AMBE-2000™ Vocoder Chip

User’s Manual Version 3.0

page 34

Confidential Proprietary, Subject to Change

5.4.2 Unformatted Serial Input Format

The Unformatted Input format contains 1 to 4 bits within each 16 bits serial output word. For the formats which contain more

than one bit each word the MSB of the data bits is considered first in the transmission. In Unformatted mode, the header data

from Formatted mode is dropped and each 16 bit write contains 1 to 4 coded voice data bits. The number of words that need to

be transferred into the decoder for each 20 millisecond frame will be the number of bits per frame divided by the number of bits

per word. So a system coding at 4800 bps with 3 bits per word will need to write exactly 32 ( [4800

frame.

Table 5-Q Unformatted Serial Input Data Format

Data

Control Offset

Control Data

Bits per Word

See Table 4-A

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

1 bit per Word Format

0

0

0

0

0

0

X

X

X

X

X

X

X

X

X

2 bits per Word Format

D

0

0

0

0

0

X

X

X

X

X

X

X

X

X

3 bits per Word Format

D

D

0

0

0

0

X

X

X

X

X

X

X

X

X

4 bits per Word Format

D

D

D

0

0

0

X

X

X

X

X

X

X

X

X