ht82k28a Holtek Semiconductor Inc., ht82k28a Datasheet - Page 5

• Manufacturer Part Number: ht82k28a
• Description: Ht82k28a -- Win98 Keyboard Encoder Restricted Products
• Manufacturer: Holtek Semiconductor Inc.

Command description
Rev. 1.30
Default disable
Echo
Enable
Invalid command
Read ID
Resend
Reset
Select alternate scan code
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
Send an EE to the system
Continue scanning if the keyboard is enabled
Note:
Send an ACK to the system
Clear output buffer
Clear the last typematic key
Start scanning
Send an FE to the system
No further activities
Note:
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
Send the last code to the system
Note:
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 500 s: ac-
ceptance of ACK
The system can issue any command to the KB
within the 500 s 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)
Send an ACK to the system
Clears both output buffer and the typematic key
Accept option byte
EE
FF
F4
This command does not need to feed
No ACK
FE
* No FA response
back the ACK
F2
F5
F0
5
Set all keys
Set default
Set key type
Set LED
Set typematic rate/delay
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
Send an ACK to the system
Clear the output buffer
Set to default key states: Default key type typematic
rate/delay
FB : Set key type
FC : Set key type
FD : Set key type
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
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
Set default disable
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
ED
F6
F7, F8, F9, FA
FB,FC,FD
Typematic
Make/Break
Make
do not change the LEDs
F3
all off
HT82K28A
June 27, 2002