cx29503 Mindspeed Technologies, cx29503 Datasheet - Page 207

• Manufacturer Part Number: cx29503
• Description: Cx29503 Broadband Access Multiplexer Data Sheet
• Manufacturer: Mindspeed Technologies

CX29503 Data Sheet
EOM[1, 0]
RDL1_CNT[5:0]
RDL1[7:0]
29503-DSH-002-B
RDL1[7]
EOM[1]
7
7
End Of Message (EOM)—Receive data link reports an EOM status for each occurrence of a
complete (Good), a continued (Partial), an errored (FCS/Non-integer), or an aborted (Abort)
message.
If an abort or error status with a 0 byte count is reported after the processor has already
buffered a prior HDLC Partial message, that partial buffered processor data should be
discarded. Abort status is reported if the receiver detects a string of 7 or more consecutive 1s
during an HDLC message. FCS error status is reported if the FCS mode is enabled, and the
checksum calculated over the received HDLC message does not match the received 16-bit
FCS. Non-integer error status is reported if the receiver detects a closing Flag character that
yields an HDLC message length which is not an integer number of 8-bit octets.
Byte Count [5:0]—Indicates the number of Message Data [WORD1] bytes that are stored in
subsequent consecutive FIFO locations, constituting one received message. The reported byte
count is the actual number of bytes, in the range of 0–63 bytes, where 0 indicates 0 bytes for
the processor to read. The processor can either read the specified number of message data
bytes consecutively from RDL1 or can poll RDL1_STAT after reading each data byte until
RDL1_STAT reports an EOM (i.e., RMPTY1 = 1 or RSTAT1 = 1).
Receive Message Data—Filled by the receiver data link, from LSB to MSB, with bits from the
selected channel. The processor reads 8-bit FIFO data during HDLC and Pack8 modes. During
Pack6 mode, only the 6 LSBs RDL1[5:0] are filled.
RDL1[6]
EOM[0]
6
6
WORD0: Message Status
00 = Good
01 = FCS/Non-integer
10 = Abort
11 = Partial
WORD1: Message Data
NOTE:
NOTE:
RDL1_CNT[5] RDL1_CNT[4] RDL1_CNT[3] RDL1_CNT[2] RDL1_CNT[1] RDL1_CNT[0]
RDL1[5]
5
5
Mindspeed Technologies™
Properly received unformatted messages are reported with a Partial EOM status. The
processor responds to Good or Partial status by reading the indicated number of data
bytes [RDL1_CNT] from RDL1. For abort or error cases, RDL1_CNT = 0 to indicate
that all received data from that message was discarded.
A Good status with RDL1_CNT = 0 is reported if the processor reads RDL1 while the
receiver is in progress of filling the FIFO (in which case RDL1_STAT contains RSTAT1
= 1 and RMSG1 = 1).
RDL1[4]
Preliminary Information
4
4
RDL1[3]
3
3
RDL1[2]
2
2
RDL1[1]
1
1
Register Description
RDL1[0]
0
0
8
-
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