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Designed Windows 95/98/NT Supports Windows Keys Supports Power, Sleep
Top Searches for this datasheetHT82K28A 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 Other recent searchesX24C44 - X24C44 X24C44 Datasheet SN74LV374A - SN74LV374A SN74LV374A Datasheet SN54LV374A - SN54LV374A SN54LV374A Datasheet RF2416 - RF2416 RF2416 Datasheet NCV33275 - NCV33275 NCV33275 Datasheet NA28F - NA28F NA28F Datasheet LTC1291 - LTC1291 LTC1291 Datasheet LM2653EVAL - LM2653EVAL LM2653EVAL Datasheet DS1666 - DS1666 DS1666 Datasheet DC394 - DC394 DC394 Datasheet LT1619 - LT1619 LT1619 Datasheet AVF16 - AVF16 AVF16 Datasheet
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