
DS33Z41 Quad IMUX Ethernet Mapper
Figure 8-15. X.86 Encapsulation of the MAC field
Flag(0x7E)
Address(0x04)
Control(0x03)
1st Octect of SAPI(0xfe)
2nd Octect of SAPI(0x01)
Destination Adrs(DA)
Source Adrs(SA)
Length/Type
MAC Client Data
PAD
FCS for MAC
FCS for LAPS
Flag(0x7E)
Number of Bytes 1 1 1 1 1 6 6 2
4
4
MSB
LSB
The DS33Z41 will encode the MAC Frame with the LAPS encapsulation on a complete serial stream if configured for X.86 mode in the register LI.TX86E. The DS33Z41 provides the following functions:
•Control Registers for Address, SAPI, Destination Address, Source Address.
•32 bit FCS enabled.
•Programmable X43+1 scrambling.
The sequence of processing performed by the receiver is as follows:
•Programmable octets X43+1 descrambling.
•Detect the Start Flag (7E).
•Remove Rate adaptation octets 7d, dd.
•Perform
•Check for a valid Address, Control and SAPI fields (LI.TRX86A to LI.TRX86SAPIL).
•Perform FCS checking.
•Detect the closing flag.
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