RS8953 Conexant Systems, Inc., RS8953 Datasheet - Page 110

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

4.0 Registers
4.10 Data Path Options
INSERT_EN
MPU access to the Receive Combination Table’s (COMBINE_TBL) single register is enabled by writing
COMB_EN [CMD_3; addr 0xE7], and by writing a maximum of 64 table entries sequentially to
COMBINE_TBL. Each write increments the table pointer, and the first write corresponds to the first receive
PCM timeslot. Subsequent writes increment the table pointer to successive timeslots. After writing the required
number of table entries (see ROUTE_TBL), the MPU writes COMB_EN to disable table access, and then writes
RFIFO_RST [addr 0x62] on every HDSL channel to realign the receive elastic stores. The MPU possibly writes
RX_RST [addr 0xF1] if the aggregate PCM data rate has been modified. Subsequent table changes can rewrite
entries only up to and including the last desired modification.
COMBINE[1:0]
BER_EN
DROP_EN
4-42
0xEE—Receive Combination Table (COMBINE_TBL)
—
7
Enable INSERT—Controls the state of the internal MUX and the INSERT output pin during
the corresponding PCM timeslot’s sample time. The next table entry is programmed to select
the previous timeslot (ROUTE = 11) and to place INSDAT data from the previous timeslot into
the TFIFO.
Combine Code—Selects one of four data sources for output on RSER during the respective
receive PCM timeslot destination. The data source is selected from one of three HDSL receive
channels or the DBANK register. The first combine code that selects data from a HDSL
channel will receive the first payload byte mapped from that channel’s payload block, as
determined by the payload map [RMAP; addr 0x64]. Whenever combine [1:0] is not 00,
DBANK_SEL[1:0] must be 00.
BER Meter Enable—Places a copy of the respective PCM timeslot’s data into the BER meter.
Any number of timeslots may be copied without affecting throughput.
Enable DROP—Controls the state of the DROP output pin which marks the respective timeslot
coincident with data output on RSER.
—
6
COMBINE[1:0]
5
0 = INSERT output pin remains inactive (low)
1 = INSERT output pin active (high)
0 = BER Meter ignores PCM timeslot
1 = BER Meter receives copy of PCM timeslot data from RSER
0 = DROP output pin remains inactive (low)
1 = DROP output pin active (high)
DBANK_SEL
00
01
10
11
4
Conexant
DROP_EN
Determined by DBANK_SEL[1:0]
3
HDSL receive channel 1
HDSL receive channel 2
HDSL receive channel 3
Source of RSER Data
BER_EN
2
RS8953B/8953SPB
1
HDSL Channel Unit
COMBINE[1:0]
N8953BDSB
0