cx28250 Mindspeed Technologies, cx28250 Datasheet - Page 70

• Manufacturer Part Number: cx28250
• Description: Cx28250 Atm Physical Interface Phy Devices
• Manufacturer: Mindspeed Technologies

2.0 Functional Description
2.4 ATM Cell Processor
2.4.3 Cell Payload Scrambler
2-34
The ATM standard requires cell payload scrambling in order to ensure that only
valid headers are found in the cell delineation process. Scrambling randomizes
any repeated patterns or other data strings that could be mistaken for valid
headers.
leaving the 5 header bytes untouched. Payload scrambling is enabled by setting bit
5 in register CGEN (0x04).
The descrambler polynomial is self-synchronizing. It can be enabled by writing
bit 5 in register CVAL (0x08) to 1.
Payload scrambling uses the polynomial x
Descrambling uses the same polynomial to recover the 48-byte cell payload.
Mindspeed Technologies
™
ATM Physical Interface (PHY) Devices
43
+1 to scramble the payload,
28250-DSH-002-C
CX28250