
á
PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
75
bit-field indicates that the “LAPD Message Reception
Complete” interrupt has occurred since the last read
of this register.
For more information on the LAPD Receiver, please
see Section 7.1.2.6.
3.3.2.21
Rx DS3 LAPD Status Register
Bit 6—RxAbort (Receive Abort Sequence)
This “Read-Only” bit-field indicates whether or not
the LAPD Receiver has detected the occurrence of
an “Abort Sequence” (e.g., a string of seven or more
consecutive “1s”) from the “far-end” LAPD Transmitter.
A “0” in this bit-field indicates that no “Abort-Sequence”
has been detected. A “1” in this bit-field indicates that
the “Abort-Sequence” has been detected.
For more information on the LAPD Receiver, please
see Section 7.1.2.6.
Bits, 5 and 4—RxLAPDType[1, 0]
These two “Read Only” bit-fields combine to indicate
the “type” of LAPD Message frame that has been
received by the LAPD Receiver. The relationship
between these two bit-fields and the LAPD Message
Type follows:
Bit 3—RxCR (Command/Response) Type
This “Read Only” bit field indicates the value of the C/R
(Command/Response) bit-field of the latest received
LAPD Message.
Bit 2—Rx FCS (Frame Check Sequence) Error
This “Read-Only” bit-field indicates whether or not
the LAPD Receiver has detected a “Frame Check
Sequence” (FCS) error in the newly received LAPD
Message Frame. A “0” in this bit-field indicates that
the FCS for the latest received LAPD Message
Frame is correct. A “1” in this bit-field indicates that
the FCS for the latest received LAPD Message
Frame is incorrect.
For more information on the LAPD Receiver, please
see Section 7.1.2.6.
Bit 1—End Of Message
This “Read-Only” bit-field indicates whether or not
the LAPD Receiver has completed its reception of
the latest incoming LAPD Message frame. The local
μP can poll the progress of the LAPD Receiver by
periodically reading this bit-field.
A “0” in this bit-field indicates that the LAPD Receiver
is still receiving the latest message from the “far end”
LAPD Transmitter. A “1” in this bit-field indicates that the
LAPD Receiver has finished receiving the complete
LAPD Message Frame.
Bit 0—Flag Present
This “Read-Only” bit-field indicates whether or not
the LAPD Receiver has detected the occurrence of
the Flag Sequence byte (7Eh). A “0” in this bit-field
indicates that the LAPD Receiver does not detect the
occurrence of the Flag Sequence byte. A “1” in this
bit-field indicates that the LAPD Receiver does detect
the occurrence of the Flag Sequence byte.
For more information on the LAPD Receiver, please
see Section 7.1.2.6.
Address = 15h, Rx DS3 LAPD Status Register
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Unused
RxAbort
RxLAPD Type [1:0]
RxCR Type
Rx FCS Error End-Of Message
Flag Present
RO
RO
RO
RO
RO
RO
RO
RO
0
1
0
0
0
0
0
0
B
IT
5
B
IT
4
M
ESSAGE
T
YPE
M
ESSAGE
L
ENGTH
0
0
Test Signal Identification
76 Bytes
0
1
Idle Signal Identification
76 Bytes
1
0
CL Path Identification
76 Bytes
1
1
ITU-T Path Identification
82 Bytes