Normal operation

The HT6P20 encodes and transmits address/data to a decoder upon receipt of a trigger signal. The

address codes of the HT6P20A are always transmitted as long as power (VDD) is supplied. The trans-

mission function of the HT6P20B/D is enabled by the D0~D7 pins (active low). The following is the

transmission timing of the HT6P20:

A complete code word of the HT6P20D consists of 3 periods as shown below.

The HT6P20A/B/D detects the logic state of the internal programmed address and the external data

pins, and then transmits the detected information during the code period. Each address/data bit can be

set to one of the following two logic states:

HT6P20

6

May 2, 2000

" O ne"

" Z er o"

f o sc

A ddr es s /

Da t a b i t

ant i - c ode p e r i od

(4 b i t s )

p ilo t p e r io d

( 2 3 cl o cks)

addr es s c ode per i o d

dat a c ode p e r i od

1/3 b i t

( A 0 ~ A 19 , 6 0 cl o cks)

( D 3 ~ D 0 , 12 cl o cks)

00

11

fo s c

DO UT

1 c l o c k

A complete code word for the HT6P20D

E n c oder

DO UT

< 1 w or d

D 0 ~ D 7

> 1 w or d

Transmission timing