HT82K628A

Rev. 1.60

4

April 16, 2004

F3H

- Set Typematic Rate/Delay

The host issues the Set Typematic Rate/Delay com-

mand to change the typematic rate and delay. The

HT82K628A responds to the command with ACK, stops

scanning and waits for the system to issue the rate/de-

lay value byte. The HT82K628A responds to the value

byte with another ACK, sets the rate and delay to the

value indicated, and continues scanning (if it was previ-

ously enabled). Bit6 and 5 indicate the delay, and bits 4,

3, 2, 1 and 0 indicate the rate. Bit7 is always 0. The delay

is equal to 1 plus the binary value bit 6 and 5, multiplied

by 250ms

±20%.

The period (interval from one typematic output to the

next) is determined by the following equation:

Period = (8+A)*(2^B)*0.00417 seconds.

Where:

A = binary value of bits 2, 1, and 0.

B = binary value of bits 4, and 3.

The typematic rate is 1 for each period and are listed as

follows:

Bit

Typematic

Rate

± 20%

Bit

Typematic

Rate

± 20%

00000

30.0

10000

7.5

00001

26.7

10001

6.7

00010

24.0

10010

6.0

00011

21.8

10011

5.5

00100

20.0

10100

5.0

00101

18.5

10101

4.6

00110

17.1

10110

4.3

00111

16.0

10111

4.0

01000

15.0

11000

3.7

01001

13.3

11001

3.3

01010

12.0

11010

3.0

01011

10.9

11011

2.7

01100

10.0

11100

2.5

01101

9.2

11101

2.3

01110

8.0

11110

2.1

01111

8.0

11111

2.0

The default values for the HT82K628A are as follows:

Typematic rate= 10.9 characters per second

± 20%

Delay = 500ms

±20%

The execution of this command stops without change to

the existing rate if another command is received instead

of the rate/delay value byte.

F4H

- Enable

Upon receipt of this command, the HT82K628A will re-

spond with ACK, clears its output buffer, clears the last

typematic key, and starts scanning.

F5H

- Default Disable

The Default Disable command resets all conditions to

the power on default states. The HT82K628A will re-

spond with ACK, clears its output buffer, sets the default

key types (scan code set 3 operation only) and

typematic rate/delay, and clears the last typematic key.

The HT82K628A then stops scanning and awaits further

command.

F6H

- Set Default

The Set Default command resets all conditions to the

power on default states. The HT82K628A will respond

with ACK, clears its output buffer, sets the default key

types (scan code set 3 operation only) and typematic

rate/delay, and clears the last typematic key then contin-

ues scanning.

F7H, F8H, F9H, FAH

- Set All Keys

These commands instruct the HT82K628A to set all

keys to the type listed below:

Hex Value

Command

F7

Set All Keys-Typematic

F8

Set All Keys-Make/Break

F9

Set All Keys-Make

FA

Set All Keys-Typematic/Make/Break

The HT82K628A will respond with ACK, clears its output

buffer, sets all keys to the type indicated by this com-

mand, and continues scanning (if it was previously en-

abled). Although these commands can be sent using

any code set, they affect only scan code set 3 operation.

FBH, FCH, FDH

- Set Key Type

These commands instruct the HT82K628A to set indi-

vidual keys to the type listed below:

Hex Value

Command

FB

Set Key Type-Typematic

FC

Set Key Type-Make/Break

FD

Set Key Type-Make

The HT82K628A will respond with ACK, clears its output

buffer and prepares to receive key identification. Key

identification is accomplished by the host identifying

each key by its scan code value as defined in scan code

set 3. Only scan code set 3 values are valid for key iden-

tification. The type of each identified key is set to the

value indicated by the command. Although these com-

mands can be sent using any code set, they affect only

scan code set 3 operation.