Maxim Integrated DS33Z41 - Manual (Page 99)

DS33Z41 Quad IMUX Ethernet Mapper
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9.5.5 Receive Serial Interface
Serial Receive Registers are used to control the HDLC Receiver associated with each Serial Interface. Note that
throughout this document HDLC Processor is also referred to as “Packet Processor”. The receive packet
processor block has seventeen registers.
Register Name:
LI.RPPCL
Register Description: Receive Packet Processor Control Low Register
Register Address: 101h
Bit
# 7 6 5 4 3 2 1 0
Name — — RFPD RF16 RFED RDD RBRE RCCE
Default 0 0 0 0 0 0 0 0
Bit 5: Receive FCS Processing Disable (RFPD). When equal to 0, FCS processing is performed and FCS is
appended to packets. When set to 1, FCS processing is disabled (the packets do not have an FCS appended). In
X.86 mode, FCS processing is always enabled.
Bit 4: Receive FCS-16 Enable (RF16). When 0, the error checking circuit uses a 32-bit FCS. When 1, the error
checking circuit uses a 16-bit FCS. This bit is ignored when FCS processing is disabled. In X.86 mode, the FCS is
always 32 bits.
Bit 3: Receive FCS Extraction Disable (RFED). When 0, the FCS bytes are discarded. When 1, the FCS bytes
are passed on. This bit is ignored when FCS processing is disabled. In X.86 mode, FCS bytes are discarded.
Bit 2: Receive Descrambling Disable (RDD). When equal to 0, X 43 +1 descrambling is performed. When set to 1,
descrambling is disabled.
Bit 1: Receive Bit Reordering Enable (RBRE). When equal to 0, reordering is disabled and the first bit received
is expected to be the MSB DT [7] of the byte. When set to 1, bit reordering is enabled and the first bit received is
expected to be the LSB DT [0] of the byte. Note that function is controlled by the BREO in Hardware Mode.
Bit 0: Receive Clear Channel Enable (RCCE). When equal to 0, packet processing is enabled. When set to 1,
the device is in clear channel mode and all packet-processing functions except descrambling and bit reordering
are disabled.
Register Name:
LI.RMPSCL
Register Description: Receive Maximum Packet Size Control Low Register
Register Address: 102h
Bit
# 7 6 5 4 3 2 1 0
Name RMX7 RMX6 RMX5 RMX4 RMX3 RMX2 RMX1 RMX0
Default
1 1 1 0 0 0 0 0
Bits 7 to 0: Receive Maximum Packet Size (RMX7 to RMX0). Eight bits of a 16-bit value. Register description
below.