mt90502ag2 Zarlink Semiconductor, mt90502ag2 Datasheet - Page 32

• Manufacturer Part Number: mt90502ag2
• Description: Multi-channel Aal2 Sar
• Manufacturer: Zarlink Semiconductor

It is recommended that b6 of PCM padding bytes be 1 - this is in-line
with the requirement that the padding buffers contain all low energy
samples, u-law max value of 471 out of 8159 and A-law max value of
252 out of 4096 - and that ADPCM samples be placed in the low bits.
This will allow the decompressor to differentiate PCM padding bytes
from ADPCM samples, in order to bypass the decompressor during a
silence period.
Format of ADPCM Samples in low bits
Format of ADCM Samples in high bits
PCM[7]
Format of PCM Padding Samples in
b7
b7
b7
b7
b7
b7
b7
b7
b7
16 kbps
1
1
1
1
(with Decompressor reset)
(with Decompressor reset)
24 kbps
ADPCM 40 kbps
ADPCM only time slots
32 kbps
b6
b6
b6
b6
b6
b6
b6
b6
b6
0
0
0
0
1
b5
b5
b5
b5
b5
b5
b5
b5
b5
1
0
0
0
1
b4
b4
b4
b4
b4
b4
b4
b4
b4
1
0
0
1
0
ADPCM 40 kbps
PCM[5:0]
b3
b3
b3
b3
b3
b3
b3
b3
b3
1
0
1
0
0
Figure 7 - PCM/ADPCM RX Data Format A
(without Auto PCM-ADPCM Switching)
b2
b2
32 kbps
b2
b2
b2
b2
b2
b2
b2
1
1
0
0
0
Format A for RX xxPCM Samples
24 kbps
b1
b1
b1
b1
16 kbps
b1
b1
b1
b1
b1
0
0
0
0
Zarlink Semiconductor Inc.
b0
b0
b0
b0
b0
b0
b0
b0
b0
1
1
1
1
MT90502
32
Format of ADPCM Samples in high bits
Format of ADPCM Samples in low bits
Note that switching between ADPCM and
PCM requires software intervention when
using Format A
b7
b7
b7
b7
b7
b7
b7
b7
16 kbps
b7
(no Decompressor reset)
(no Decompressor reset)
0
0
0
0
Format of PCM samples
24 kbps
ADPCM 40 kbps
b6
b6
b6
b6
b6
b6
32 kbps
b6
b6
b6
0
0
0
0
b5
b5
b5
b5
b5
b5
b5
b5
b5
1
0
0
0
1
b4
b4
b4
b4
b4
b4
b4
b4
b4
1
0
0
1
0
PCM
ADPCM 40 kbps
b3
b3
b3
b3
b3
b3
b3
b3
b3
1
0
1
0
0
b2
b2
32 kbps
b2
b2
b2
b2
b2
b2
b2
1
1
0
0
0
24 kbps
b1
b1
b1
b1
16 kbps
b1
b1
b1
b1
b1
0
0
0
0
Data Sheet
b0
b0
b0
b0
b0
b0
b0
b0
b0
0
0
0
0