RS8953 Conexant Systems, Inc., RS8953 Datasheet - Page 58

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

3.0 Circuit Descriptions
3.5 HDSL Channel
3-26
3.5.1.6 2B1Q Encoder
transmit STUFF bits by setting SLV_STUF [TCMD_2; addr 0x07] and selecting
the alternate source in STUFF_SEL [CMD_5; addr 0xE9]. Alternate STUFF bits
can be supplied by other HDSL channels, or the MPU can directly manipulate
EXT_STUFF [CMD_5; addr 0xE9]. For systems that externally synchronize
PCM and HDSL clock phase, the STUFF generator can also be programmed to
insert an alternating pattern of 0 and 4 STUFF bits.
The 2B1Q (2 Binary, 1 Quaternary) encoder provides the ability to directly
interface to the Conexant HDSL transceiver. The 2B1Q encoder converts HDSL
data generated internally at the bit rate into sign and magnitude data according to
the quaternary alignment provided on the QCLKn input. (Refer to
sign and magnitude bits used to generate 2B1Q coded outputs on TDATn.)
Table 3-4. 2B1Q Encoder Alignment
Table 3-5. Z-Bit Definitions
8 to 46
The MPU can bypass the STUFF generator and select an alternate source of
Z-bit
(Zn)
47
48
1
2
3
4
5
6
7
First Bit
(Sign)
1
1
0
0
Loop1
1
0
0
x
x
x
x
x
x
x
Conexant
Loop2
0
1
0
x
x
x
x
x
x
x
(Magnitudes)
Second Bit
0
1
1
0
Loop3
0
0
1
x
x
x
x
x
x
x
Pair Identification
Pair Identification
Pair Identification
Quaternary Symbol
RS8953B/8953SPB
Comments
Not defined
Not defined
Not defined
Not defined
Not defined
Not defined
Not defined
HDSL Channel Unit
(Quat)
–1
+3
+1
–3
Table 3-4
N8953BDSB
for