Bt8370/8375/8376
1.0 Pin Descriptions
1.1 Pin Assignments
Fully Integrated T1/E1 Framer and Line Interface
Table 1-1. Hardware Signal Definitions (6 of 8)
Pin Label
Signal Name
I/O
Definition
Receive System Bus (RSB)
RSBCKI
RSB Clock Input
I
Bit clock and I/O signal timing for RSB according to system bus mode (see
[SBI_CR; addr 0D0]). System chooses from 1 of four different clocks to
act as RSB clock source (see [CMUX; addr 01A]). Rising or falling edge
clocks are independently configurable for data signals RPCMO, RSIGO,
RINDO and sync signals RFSYNC, RMSYNC (see [RPCM_NEG and
RSYN_NEG; addr 0D1]). When configured to operate at twice the data
rate, RSB clock is internally divided by 2 before clocking RSB data signals.
RPCMO
RSB Data Output
O
Serial data formatted into RSB frames consisting of DS0 channel time
slots, optional F-bits, and optional ABCD signaling. Time slots are routed
through receive slip buffer (see [RSLIPn; addr 1C0–1FF]) according to
RSLIP mode (see [RSBI; addr 0D1]). Data for each output time slot is
assigned sequentially from received time slot data according to system
bus channel programming (see [ASSIGN; addr 0E0–0FF]). F-bits are
output at the start of each RSB frame or at the embedded time slot
location (see [EMBED; addr 0D0]). ABCD signaling is optionally inserted
on a per-channel basis (see [INSERT; addr 0E0–0FF]) from the local
signaling buffer (see [RLOCAL; addr 180–19F]) or from the receive
signaling buffer [RSIGn; addr 1A0–1BF]. When enabled, robbed bit
signaling or CAS reinsertion is performed according to T1/E1 mode: the
eighth time slot bit of every sixth T1 frame is replaced, or the 4-bit
signaling value in the E1 time slot 16 is replaced.
RSIGO
RSB Signaling Output
O
Serial data formatted into RSB frames consisting of ABCD signaling bits
for each system bus time slot. Four bits of RSIGO time slot carry signaling
state for each accompanying RPCMO time slot. Local or through signaling
bits are output in every frame for each time slot and updated once per RSB
multiframe, regardless of per-channel RPCMO signaling reinsertion.
RINDO
RSB Time Slot
Indicator
O
Active-high output pulse marks selective receive system bus time slots as
programmed by SBCn [addr 0E0–0FF]. RINDO occurs on RSBCKI rising or
falling edges as selected by RPCM_NEG (see [RSBI; addr 0D1]).
RFSYNC
RSB Frame Sync
PIO
Input or output RSB frame sync (see [RFSYNC_IO; addr 018]). RFSYNC
output is active-high for 1 RSB clock cycle at programmed offset bit
location (see [RSYNC_BIT; addr 0D2]), marking offset bit within each RSB
frame and repeating once every 125 µs. RSB timebase and RFSYNC
output frame alignment begins at an arbitrary position and changes
alignment according to RSLIP mode (see [RSBI; addr 0D1]). When
RFSYNC is programmed as an input, the low-to-high signal transition is
detected and aligns RSB timebase to the programmed offset. RSB
timebase flywheels at 125 µs frame interval after the last RFSYNC is
applied.
RMSYNC
RSB Multiframe Sync
PIO
Input or output RSB multiframe sync (see [RMSYNC_IO; addr 018]).
RMSYNC output is active-high for 1 RSB clock cycle at programmed offset
bit location (see [RSYNC_BIT; addr 0D2]), marking offset bit within each
RSB multiframe and repeating once every 6 ms coinciding with RFSYNC.
RSB timebase and RMSYNC output multiframe alignment begins at an
arbitrary position and changes alignment according to RSLIP mode (see
[RSBI; addr 0D1]). When RMSYNC is programmed as input, the
low-to-high signal transition is detected and aligns the RSB timebase to
the programmed offset and the first frame of the multiframe. RSB
timebase flywheels at 6 ms multiframe interval after the last RMSYNC is
applied.
N8370DSE
Conexant
1-9
CONEXANT [ CONEXANT SYSTEMS, INC ]
