PM4341AT1XC
DATA SHEET
PMC-900602
ISSUE 7
T1 FRAMER/TRANSCEIVER
Register 34H: XFDL Configuration
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Unused
Unused
Unused
EOM
X
X
X
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
INTE
ABT
CRC
EN
EN:
The enable bit (EN) controls the overall operation of the XFDL. When the EN
bit is set to a logic 1, the XDFL is enabled and flag sequences are sent until
data is written into the Transmit Data register. When the EN bit is set to logic
0, the XFDL is disabled.
CRC:
The CRC enable bit controls the generation of the CCITT-CRC frame check
sequence (FCS). Setting the CRC bit to logic 1 enables the CCITT-CRC
generator and the appends the 16 bit FCS to the end of each message.
When the CRC bit is set to logic 0, the FCS is not appended to the end of the
message. The CRC type used is the CCITT-CRC with generator polynomial =
16
12
5
x
+ x +x + 1.The high order bit of the FCS word is transmitted first.
ABT:
The Abort (ABT) bit controls the sending of the 7 consecutive ones HDLC
abort code. Setting the ABT bit to a logic 1 causes the 11111110 code to be
transmitted after the last byte from the Transmit Data Register is transmitted.
Aborts are continuously sent until this bit is reset to a logic 0.
INTE:
The INTE bit enables the generation of an interrupt via the TDLINT output.
Setting the INTE bit to logic 1 enables the generation of an interrupt; setting
INTE to logic 0 disables the generation of an interrupt. If the TDLINTE bit is
also set to logic 1 in the Datalink Options register, the interrupt generated on
the TDLINT output is also generated on the microprocessor INTB pin.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
137
PMC [ PMC-SIERRA, INC ]
