HT82K28A 데이터 시트보기 (PDF) - Holtek Semiconductor

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HT82K28A

Win98 Keyboard Encoder

Holtek Semiconductor 

HT82K28A

Command description

· Default disable - F5

¨ Send an acknowledge FA to the system

¨ Clear its output buffer, FIFO

¨ Set the default key types

¨ Set typematic rate/delay as default value

¨ Clear the last typematic key

¨ Stop scanning and wait for further instruction

· Echo - EE

¨ Send an EE to the system

¨ Continue scanning if the keyboard is enabled

Note: This command does not need to feed

back the ACK

· Enable - F4

¨ Send an ACK to the system

¨ Clear output buffer

¨ Clear the last typematic key

¨ Start scanning

· Invalid command

¨ Send an FE to the system

¨ No further activities

Note: No ACK

· Read ID - F2

¨ Send an ACK to the system

¨ Discontinue scanning

¨ 2 byte ID-AB, 83

The 2nd byte must follow the completion of the first

byte within 500ms

¨ Resume scanning

· Resend - FE

¨ Send the last code to the system

Note: * No FA response

· Reset - FF

¨ Disable keyboard

¨ Send an ACK to the system, the keyboard acknowl-

edges the command with an ACK and ensures the

system accepts the ACK before executing the com-

mand

¨ The system sets CLK=DATA=high for 500ms: ac-

ceptance of ACK

¨ The system can issue any command to the KB

within the 500ms period mentioned above to over-

ride FF

¨ If no override, the system performs its BAT and en-

ters mode 2 (even if it is set to be mode 3)

· Select alternate scan code - F0

¨ Send an ACK to the system

¨ Clears both output buffer and the typematic key

¨ Accept option byte

· Set all keys - F7, F8, F9, FA

¨ FA: Set all keys to typematic/make/break

¨ F9: Set all keys to make

¨ F8: Set all keys to make/break

¨ F7: Set all keys to typematic

¨ Send an ACK to the system

¨ Clear output buffer

¨ Set all keys to the type indicated by the command

· Set default - F6

¨ Send an ACK to the system

¨ Clear the output buffer

¨ Set to default key states: Default key type typematic

rate/delay

· Set key type - FB,FC,FD

¨ FB : Set key type - Typematic

¨ FC : Set key type - Make/Break

¨ FD : Set key type - Make

¨ The keyboard responds with ACK, clears its output

buffer and prepares to receive key identification

¨ Key identification is accomplished by the system

identifying each key by its scan code value as de-

fined in scan code set3.

¨ Only scan code set3 values are valid for key identifi-

cation

¨ The type of each identified key is set to the value in-

dicated by the command

¨ These commands can be sent using any scan code

set, but affect only the operation of scan code set3

· Set LED - ED

¨ Send ACK to the system

¨ Discontinue scanning

¨ Wait for the option from the system

¨ Respond with ACK to the system

¨ Set indicator

¨ If command comes from the system in place of op-

tion, discard the set LED function and then process

the new command

¨ LED default after power on - all off

¨ Set default disable - do not change the LEDs

· Set typematic rate/delay - F3

¨ Send an ACK to the system

¨ Stop scanning

¨ Wait for the system typematic rate and delay

¨ Send an ACK to the system

¨ Set rate/delay

¨ Bit 6,5 delay

¨ Bit 4,3,2,1,0 typematic rate

Rev. 1.30

5

June 27, 2002

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