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STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
303
PBS[2:0]
Significance
001
The data byte read from the FIFO is the dummy byte that was
written into the FIFO when the first HDLC flag sequence
(01111110) was detected. This indicates that the data link became
active.
The data byte read from the FIFO is the dummy byte that was
written into the FIFO when the HDLC abort sequence (01111111)
was detected. This indicates that the data link became inactive.
Reserved
The data byte read from the FIFO is the last byte of a normally
terminated packet with no CRC error and the packet received had
an integer number of bytes.
The data byte read from the FIFO must be discard because there
was a non-integer number of bytes in the packet.
The data byte read from the FIFO is the last byte of a normally
terminated packet with a CRC error. The packet was received in
error.
The data byte read from the FIFO is the last byte of a normally
terminated packet with a CRC error and a non-integer number of
bytes. The packet was received in error.
010
011
100
101
110
111
PKIN:
The Packet In (PKIN) bit is logic 1 when the last byte of a non-aborted packet
is written into the FIFO. The PKIN bit is cleared to logic 0 after the Status
Register is read.
COLS:
The Change of Link Status (COLS) bit is set to logic 1 if the RDLC has
detected the HDLC flag sequence (01111110) or HDLC abort sequence
(01111111) in the data. This indicates that there has been a change in the
data link status. The COLS bit is cleared to logic 0 by reading this register or
by clearing the EN bit in the Configuration Register. For each change in link
status, a byte is written into the FIFO. If the COLS bit is found to be logic 1
then the FIFO must be read until empty. The status of the data link is
determined by the PBS bits associated with the data read from the FIFO.
OVR:
The overrun (OVR) bit is set to logic 1 when data is written over unread data
in the FIFO buffer. This bit is not reset to logic 0 until after the Status