Maxim Integrated DS33R11 - Manual (Page 179)

DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver
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Register Name: SU.TFRC
Register Description: Transmit Frame Resend Control
Register Address: 151h
Bit
# 7 6 5 4 3 2 1 0
Name - - - - NCFQ TPDFCB TPRHBC TPRCB
Default 0 0 0 0 0 0 0 0
Bit 3: No Carrier Queue Flush Bar (NCFQ) If this bit is set to 1, the queue for data passing from Serial Interface
to Ethernet Interface will not be flushed when loss of carrier is detected.
Bit 2: Transmit Packet Deferred Fail Control Enable (TPDFCB) If this bit if set to 1, the current frame is
transmitted immediately instead of being deferred. If this bit is set to 0, the frame is deferred if CRS is asserted and
sent when the CRS is unasserted indicating the media is idle.
Bit 1: Transmit Packet HB Fail Control Bar (TPRHBC) If this bit is set to 1, the current frame will not be
retransmitted if a heartbeat failure is detected.
Bit 0: Transmit Packet Resend Control Bar (TPRCB) If this bit is set to 1, the current frame will not be
retransmitted if any of the following errors have occurred:
• Jabber time out
• Loss of carrier
• Excessive deferral
• Late collision
• Excessive collisions
• Under run
• Collision
Note that blocking retransmission due to collision (applicable in MIII/Half Duplex Mode) can result in unpredictable
system level behavior.