5.0 Memory Organization
CN8478/CN8474A/CN8472A/CN8471A
5.2 Descriptors
Multichannel Synchronous Communications Controller (MUSYCC™)
Table 5-25. Receive Buffer Status Descriptor
Bit
Field
Name
Value
Description
31
OWNER
0
MUSYCC Owns Buffer. Until MUSYCC relinquishes control, the data in this descriptor
is being used by MUSYCC.
1
Host Owns Buffer. MUSYCC has relinquished control of buffer back to host. MUSYCC
is done processing buffer.
30
29
RSVD
EOM
0
0
1
Reserved.
End of Message Indicator. The last octet for this message is not in this buffer.
End of Message indicator. The last octet for this data message is in this buffer either
because a valid closing flag (7Eh) was detected or the receiver terminated due to an
error condition.
28:20
19:16
RSVD
0
0
1
2
Reserved.
ERROR[3:0]
OK: No error detected in this receive buffer.
BUFF: Buffer Error. Data is lost. For receive: Internal data buffer overflow.
COFA: Change Of Frame Alignment. RSYNC signal is misaligned with the flywheel in
the serial interface.
3–7
8
Reserved.
OOF: Out of Frame. ROOF signal is asserted.
9
FCS: Frame Check Sequence Error. Received HDLC frame is terminated with proper
7Eh flag, but computed FCS does not match received FCS.
10
11
12
ALIGN: Octet Alignment Error. Message payload size, after zero extraction, is not a
multiple of 8 bits. This error takes precedence over an FCS error.
ABT: Abort Flag Termination. Received message is terminated with abort sequence,
seven sequential 1s, instead of a closing flag (7Eh).
LNG: Long Message. Message payload size greater than selected limit was received.
Message processing is terminated and transfer to shared memory is discontinued.
Channel resumes scanning for HDLC flags or idle codes.
13–15
0
Reserved.
15:14
13:0
RSVD
Reserved.
DLEN[13:0]
—
Received Octets.
5-36
Conexant
100660E
CONEXANT [ CONEXANT SYSTEMS, INC ]
