HT6221/HT6222

Multi-Purpose Encoders

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When one of the keys (32 or 64 keys) is triggered for over 36ms, the oscillator is enabled and the chip is activated. 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 address codes (9ms ~ 18ms), high byte address codes (9ms~18ms), 8-bit data codes (9ms ~ 18ms), and

the inverse 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 (2.5ms) only.

To avoid mistakes made by keyboard scanning or simultaneous two-key inputs (except for the three double-key active functions

(K21 + K22, K21+K23, and K21+K24), the HT6222 are facilitated with 36ms starting time.

The HT6221/HT6222 also provide three double-key active functions (K21+K22, K21+K23, and K21+K24) for tape deck recording

operations. The double-key operation rules are shown in timing 4 and timing 6.

Transmission codes

The transmission codes of the HT6221/6222 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 inverse code of the 8-bit data codes. The following is an illustration of the transmission

codes: