Designed Windows 95/98/NT Supports Windows Keys Supports Power, Sleep

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Designed Windows 95/98/NT Supports Windows Keys Supports Power, Sleep

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HT82K28A Win98 Keyboard Encoder
Designed Windows 95/98/NT Supports Windows Keys Supports Power, Sleep Wake-up Windows ACPI functions Supports Japanese, Korean Portuguese Supports Japanese DOS/V 106-key keyboard Supports code PS/2 model keyboard
Supports code PC/AT, PS/2 model 50,60 keyboards Supports code PS/2 model keyboard oscillator Phantom detection Minimal external components Pin-compatible with Holtek HT6547E-2 40-pin package
General Description
HT82K28A keyboard encoder especially designed PC/AT, PS/2 compatible machines. HT82K28A accepts keyboard inputs contains 16-character first-in-first-out buffer which data stored. inexpensive oscillator used system clock. device offers advantage simple implementation high performance cost keyboard applications.
Assignment
Rev. 1.10 July 2001
HT82K28A
Description
7~12 16~23, 13~15 Name OSC1 IO0~IO1 C0~C7 System clock input Negative power supply, ground Positive power supply Customer defined optional output lines Keyboard matrix scanning input pins Description
R0~R18 SCRL CLOCK DATA
Keyboard matrix scanning output pins connection
Synchronous clock signal. Used clock transmission data Bidirectional data transmission line
Absolute Maximum Ratings
Supply Voltage .4.75V 5.25V Storage Temperature .-55°C 125°C Input Voltage.VSS-0.3V VDD+0.3V Operating Temperature .0°C 70°C
Note: These stress ratings only. Stresses exceeding range specified under Maximum cause substantial damage device. Functional operation this device other conditions beyond those listed specification implied prolonged exposure extreme conditions affect device reliability.
Rev. 1.10
July 2001
HT82K28A
Electrical Characteristics
Symbol Parameter Operating Voltage Operating Current Input Voltage (C0~C7) Input Voltage (DATA, CLOCK) Input High Voltage Output Voltage (R0~R18) Output Voltage (DATA, CLOCK) Internal Pull-high Resistance (C0~C7) fSYS Internal Pull-high Resistance (CLOCK, DATA) System Clock Test Conditions IOL=10mA IOL=15mA Min. 4.75 Ta=25°C Typ. Max. Unit 5.25
Rev. 1.10
July 2001
HT82K28A
Functional Description
HT82K28A basic function detect press release activity transmit corresponding scan code, well make break codes system. device also accepts commands from system responds system necessary. communication between keyboard system managed through CLOCK DATA pins. keyboard begins scan pressed released keys commands from system after (Basic Assurance Test) been run. Working modes Three working modes supported HT82K28A. These setup alternate scan code command various modes described follows. Mode Supports code PS/2 model keyboards. Enters mode1 after Command issued followed Contains data stream, including start (always zero) eight data bits, parity (odd parity) stop (always one). keys typematic/make/break default. working mode changed again this mode, issuing command followed option. command more detail. Mode
Supports code PC/AT, PS/2 model
Mode
Supports code PS/2 model key-
boards.
Enters mode when command issued
followed
Contains data stream, including
start (always zero) eight data bits, parity (odd parity) stop (always one).
Buffers buffers support following functions:
16-byte FIFO buffer: stores keystrokes
scan codes.
Additional keystrokes will ignored. Response codes, FA/FE. occupy
buffer positions.
Basic assurance test following functions offered Basic Assurance Test:
Turns status indicators. Keyboard processor test. test. Turns status indicators, i.e.
LEDs.
Reports result system.
keyboards.
Enters mode after power
working mode changed command followed option byte command more details. Contains data stream, including start (always zero) eight data bits, parity (odd parity) stop (always one) keys typematic/make/break default.
Note: During BAT, activity "clock" "data" line ignored. turned beginning turned BAT. takes minimum 450ms after maximum 2.5s. response satisfactory completion response failure error. reset keyboard command will also cause keyboard execute BAT. Completion codes sent between 500ms after reset command acknowledged. After BAT, keyboard sets keys typematic make/break, sets default typematic rate delay.
Rev. 1.10
July 2001
HT82K28A
Power-on important activities take place when power first applied keyboard. first presence signal (Power-On-Reset) that resets keyboard processor. second activity running self test (Basic Assurance Test) routine.
keys except PAUSE typematic. Typematic means that keeps sending make codes held down. data report according typematic rate/delay: Default values are: delay 500ms 10.9 char/sec typematic rate delay modified with command. more keys held down, only last pressed repeats typematic rate. Typematic operation stops when last pressed released even other keys still held down. pressed held down while keyboard transmission inhibited, only first make code stored buffer overflow result typematic action. Four types supported shown: type Typematic Make/break Make Typematic/ make/break press make1 make1 make1 make1 hold make2 make2 release break break
PC-type/mode/code following table describes relationship between different computer types, working mode code sets. PS/2 PC-AT PS/2 PS/2 PS/2 mode mode mode mode mode code code code code code
mode changed between mode Keys
code
keys except PAUSE have make break code. PAUSE make code only. defaults except PAUSE make/ break/typematic. mode type changed following:
Note: "make1" send only make code. "Make2" continue sending make codes until released. nothing sent out.
code
Typematic Make/break Make Typematic/make/break configured command Time interval between phantoms time interval between continuous error codes 00/FF sent while phantom detected= 1000ms
Typematic Make/break Make Typematic/make/break
Rev. 1.10
July 2001
HT82K28A
System command table Command reset resend type make type make/break type typematic keys typematic/make/break keys make keys make/break keys typematic default default disabled enable typematic rate/delay Read select alternate scan codes Echo set/reset status indicators keyboard should respond within 20ms, except when performing executing reset command. Command description
Default disable
mode
Enable
mode
mode
Send system Clear output buffer Clear last typematic Start scanning
Send acknowledge system Clear output buffer, FIFO default types typematic rate/delay default value Clear last typematic Stop scanning wait further instruction
Invalid command
Send system further activities Note:
Read
Echo
Send system Continue scanning keyboard enabled Note: This command does need feed back
Send system Discontinue scanning byte ID-AB, byte must follow completion first byte within 500ms Resume scanning
Rev. 1.10
July 2001
HT82K28A
Resend
Send last code system Note: response
Reset
Disable keyboard Send system, keyboard acknowledges command with ensures system accepts before executing command system sets CLK=DATA=high 500ms: acceptance system issue command within 500ms period mentioned above override override, system performs enters mode (even mode
type Make keyboard responds with ACK, clears output buffer prepares receive identification identification accomplished system identifying each scan code value defined scan code set3. Only scan code set3 values valid identification type each identified value indicated command These commands sent using scan code set, affect only operation scan code set3
Select alternate scan code
Send system Clears both output buffer typematic Accept option byte
keys
keys typematic/make/break keys make keys make/break keys typematic Send system Clear output buffer keys type indicated command
Send system Discontinue scanning Wait option from system Respond with system indicator command comes from system place option, discard function then process command default after power default disable change LEDs
typematic rate/delay
default
Send system Clear output buffer default states: Default type typematic rate/delay
type FB,FC,FD
type Typematic type Make/Break
Send system Stop scanning Wait system typematic rate delay Send system rate/delay delay 4,3,2,1,0 typematic rate (always) Delay= (1+bit6,bit5) 250ms Typematic rate= 1/period .where period= (8+A) (2^B) 0.00417 .where binary value .where binary value
Rev. 1.10
July 2001
HT82K28A
b4~b0 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 01111
Default
Typematic rate 30.0 26.7 24.0 21.8 20.0 18.5 17.1 16.0 15.0 13.3 12.0 10.9 10.0
b4~b0 10000 10001 10010 10011 10100 10101 10110 10111 11000 11001 11010 11011 11100 11101 11110 11111
Typematic rate
Resend
issues when there parity error transmission.
Data communications
Data output
delay: 500ms± typematic rate=10.9 characters/sec±
CLK=0, transmission (keyboard inhibited). CLK=1, DATA=0, transmission (system request send). CLK=1, DATA=1, transmission permitted. Data will valid before trailing edge beyond leading edge clock. checks clock line active level least every 60ms. line contention occurs (system brings clock before tenth clock), clock=data=high.
Data input
Commands system keyboard detect error/overrun (set AB,83: keyboard completion failure Echo Acknowledge Resend Keyboard detects overrun (set
Acknowledge
(Keyboard) receives valid input except (echo) resend (FE) then send system first. command then send back system. command then send last code system. there interrupt while sending discards accepts command from system processes 00/FF: overrun keyboard detects overrun error, sends overrun error code system. mode mode 2,3:
Rev. 1.10
system overrides clock line least 60ms keyboard checks state clock line intervals more than 10ms system request-to-send detected, keyboard counts data bits. Data will valid before rising edge beyond falling edge After 10th bit, keyboard checks active level "data" line. line active forced inactive, counts more bit. Note: This action signals system that keyboard received data. Upon reception this signal, system returns ready state, which accept keyboard outputs goes inhibit state until ready.
keyboard "data" line found inactive level following 10th bit, frame error occurred, keyboard continues count until "data" line becomes active. keyboard then makes "data" line inactive sends Resend.
July 2001
HT82K28A
Data stream Mode 1,2,3 b10: b11: start always data data data data data data data data parity (odd par) stop always
Note: parity either data bits, plus parity bit, always have number
Rev. 1.10
July 2001
HT82K28A
code Number Make/Break Code Number Make/Break Code
Rev. 1.10
July 2001
HT82K28A
code Base Case Left-Shift Right-Shift Shift+Num When both shift keys held down: Both Shift number 52/E0 Number Number Base +Left-Shift Both Shift +Left-Shift Lock
+Right-Shift
when both shift keys held down: number Number Base
+Right-Shift 54/D4
Number Base +Ctrl This typematic, associated scan codes occur make code. ACPI Power Sleep Wake
Rev. 1.10
Make
Break
Windows Virtual
July 2001
HT82K28A
code Number Make/Break Code Number Make/Break Code
Rev. 1.10
July 2001
HT82K28A
code Number Base Case Shift+Num Left-Shift Right-Shift Lock
When both shift keys held down: number Number Base
Both Shift +Right-Shift
When both shift keys held down: number Number Base
+Left-Shift Both Shift +Shift +Ctrl
+Alt
Number Base +Ctrl Note: this typematic, associated scan codes occur make key. ACPI Power Sleep Wake Make Break Windows Virtual
Rev. 1.10
July 2001
HT82K28A
code Make/ Break Code Note Default State Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Make/Break Make/ Break Code Note Default State Make/Break Make/Break Make/Break Typematic Make Only Make Only Make Only Typematic Typematic Make Only Make Only Typematic Typematic Make Only Make Only Typematic Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only
Rev. 1.10
July 2001
HT82K28A
Make/ Break Code Note Default State Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Make/Break Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Typematic Make/ Break Code Note Default State Make Only Typematic Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make Only Make/Break Make/Break Make/Break
Different from code
Rev. 1.10
July 2001
HT82K28A
Timing Diagrams
Data output
itio llin itio ilia ilia
Keyboard data input
itio ilia
Rev. 1.10
July 2001
HT82K28A
Application Circuits
Rev. 1.10
July 2001
HT82K28A
Standard Holtek Win98 keyboard K129 K109 R-WIN PRINT POWER SLEEP INSERT HOME SLEEP L-ALT ENTER LOCK SPACE Arrow ENTER R-SHF K107 L-SHF L-WIN POWER LOCK PAUSE LOCK WAKE K130
L-CTRL WAKE-UP R-CTRL K131 K132 K133 R-ALT DOWN Arrow RIGHT Arrow LEFT Arrow
Rev. 1.10
July 2001
HT82K28A
above code according Microsoft specification except following keys. Code Make/Break Code Make/Break Code Make/Break
Rev. 1.10
July 2001
HT82K28A
Holtek Semiconductor Inc. (Headquarters) No.3, Creation Science-based Industrial Park, Hsinchu, Taiwan Tel: 886-3-563-1999 Fax: 886-3-563-1189 Holtek Semiconductor Inc. (Taipei Office) 11F, No.576, Sec.7 Chung Hsiao Rd., Taipei, Taiwan Tel: 886-2-2782-9635 Fax: 886-2-2782-9636 Fax: 886-2-2782-7128 (International sales hotline) Holtek Semiconductor (Hong Kong) Ltd. RM.711, Tower Cheung Plaza, Cheung Rd., Kowloon, Hong Kong Tel: 852-2-745-8288 Fax: 852-2-742-8657 Holtek Semiconductor (Shanghai) Ltd. Floor, Building No.889, Shan Rd., Shanghai, China Tel: 021-6485-5560 Fax: 021-6485-0313 Holmate Technology Corp. 48531 Warm Springs Boulevard, Suite 413, Fremont, 94539 Tel: 510-252-9880 Fax: 510-252-9885 Copyright 2001 HOLTEK SEMICONDUCTOR INC. information appearing this Data Sheet believed accurate time publication. However, Holtek assumes responsibility arising from specifications described. applications mentioned herein used solely purpose illustration Holtek makes warranty representation that such applications will suitable without further modification, recommends products application that present risk human life malfunction otherwise. Holtek reserves right alter products without prior notification. most up-to-date information, please visit site http://www.holtek.com.tw.
Rev. 1.10
July 2001

Designed Windows 95/98/NT Supports Windows Keys Supports Power, Sleep

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