BT8954 CONEXANT [Conexant Systems, Inc], BT8954 Datasheet - Page 81

• Manufacturer Part Number: BT8954
• Description: VOICE PAIR GAIN FRAMER
• Manufacturer: CONEXANT [Conexant Systems, Inc]

Bt8954
Voice Pair Gain Framer
PFRAME_LEN[7:0]
PCM_FREQ
ENC_FSYNC
COMPRESSED
NUM_CHAN[4:0]
N8954DSC
0xF0—PCM Frame Length (PFRAME_LEN)
0xF1—PCM Format (PCM_FORMAT1)
PCM_FREQ
7
7
ENC_FSYNC
PCM Frame Length contains the number of bits in one 125 s PCM frame less 1. The selected
value is given by
PCMCKI frequency.
Indicates if PCMF[6:1] contains encoded PCM frame syncs. If ENC_FSYNC is 1, PCMF[6:1]
is encoded.
exceeds 18, the total number of available PCMF pins. For example, if NUM_CHAN = 10 and
COMPRESSED = 1, ENC_FSYNC must be 1, since 20 (the number of PCMF strobes needed
to represent 20 compressed voice channels) is greater than 18, which is the number of available
PCMF pins.
Indicates if each time slot carries one 64 kbps clear voice channel or carries two 32 kbps
compressed voice channels.
Number of used PCM time slots. Satisfies the following inequality:
8 x (# time slots in 125 s PCM frame) –1
if PCM_FREQ (PCM_FORMAT1; addr 0xF1) = 0,
PFRAME_LEN = 8 x 32 –1 = 255
if PCM_FREQ (PCM_FORMAT1; 0xF1) = 1,
PFRAME_LEN = 8 x 24–1 = 191
ENC_FSYNC must be programmed as 1 if the number of compressed voice channels
6
6
COMPRESSED
5
5
0 : f
1 : f
0 = PCMF[6:1] is decoded
1 = Encoded PCMF[6:1]
0 = All channels are clear
1 = All channels are compressed
1 <= NUM_CHAN[4:0] <= 18
PCMCKI
PCMCKI
4
4
PFRAME_LEN[7:0]
= 2.048 MHz
= 1.536 MHz
Conexant
3
3
NUM_CHAN[4:0]
2
2
1
1
4.12 PCM Formatter
4.0 Registers
0
0
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