow State Registers interrupt transfers, register offset starting value shown Table Result Registers follows last value Table State Registers. number RESULT RESIGTER values will vary depending setting embedded communication command bits ICP, number communication commands processed since previous polling period, whether 1-Wire device detected.
DS2490 RESULT REGISTER VALUE DEFINITION Table
Data Value Description 1-Wire Device Detect Byte Communication Command Error Result Data 0xA5 bit3
bit7
bit6
bit5
bit4
bit2
bit1
bit0
Definitions: value indicates that SEARCH ACCESS with ended sooner than expected reporting less ID's than specified "number devices" parameter. value indicates that READ REDIRECT PAGE WITH/CRC encountered page that redirected. value indicates that error occurred when executing following commands: WRITE SRAM PAGE, READ PROT PAGE, READ REDIRECT PAGE W/CRC. value indicates error with following: Error when reading confirmation byte with PATH command. There difference between byte written then read back with BYTE command value indicates that 1-WIRE RESET revealed Alarming Presence Pulse. value indicates that 1-WIRE RESET revealed short 1-Wire PATH command could successfully connect branch short.
DS2490
Data Value Description
Data value indicates error with following: 1-WIRE RESET reveal Presence Pulse. PATH command Presence Pulse from branch that connected. response from more bits during SEARCH ACCESS command. value these fields indicates that error condition detected.
TRANSCEIVER
Integrated within DS2490 USB-compliant transceiver. comply with cable termination requirements, resistors external DS2490 must installed shown Figure tolerance resistors necessary bring total steady state resistance each driver range required core specification. 1.5k pullup resistor required identify DS2490 high speed device up-stream HUB. 33pF capacitors optional useful edge rate control bypassing high frequency energy ground reduction purposes.
Transceiver Termination Figure
3.3V 10%)
1.5k TO/FROM HIGH SPEED CABLE
DS2490 TRANSCEIVER
33pF
D33pF
DS2490
SUSPEND OUTPUT
Suspend output signal SUSO operation function both device state DS2490 (configured unconfigured) suspend state. truth table signal operation listed Table This signal could used stand-alone combined with other external signals power down circuitry external DS2490, such power sources. SUSO signal open drain output requires external pullup.
Suspend Output Operation Table
Device State unconfigured configured configured Suspend State don't care suspended suspended
SUSO
HIGH HIGH
OSCILLATOR
DS2490 requires single 12.0MHz crystal crystal oscillator clock source operate. Crystals CMOS crystal oscillators used provide clock sources. crystals, parallel resonant, fundamental mode with specification between 10pF 20pF required frequency. Parallel loading capacitors with value approximately twice also required. connection scheme shown Figure should used. external CMOS crystal oscillators, make connection directly DS2490 input. output must left floating this arrangement.
Oscillator Connection Figure
DS2490
DS2490
ABSOLUTE MAXIMUM RATINGS*
Voltage Relative Ground Operating Temperature Range Storage Temperature Range Soldering Temperature -0.5V +6.0V +125 J-STD-020A Specification
This stress rating only functional operation device these other conditions above those indicated operation sections this specification implied. Exposure absolute maximum rating conditions extended periods time affect reliability.
RECOMMENDED OPERATING CONDITIONS
PARAMETER Supply Voltage Digital Supply Voltage Second Supply Voltage Operating Temperature SYMBOL UNITS NOTES
NOTES:
Voltage referenced ground. Must tied During device power-up, supply application sequence order must VD/VD2,
ELECTRICAL CHARACTERISTICS
PARAMETER Operating Current Operating Current Suspend Current Suspend Current Operating Current D+/- Input High D+/- Input 1-Wire Input High 1-Wire Input
SUSO Output Active Pullup Timer Threshold Active Pullup Threshold 1-Wire Weak Pullup Current 1-Wire Active Pullup current Strong Pullup Voltage Drop 50mA load 1-Wire
4.4V 5.5V, 3.0V 3.6V
UNITS 1200 1.35 30.4 1540 NOTES
SYMBOL VIHU VILU VIH1 VIL1 VOL(SUSO) VIAPTO VIAPO IWEAKPU IACTPU VSTRPU
2.35 -0.3 3.55 -0.3 1.75 0.25
DS2490
NOTES:
Voltage difference between 1-WIRE. Applies both unconfigured configured states. Applies suspend state. Voltage referenced ground
CHARACTERISTICS CONDITIONS:
PARAMETER 1-Wire
4.4V 5.5V, 3.0V 3.6V
SPECIFICATION defined Chapter Specification section "1-WIRE INTERFACE CONTROLLER" this document
CAPACITANCE CONDITIONS:
PARAMETER Input Capacitance Output Capacitance Input/Output Capacitance SYMBOL COUT
UNITS NOTES
HW/SW APPLICATION RECOMMENDATIONS
schematic example 1-Wire Adapter peripheral shown Figure
DS2490
DESIGN EXAMPLE: 1-WIRE ADAPTER Figure
VBUS SHIELD
Filter
SHDN MAX8881 1.5K 33pF 33pF PMOD SUSO 1-WIRE DS2490S
33pF 12.0 33pF
Filter
BAT54S
RJ-11 DS9503P
Notes: Resistors 1/8W, unless noted. Capacitor values microfarads unless noted. Capacitor voltage ratings minimum. filters Murata BLM21P221SG equivalent.
DS2490
APPENDIX DS2490 CONTROL COMMANDS, SETUP PACKET ENCODING CONTROL COMMANDS RESET DEVICE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength START EXECUTION Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength RESUME EXECUTION Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength HALT EXECUTION WHEN IDLE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength
0x40 CONTROL_CMD CTL_RESET_DEVICE 0x0000 0x0000
0x40 CONTROL_CMD CTL_START_EXE 0x0000 0x0000
0x40 CONTROL_CMD CTL_RESUME_EXE 0x0000 0x0000
0x40 CONTROL_CMD CTL_HALT_EXE_IDLE 0x0000 0x0000
DS2490
CONTROL COMMANDS HALT EXECUTION WHEN DONE Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH COMM CMDS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH DATA BUFFER Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength FLUSH DATA BUFFER Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength
0x40 CONTROL_CMD CTL_HALT_EXE_DONE 0x0000 0x0000 DS2490 must halted state before FLUSH COMM CMDS command processed. 0x40 CONTROL_CMD CTL_FLUSH_COMM_CMDS 0x0000 0x0000 DS2490 must halted state before FLUSH DATA BUFFER command processed. 0x40 CONTROL_CMD CTL_FLUSH_RCV_BUFFER 0x0000 0x0000 DS2490 must halted state before FLUSH DATA BUFFER command processed. 0x40 CONTROL_CMD CTL_FLUSH_XMT_BUFFER 0x0000 0x0000
DS2490
CONTROL COMMANDS COMM CMDS Setup Packet Encoding: bmRequestType bRequest wValue wIndex wLength DS2490 must halted state before COMM CMDS command processed. 0xC0 CONTROL_CMD CTL_GET_COMM_CMDS 0x0000 variable value wLength field depends number communication commands parameters loaded FIFO.
APPENDIX DS2490 COMMUNICATION COMMANDS, EMBEDDED COMMAND BITS, SETUP PACKET ENCODING. Communication commands contain embedded command parameter bits wValue field. definitions parameters described below. NAME DESCRIPTION follows chain page redirected. stops reading page redirected. prevents strong pullup read back from 1Wire generally enables strong pullup reduces preamble size bytes (rather than sets preamble size bytes. Data value written 1-Wire bus. activates/selects CRC16 generator specifies CRC. clears buffers case error occurred during execution previous command; requires that previous command. prevents buffers from being cleared. indicates that command last macro; consequence command processing result feedback messages suppressed. indicates that command last macro single command operation; enables command processing result feedback signaling. enables immediate execution command. Assumes that 1-Wire device data required command been received EP2. prevents immediate execution command; execution must started through control function command. always generate communication command processing result feedback generate communication command processing result feedback only error occurs command result feedback suppressed either case, above.
DS2490
NAME
DESCRIPTION continuously generate 1-Wire Reset sequences until presence pulse discovered. generate only 1-Wire Reset sequence. performs read function. performs write function. inserts 1-Wire Reset before executing command. 1-Wire Reset inserted. returns discrepancy information host there more devices than could discovered current pass. does return discrepancy information. enable speed change 1-Wire bus. disable speed change 1-Wire bus. searches reports without really accessing particular device. makes "Strong Access" particular device. inserts strong pullup after Byte Block Release command. strong pullup. checks 0-bits byte written 0-bits byte read back form device. checks byte written identical read back from device.
COMMUNICATION COMMANDS DURATION Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte wIndex byte byte 0x00 (unused) byte duration: Unsigned 8-bit binary number MODE CONTROL section format information. wLength 0x0000
byte byte
specifying duration. byte weighting additional
DS2490
COMMUNICATION COMMANDS PULSE Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte wIndex 0x0000 wLength 0x0000 1-WIRE RESET Setup Packet Encoding: bmRequestType bRequest wValue
byte
wIndex
wLength Setup Packet Encoding: bmRequestType bRequest wValue
0x40 COMM_CMD byte byte byte byte byte 0x00 (unused) byte speed: 0x02 with after Overdrive Skip 0x01 0x00 with other cases don't care with 0x0000
byte byte
wIndex
wLength
0x40 COMM_CMD byte byte byte byte byte 0x00 (unused) byte 0x00 (unused) 0x0000
byte byte
DS2490
COMMUNICATION COMMANDS BYTE Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte byte wIndex byte byte byte 0x00 (unused) byte data byte sent 1-Wire bus. read only, byte should 0xFF. wLength 0x0000 BLOCK Setup Packet Encoding: bmRequestType bRequest wValue
wIndex
wLength
0x40 COMM_CMD byte byte byte byte byte byte byte block size (HI), most significant byte byte block size (LOW), least significant byte 0x0000
DS2490
COMMUNICATION COMMANDS MATCH ACCESS Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte byte wIndex byte byte byte speed: 0x02 with after Overdrive Skip 0x01 0x00 with other cases don't care with byte 1-Wire command: Command used addressing 1-Wire device. Valid codes: 0x55 (Match ROM) 0x69 (Overdrive Match ROM) wLength 0x0000 READ STRAIGHT Setup Packet Encoding: bmRequestType bRequest wValue
wIndex
wLength
0x40 COMM_CMD byte byte byte Preamble size. Number bytes written. byte byte byte byte Block size Number bytes read, most significant byte. byte Block size LOW. Number bytes read, least significant byte. byte byte byte 0x00 (not used) byte Preamble size. Number bytes written.
DS2490
COMMUNICATION COMMANDS RELEASE Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte byte wIndex byte byte byte 0X00 (unused) byte size bytes preamble written. wLength 0x0000 PATH Setup Packet Encoding: bmRequestType bRequest wValue
wIndex
wLength
0x40 COMM_CMD byte byte byte byte byte byte byte 0X00 (unused) byte size bytes number couplers that need activated path target device. 0x0000 activates CRC16 generator. This command also applicable Write Write Buffer function crypto iButton write partial page page size parameter target address need accordingly. 0x40 COMM_CMD byte byte byte byte byte byte byte 0X00 (unused) byte number bytes sent device following byte preamble. This number typically identical page size. value 0x00 specifies byte page. 0x0000
WRITE SRAM PAGE Setup Packet Encoding: bmRequestType bRequest wValue
wIndex
wLength
DS2490
COMMUNICATION COMMANDS selects CRC16 generator, otherwise 8-bit assumed. This command also applicable Read Read READ PROT PAGE Buffer function crypto iButton Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte byte wIndex byte byte byte -number pages read. byte page size: log(base number bytes that considered page. Typical 32-decimal data memory status memory. Page size indicates 256-byte page. example, actual page size 3210, then Page Size parameter would need 0x05 wLength 0x0000 READ REDIRECT PAGE W/CRC Setup Packet Encoding: bmRequestType bRequest wValue
wIndex
wlength
0x40 COMM_CMD byte byte byte byte byte byte byte page number used first read attempt. byte page size: number bytes that considered page. Typical decimal data memory. Page size indicates 256byte page. 0x0000
DS2490
COMMUNICATION COMMANDS SEARCH ACCESS Setup Packet Encoding: bmRequestType 0x40 bRequest COMM_CMD wValue byte byte byte byte wIndex byte byte byte number devices. Maximum number devices discovered single command call. value 0x00 indicates that devices 1-Wire Network discovered. byte 1-Wire command: Command used addressing 1-Wire device. Valid codes: 0xF0 (Search ROM) 0xEC (Conditional Search ROM) wLength 0x0000 APPENDIX DS2490 MODE COMMANDS, SETUP PACKET ENCODING MODE COMMANDS ENABLE PULSE Setup Packet Encoding: bmRequestType bRequest wValue wIndex
wLength ENABLE SPEED CHANGE Setup Packet Encoding: bmRequestType bRequest wValue wIndex
0x40 MODE_CMD MOD_PULSE_EN byte byte byte 0x00 byte SPUE Strong pullup enabled with SPUE disabled with SPUE 0x0000
wLength
0x40 MODE_CMD MOD_SPEED_CHANGE_EN byte byte byte 0x00 byte Boolean value. Speed changes enabled with TRUE, disabled with FALSE. 0x0000
DS2490
MODE COMMANDS 1-WIRE SPEED Setup Packet Encoding: bmRequestType bRequest wValue wIndex
wLength STRONG PULLUP DURATION Setup Packet Encoding: bmRequestType bRequest wValue wIndex
0x40 MODE_CMD MOD_1WIRE_SPEED byte byte byte 0x00 byte 1-Wire speed: Code specifying communication speed 1-Wire bus. MODE CONTROL section code definition. 0x0000
wLength PULLDOWN SLEW RATE Setup Packet Encoding: bmRequestType bRequest wValue wIndex
0x40 MODE_CMD MOD_STRONG_PU_DURATION byte byte byte 0x00 byte Unsigned 8-bit binary number specifying pullup duration. MODE CONTROL section byte weighting additional format information. 0x0000
wLength
0x40 MODE_CMD MOD_PULLDOWN_SLEWRATE byte byte byte 0x00 byte Code specifying typical pulldown slew rate. MODE CONTROL section code definition. 0x0000
DS2490
MODE COMMANDS WRITE-1 TIME Setup Packet Encoding: bmRequestType bRequest wValue wIndex
wLength DSOW0 RECOVERY TIME Setup Packet Encoding: bmRequestType bRequest wValue wIndex
0x40 MODE_CMD MOD_WRITE1_LOWTIME byte byte byte 0x00 byte Code specifying Write-1 time duration. MODE CONTROL section code definition. 0x0000
0x40 MODE_CMD MOD_DSOW0_TREC byte byte 0x00
byte
wLength
byte Code specifying recovery time data sample offset Write-0. MODE CONTROL section code definition. 0x0000
APPENDIX COMMAND, COMMAND TYPE CONSTANT CODES COMMAND TYPE CODES Name CONTROL_CMD COMM_CMD MODE_CMD CONTROL COMMAND CODES Name CTL_RESET_DEVICE CTL_START_EXE CTL_RESUME_EXE CTL_HALT_EXE_IDLE CTL_HALT_EXE_DONE CTL_FLUSH_COMM_CMDS CTL_FLUSH_RCV_BUFFER CTL_FLUSH_XMT_BUFFER CTL_GET_COMM_CMDS bRequest 0x00 0x01 0x02 wValue 0x0000 0x0001 0x0002 0x0003 0x0004 0x0007 0x0008 0x0009 0x000A
DS2490
MODE COMMAND CODES Name MOD_ PULSE_EN MOD_SPEED_CHANGE_EN MOD_1WIRE_SPEED MOD_STRONG_PU_DURATION MOD_PULLDOWN_SLEWRATE (Reserved) MOD_WRITE1_LOWTIME MOD_DSOW0_TREC
wValue 0x0000 0x0001 0x0002 0x0003 0x0004 0x0005 0x0006 0x0007
DS2490
REVISION HISTORY
REVISION DATE DESCRIPTION Removed EPROM programming feature. Updated ordering info show lead-free parts only. Removed note contact factory flip chip. Deleted previous Figure Table Deleted Table Notes renumbered Notes. Updated tLOW0, tREC0, tSLOT values Figure match actual silicon. Updated tLOW1, tDSO, tHIGH1 tSLOT values Figure match actual silicon. Updated Tables match actual silicon. Updated text paragraph above Figure Some updates items required numeric updates related text sections. 10/09 maximum changed from 1200µA, VOL(SUSO) test current changed from 1mA. 9-23, 31-37, 42-50 PAGES CHANGED
12/07

DS2490 1-Wire Bridge Chip Communicates regular overdrive 1Wire® s

Top Searches for this datasheet

Other recent searches