HT82K629A datasheet(5/23 Pages) HOLTEK

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HT82K629A

Rev. 1.30

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

HT82K629A responds to the command with ACK, stops

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

lay value byte. The HT82K629A 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). Bits 6 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, mul-

tiplied 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 HT82K629A are as follows:

Typematic rate= 10.9 characters per second

± 20%

Delay = 500ms

±20%

The execution of this command stops without changes

to the existing rate if another command is received in-

stead of the rate/delay value byte.

F4H

- Enable

Upon receipt of this command, the HT82K629A 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 HT82K629A will

respond with ACK, clears its output buffer, sets the de-

fault typematic rate/delay, and clears the last typematic

key. The HT82K629A then stops scanning and awaits

further command.

F6H

- Set Default

The Set Default command resets all conditions to the

power on default states. The HT82K629A will respond

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

typematic rate/delay, and clears the last typematic key

then continues scanning.

F7H, F8H, F9H, FAH

- Set All Keys

Since HT82K629A do not support keyboard code set 3

format, so it will not acknowledge the command but re-

turns a Resend command and continues in its previous

scanning state.

FBH, FCH, FDH

- Set Key Type

Since HT82K629A do not support keyboard code set 3

format, so it will not acknowledge the command but re-

turns a Resend command and continues in its previous

scanning state.

FEH

- Resend

The host sends this command when it detects an error in

any transmission from the HT82K629A. It is sent only af-

ter a data transmission and before the host allows the

next data output. When a Resend is received, the

HT82K629A sends the previous output again (unless

the previous output was Resent, in which case the

HT82K629A sends the last byte before the Resend

command).

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