XRT79L71_1 Datasheet, PDF (126/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
REV. 1.0.0
BIT NUMBER
NAME
5-4
RxLAPDType[1:0]
3
RxCR Type
2
RxFCS Error
1
End of Message
0
Flag Present
TYPE
R/O
DESCRIPTION
Receive LAPD Message Type Indicator [1:0]:
These two READ-ONLY bits indicate the type of LAPD Message
that is residing within the Receive LAPD Message buffer. The
relationship between the content of these two bit-fields and the
corresponding message type is presented below.
RxLAPDType[1:0]
0
0
0
1
1
0
1
1
Message Type
CL Path Identification
Idle Signal Identification
Test Signal Identification
ITU-T Path Identification
R/O Received C/R Value:
This READ-ONLY bit-field indicates the value of the C/R bit
(within one of the header bytes) of the most recently received
LAPD Message.
R/O Receive Frame Check Sequence (FCS) Error Indicator:
This READ-ONLY bit-field indicates whether or not the most
recently received LAPD Message frame contained an FCS error,
as described below.
0 - Indicates that the most recently received LAPD Message
frame does not contain an FCS error.
1 - Indicates that the most recently received LAPD Message
frame does contain an FCS error.
R/O End of Message Indicator:
This READ-ONLY bit-field indicates whether or not the Receive
LAPD Controller block has received a complete LAPD Message.
0 - Indicates that the Receive LAPD Controller block is still cur-
rently receiving a LAPD Message, but has not received the com-
plete message.
1 - Indicates that the Receive LAPD Controller block has
received a completed LAPD Message.
NOTE:
Once the Receive LAPD Controller block sets this bit-
field "High", this bit-field will remain high, until the
Receive LAPD Controller block begins to receive a new
LAPD Message.
R/O Receive Flag Sequence Indicator:
This READ-ONLY bit-field indicates whether or not the Receive
LAPD Controller block is currently receiving the Flag Sequence
(e.g., a continuous stream of 0x7E octets) within the Data Link
channel.
0 - Indicates that the Receive LAPD Controller block is NOT cur-
rently receiving the Flag Sequence octet.
1 - Indicates that the Receive LAPD Controller block is currently
receiving the Flag Sequence octet.
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