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ADDR = 0x182: Transmit Control/Type_L Byte
Bit 7
Bit 6
Bit name TX_CNT_TYPE_L[7:0]
R/W
R/W
Value
0x03
after
reset
Bits 7-0: TX_CNT_TYPE_L[7:0] specifies the Control Byte for LAPS mode and the LSB of the TYPE field
for GFP mode, which is the Payload Identifier. This byte will be sent out in the encapsulated
LAPS/GFP frame from the Ethernet side to the SONET/SDH side if the TX_CNT_INH or the
TX_TYPE_INH bit is not set, respectively. The default value is assigned to 0x03 for LAPS since
LAPS is the default mode. For GFP mode, this register must be programmed to 0x01 for Ethernet.
ADDR = 0x183: Transmit Rate Adaptation/Type_H Byte
Bit 7
Bit 6
Bit name TX_RA_TYPE_H[7:0]
R/W
R/W
Value
0xDD
after
reset
Bits 7-0: TX_RA_TYPE_H[7:0] specifies the Rate Adaptation Byte for LAPS mode and the MSB of the
TYPE field for GFP mode, which consists of the Extension Header Identification, Payload FCS
Indicator and Payload Type Identifier. In LAPS mode, this byte is inserted into the TX Payload
Data sent from the Ethernet side to the SONET/SDH side if the TX_RA_INH bit is not set and
an underrun occurs in the TX FIFO. Rate Adaptation is used to accommodate the rate
difference between the faster SONET/SDH clock and the slower MII clock. In GFP mode, this byte
is inserted into the Type Header sent from the Ethernet side to the SONET/SDH side if the
TX_TYPE_INH bit is not set, and should be set to 0x10 for Null Headers with FCS.
80
Bit 5
Bit 4
Bit 5
Bit 4
Bit 3
Bit 2
Bit 3
Bit 2
Bit 1
Bit 0
Bit 1
Bit 0
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