78P2351 Single Channel OC-3/STM1-E/E4 Line Interface Unit
REGISTER DESCRIPTION (continued)
PORT-SPECIFIC REGISTERS
For PA[3:0] = 1 only. Accessing a register with port address greater than 1 constitutes an invalid command, and
the read/write operation will be ignored.
ADDRESS 1-0: MODE CONTROL REGISTER
DFLT
BIT
NAME
TYPE
DESCRIPTION
VALUE
Transmitter Power-Down:
0 : Normal Operation
7
PDTX
R/W
0
1 : Power-Down. CMI Transmit outputs are also tri-stated.
Receiver Power-Down:
6
PDRX
R/W
0
0 : Normal Operation
1 : Power-Down
Parallel Mode Interface Selection:
When PAR=1, (Master Control Regsiter: bit 5), PMODE selects the
source of the transmit parallel clock, either taken from the framer
externally or generated internally. Default value is determined by
CKMODE pin setting upon power up or reset.
5
PMODE
R/W
X
0: Slave Timing. PICK clock input to the transmitter
1: Master Timing. PTOCK clock output from the transmitter
When PAR=0, PMODE is invalid and defaults to logic ‘1’
Serial Mode Interface Selection:
When PAR=0 (Master Control Regsiter: bit 5), SMOD[1:0] configures
the transmitter’s system interface. Default values determined by
CKMODE pin setting upon power up or reset.
SMOD[1] SMOD[0]
4
SMOD[1]
R/W
X
0
1
0
0
0
1
Synchronous clock and data are passed through a
FIFO. The CDR is bypassed.
Synchronous data is passed through the CDR and
then through the FIFO.
Plesiochronous data is passed through the CDR to
recover a clock. FIFO is bypassed because the
data is not synchronous with the reference clock.
Loop Timing Mode Enable: The recovered receive
clock is used as the reference for the transmitter.
The transmit data is passed through the CDR, but
the FIFO is bypassed.
1
1
3
SMOD[0]
R/W
X
When PAR=1, setting SMOD[1:0] = 11 will enabled Loop Timing Mode.
Default values are determined by CKMODE pin setting upon power up
or reset as follows:
CKMODE Low ꢀSMOD[1:0] default = 00 (no effect)
CKMODE Float ꢀSMOD[1:0] default = 11 (loop-timing)
CKMODE High ꢀSMOD[1:0] default = 01 (no effect)
Receive Monitor Mode Enable:
0: Normal Operation
1: Adds 20dB of flat gain to the receive signal before equalization.
NOTE: Monitor mode is only available in CMI mode.
2
MON
--
R/W
R/W
0
1:0
00
Reserved
11
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
