RS8953 Conexant Systems, Inc., RS8953 Datasheet - Page 114

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

4.0 Registers
4.11 Common Command
COMB_EN
ROUTE_EN
PRBS_DIS
BER_SCALE[1:0]
PRBS_MODE[1:0]
RSIG_WR
4-46
0xE7—Command Register 3 (CMD_3)
RSIG_WR
7
Enable Receive Combination Table Access—The write pointer for the combination table
[COMBINE_TBL; addr 0xEE] is reset to 0, and table access is enabled. MPU writes to
COMBINE_TBL are ignored when COMB_EN is low.
Enable Transmit Routing Table Access—The write pointer for the transmit routing table
[ROUTE_TBL; addr 0xED] is reset to 0, and table access is enabled. MPU writes to
ROUTE_TBL are ignored when ROUTE_EN is low.
PRBS Disable—Replaces PRBS generator output with data from the Fill Pattern Register
[FILL_PATT; addr 0xEA]. Fill patterns are routed to the transmit FIFO in the same manner as
PRBS patterns.
BER Meter Scale—Selects the test interval over which bit errors are accumulated by the BER
Meter [BER_METER; addr 0x1D]. The test interval is counted only during bits selected and
checked by the BER meter. See also BER_SEL [CMD_6; addr 0xF3].
NOTE:
Pseudo-Random Bit Sequence Length—Establishes the LFSR pattern generated by the
transmit PRBS generator and checked by the receive BER meter. There is an inverter in the
data path when the 2
Enable Receive Signaling Table Access—The write pointer for the Receive Signaling Table
[RSIG_TBL; addr 0xF2] is reset to 0, and table access is enabled. MPU writes to RSIG_TBL
are ignored when RSIG_WR is low.
6
PRBS_MODE[1:0]
The time to complete the test interval depends on the number of bytes examined in
each frame, where total test time may exceed 9 hours and 19 minutes.
PRBS_MODE
5
BER_SCALE
0 = Disable access to COMBINE_TBL
1 = Enable MPU access to COMBINE_TBL and reset write pointer
0 = Disable access to ROUTE_TBL
1 = Enable MPU access to ROUTE_TBL and reset write pointer
0 = PRBS generator output enabled
1 = Fill Pattern replaces PRBS data
0 = Disable access to RSIG_TBL
1 = Enable MPU access to RSIG_TBL and reset write pointer
15
00
01
10
11
00
01
10
11
test pattern is selected.
4
BER_SCALE[1:0]
Conexant
2
Test Interval
20
Test Pattern
2
2
2
2
(14-zero limit)
31
28
25
21
3
bits
bits
bits
bits
2
2
2
23
15
4
PRBS_DIS
2
Approximate Scale
LFSR Tap Selection
2 x 10
2 x 10
3 x 10
2 x 10
ROUTE_EN
1 + x
1 + x
1 + x
1 + x
RS8953B/8953SPB
1
18
17
14
9
8
7
6
HDSL Channel Unit
3
+ x
+ x
+ x
+ x
23
20
15
4
N8953BDSB
COMB_EN
0