XRT79L71_1 Datasheet, PDF (51/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

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XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
BIT NUMBER
NAME
1-0
Cell Size[1:0]
TYPE
DESCRIPTION
Cell Size[1:0]:
These two READ/WRITE bit-fields permit the user to specify the
size of the ATM cell that will be handled by the Receive UTOPIA
Interface blocks. The relationship between the contents of these
bit-fields and the corresponding Cell Sizes are tabulated below.
Cell Size[1:0] Resulting Cell Size (Bytes)
0
0
52 bytes
53 bytes (Only valid for
0
1
UTOPIA Level 1, and if the
UTOPIA Data Bus W idth is set
to 8 bits)
54 bytes (Only valid for
1
0
UTOPIA Levels 1 and 2)
1
1
56 bytes
NOTE: The user must bear in mind the UTOPIA Level and the
UTOPIA Data Bus width selected, when selecting the
Cell Size.
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