HT9480 datasheet(22/47 Pages) HOLTEK

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HT9480

Rev. 1.20

July 31, 2002

Message data transfer

The decoder outputs a deformatted address word and

message words upon receipt of a valid call. The mes-

sage data to be transferred is organized into 8-bit words

and transferred through the parallel pager data address

(1FH) byte by byte. When a call word starts, the decoder

generates a data ready interrupt simultaneously and

runs the processing subroutine. The subroutine should

read out the word in the pager data address (1FH) be-

fore the next call word comes in, i.e., the word should be

read in 4mS at 512/1200 bit data rate and in 2mS at a

2400 bit data rate. Otherwise, the data in 1FH is overrid-

den by the next word.

Termination word format

Successful call termination occurs by the reception of a

valid address code-word with less than 2 bit errors on

the decoder output register.

Unsuccessful termination occurs when sync is not de-

tected.

Termination word format:

Bit7

Bit6

Bit5

Bit4

Bit3

Bit2

Bit1

Bit0

Error

Flag

0000100

Call data output format

The HT9480 automatically converts message

code-words received in numeric or alphanumeric format

into ASCII format. Depending on SPF09 and the func-

tion bit setting in the received address code-word a con-

version takes place as shown in the following table.

Function Bits

Message

Format

SPF 09

Bit 20

Bit 21

numeric

alpha-numeric

L a s t M E S S A G E W O R D

T E R M I N A T I O N W O R D

C a l l d a t a

D a t a R e a d y D R

1 . H [ 0 : 7 ]

S e t 1 E H b i t 7 t o h i g h

D a t a R e a d y I N T

A D D R E S S C O D E W O R D

D a t a R e a d y I N T

1 s t M E S S A G E C O D E W O R D

6 b i t s

2 n d M E S S A G E C O D E W O R D

8 b i t s

6 b i t s

D a t a R e a d y D R

4 9 9 8 m s < T < 6 6 6 4 m s

1 3 m s

1 2 0 0 b p s N u m e r i c

1 . H [ 0 : 7 ]

S e t 1 E H b i t 7 t o h i g h

D a t a R e a d y I N T

D a t a R e a d y D R

A D D R E S S W O R D

1 s t M E S S A G E W O R D

C T

Numeric message data transfer

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