4.0 Registers
RS8953B/8953SPB
4.6 PCM Formatter
HDSL Channel Unit
MF_LEN[5:0]
PCM Multiframe Length—Contains the number of PCM frames in one PCM multiframe, in
the range of 1 to 64 frames. A value of zero selects one frame per multiframe, which causes
TMSYNC and RMSYNC to operate at the PCM frame rate.
0xC7—PCM Multiframes per HDSL Frame (MF_CNT)
7
6
5
4
3
2
1
0
—
—
MF_CNT[5:0]
MF_CNT[5:0]
PCM Multiframes per HDSL Frame—Contains the number of PCM multiframes in one HDSL
6 ms frame, in the range of 1 to 64 multiframes. A value of zero selects one multiframe per
HDSL frame. MF_CNT operates in conjunction with FRAME_LEN and MF_LEN to create
transmit and receive PCM 6 ms timebases which are needed to perform transmit bit stuffing
and DPLL receive clock recovery. The RS8953B requires the product of MF_LEN and
MF_CNT to always equal 48 to match the number of HDSL payload blocks in an HDSL
frame. For example:
PCM Multiframe
E1 =16 frames
SF = 12 frames
ESF = 24 frames
Unframed = 1 frame
MF_LEN[5:0] MF_CNT[5:0]
Product
15 (0x0F)
11 (0x0B)
23 (0x17)
0 (0x00)
2 (0x02)
3 (0x03)
1 (0x01)
47 (0x2F)
16 x 3 = 48
12 x 4 = 48
24 x 2 = 48
1 x 48 = 48
0xC8—PCM Frame Length (FRAME_LEN_LO)
7
6
5
4
3
2
1
0
FRAME_LEN[7:0]
0xC9—PCM Frame Length (FRAME_LEN_HI)
7
6
5
4
3
2
1
0
—
—
—
—
—
—
—
FRAME_LEN[8]
FRAME_LEN[8:0] PCM Frame Length—Contains the number of bits in one PCM frame, in the range of 16 to
512 bits. A value of 255 selects 256 bit PCM frame length. The selected value includes
payload (number of timeslots x 8) and framing bits. For example, FRAME_LEN value equals
192 (0xC0) to select a 193-bit T1 frame.
4-28
Conexant
N8953BDSB
CONEXANT [ CONEXANT SYSTEMS, INC ]
