RS8953 Conexant Systems, Inc., RS8953 Datasheet - Page 99

• Manufacturer Part Number: RS8953
• Description: High-bit-rate Digital Subscriber Line (hdsl) Channel unit
• Manufacturer: Conexant Systems, Inc.

RS8953B/8953SPB
HDSL Channel Unit
HFRAME3_LEN[8:0]
SYNC_WORD_A[6:0]
SYNC_WORD_B[6:0]
N8953BDSB
0xFB—HDSL Frame Length (HFRAME3_LEN_HI)
0xCB—SYNC Word A (SYNC_WORD_A)
0xCC—SYNC Word B (SYNC_WORD_B)
0xCD—RX FIFO Water Level (RFIFO_WL_LO)
—
—
—
7
7
7
7
HDSL Payload Block Length—Contains the number of BCLK3 bits, in the range of 16 to 512,
that are transmitted and received in an HDSL payload block for Channel 3.
lengths are not close to the same value, RFIFO errors will probably occur. For this reason, we
do not recommend different values for the HDSL frame length.
word. Transmit SYNC word magnitude bits are forced to 0. SYNC_WORD_A[0] is the sign
bit of the first transmit quat. Sign precedes magnitude on the transmit data (TDATn) output.
The receive framer searches HDSL data (RDATn) for patterns matching SYNC_WORD_A
and/or SYNC_WORD_B according to the criteria selected in FRAMER_EN [RCMD_1; addr
0x60].
performs the same function as SYNC_WORD_A (see above). SYNC_WORD_B is provided
for 2T1 applications that use different SYNC patterns on each HDSL channel for loop
identification purposes. Transmit selection of SYNC word A or B is programmed by
SYNC_SEL [TCMD_1; addr 0x06].
SYNC Word A—Holds the 7 sign bits (+/–) of the 7-quat (14-bit) transmit and receive SYNC
SYNC Word B—Holds the 7 sign bits (+/–) of the transmit and receive SYNC word. It
—
In theory, the HDSL frame length can be different for each loop. But if the HDSL frame
6
6
6
6
—
5
5
5
5
0 = Negative sign bit
1 = Positive sign bit
0 = Negative sign bit
1 = Positive sign bit
—
4
4
4
4
Conexant
RFIFO_WL[7:0]
SYNC_WORD_A[6:0]
SYNC_WORD_B[6:0]
—
3
3
3
3
—
2
2
2
2
4.7 HDSL Channel Configuration
—
1
1
1
1
HFRAME_LEN[8]
4.0 Registers
0
0
0
0
4-31