HT6221A datasheet(4/19 Pages) HOLTEK

4 / 19 page

HT6220A/HT6221A/HT6221B/HT6222A

Rev. 1.10

June 1, 2010

Functional Description

Keyboard Scan

The devices remain in the halt mode during the standby

state (at this time, the oscillator stops, and the standby

current<1

mA). The HT6220A consists of 30 active keys,

HT6221A has 32 active keys, HT6221B has 48 active

keys, and the HT6222A has 64 active keys. The key-

board forms of the devices are shown below.

· The HT6220A keyboard form

· The HT6221A keyboard form

· The HT6221B keyboard form

· The HT6222A keyboard form

When one of the keys (30, 32, 48 or 64 keys) is triggered

for over 36ms, the oscillator is enabled and the chip is acti-

vated. If the key is pressed and held for 108ms or less, the

108ms transmission codes are enabled and comprised of

a header code (9ms), an off code (4.5ms), low byte ad-

dress codes (9ms~18ms), high byte address codes

(9ms~18ms), 8-bit data codes (9ms~18ms), and the in-

verse codes of the 8-bit data codes (18ms~9ms). After the

pressed key is held for 108ms, if the key is still held down,

the transmission codes turn out to be a composition of

header (9ms) and off codes (2.24ms) only.

To avoid mistakes made by keyboard scanning or simul-

taneous two-key inputs (except for the three double-key

active functions (K21+K22, K21+K23, and K21+K24),

the devices are facilitated with 36ms starting time.

The HT6221A/HT6221B/HT6222A also provide three

double-key active functions (K21+K22, K21+K23, and

K21+K24) for tape deck recording operations. The dou-

ble-key operation rules are shown in timing 4 and timing

Transmission Codes

The transmission codes of the devices consist of a 9ms

header code, a 4.5ms off code, 16-bit address codes

(18ms~36ms), 9ms~18ms 8-bit data codes, and the in-

verse code of the 8-bit data codes. The following is an il-

lustration of the transmission codes.

C 1

R 1

R 2

R 3

R 4

R 5

R 6

R 7

R 8

K 1

K 2

K 3

K 4

K 3 3

K 3 4

K 3 5

K 3 6

K 5

K 6

K 7

K 8

K 3 7

K 3 8

K 3 9

K 4 0

K 9

K 1 0

K 1 1

K 1 2

K 4 1

K 4 2

K 4 3

K 4 4

K 1 3

K 1 4

K 1 5

K 1 6

K 4 5

K 4 6

K 4 7

K 4 8

K 1 7

K 1 8

K 1 9

K 2 0

K 4 9

K 5 0

K 5 1

K 5 2

K 2 1

K 2 2

K 2 3

K 2 4

K 5 3

K 5 4

K 5 5

K 5 6

K 2 9

K 3 0

K 3 1

K 3 2

K 6 1

K 6 2

K 6 3

K 6 4

K 2 5

K 2 6

K 2 7

K 2 8

K 5 7

K 5 8

K 5 9

K 6 0

C 2

C 3

C 4

C 5

C 6

C 7

C 8

C 1

C 2

C 3

C 4

R 1

R 2

R 3

R 4

C 5

C 6

C 7

C 8

K 1

K 2

K 3

K 4

K 5

K 6

K 7

K 8

K 9

K 1 0

K 1 1

K 1 2

K 1 3

K 1 4

K 1 5

K 1 6

K 1 7

K 1 8

K 1 9

K 2 0

K 2 1

K 2 2

K 2 3

K 2 4

K 2 5

K 2 6

K 2 7

K 2 8

K 2 9

K 3 0

K 3 1

K 3 2

D O U T

I R C

K e y - i n

( K 1 ~ K 6 4 )

3 6 m s m i n .

9 m s

4 5 m s ~ 6 3 m s

1 0 8 m s

( A 0 ~ A 1 5 + D 0 ~ D 7 + D 0 ~ D 7 )

3 8 k H z ,

3 3 % d u t y c a r r i e r

9 m s

2 . 2 4 m s

9 m s

K e y E n a b l e s

F o s c = 4 5 5 k H z

4 . 5 m s

0 . 5 6 m s

Timing 1. Output Format for the DOUT

C 1

C 2

C 3

C 4

R 1

R 2

R 3

R 4

R 5

R 6

K 1

K 2

K 3

K 4

K 3 3

K 3 4

K 5

K 6

K 7

K 8

K 3 7

K 3 8

K 9

K 1 0

K 1 1

K 1 2

K 4 1

K 4 2

K 1 3

K 1 4

K 1 5

K 1 6

K 4 5

K 4 6

C 5

K 1 7

K 1 8

K 1 9

K 2 0

K 4 9

K 5 0

C 1

C 2

C 3

C 4

R 1

R 2

R 3

R 4

R 5

R 6

C 5

C 6

C 7

C 8

K 1

K 2

K 3

K 4

K 3 3

K 3 4

K 5

K 6

K 7

K 8

K 3 7

K 3 8

K 9

K 1 0

K 1 1

K 1 2

K 4 1

K 4 2

K 1 3

K 1 4

K 1 5

K 1 6

K 4 5

K 4 6

K 1 7

K 1 8

K 1 9

K 2 0

K 4 9

K 5 0

K 2 1

K 2 2

K 2 3

K 2 4

K 5 3

K 5 4

K 2 5

K 2 6

K 2 7

K 2 8

K 5 7

K 5 8

K 2 9

K 3 0

K 3 1

K 3 2

K 6 1

K 6 2

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