Decoder timing

HT604L/HT614/HT692

Rev. 1.10

4

January 24, 2003

Functional Description

Operation

The 3

tions of address and data pins in different packages. It is

paired with the 3

ceive data transmitted by the encoders and interpret the

first N bits of the code period as address and the last

18

-N bits as data (where N is the address code num-

ber). A signal on the DIN pin then activates the oscillator

which in turns decodes the incoming address and data.

The decoders will check the received address twice

continuously. If all the received address codes match

the contents of the decoder

¢s local address, the 18-N

bits of data are decoded to activate the output pins, and

the VT pin is set high to indicate a valid transmission.

That will last until the address code is incorrect or no sig-

nal has been received. The output of the VT pin is high

only when the transmission is valid. Otherwise it is al-

ways low.

Output Type

There are two types of output to select from:

The data outputs follow the encoder during a valid

transmission and then reset.

The data outputs follow the encoder during a valid

transmission, and are then latched in this state until

the next valid transmission occurs.

Flowchart

Note: The oscillator is disabled in the standby state

and activated as long as a logic

²high² signal

is applied to the DIN pin. i.e., the DIN should

be kept

²low² if there is no signal input.

Y e s

C o d e i n ?

S t o r e d a t a

N o

Y e s

N o

N o

N o

Y e s

S t a n d b y m o d e

D i s a b l e V T &

i g n o r e t h e r e s t o f

t h i s w o r d

Y e s

N o

Y e s

A d d r e s s o r

d a t a e r r o r ?

L a t c h / M o m e n t a r y

d a t a t o o u t p u t &

a c t i v a t e V T

A d d r e s s b i t s

m a t c h e d ?

M a t c h

p r e v i o u s s t o r e d

d a t a ?

2 t i m e s

o f c h e c k i n g

c o m p l e t e d ?

P o w e r o n

2

c l o c k s

1 4

3 w o r d s

3 w o r d s

E n c o d e r

D a t a O u t

T r a n s m i t t e d

C o n t i n u o u s l y

< 1 w o r d

E n c o d e r

T r a n s m i s s i o n

E n a b l e

c h e c k

D e c o d e r V T

L a t c h e d

D a t a O u t

M o m e n t a r y

D a t a O u t

c h e c k

1 / 2 c l o c k p e r i o d

1 / 2 c l o c k p e r i o d

2 w o r d s

2

c l o c k s

1 4