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

46-1500

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 transparency-processing 7d, 5e is converted to 7e and 7d, 5d is converted to 7d.

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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Maxim DS33Z41 specifications 15. X.86 Encapsulation of the MAC field