XRT79L71_1 Datasheet, PDF (249/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

REV. 1.0.0
XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
BIT NUMBER
NAME
7-0
Receive Cell Insertion/
Extraction Memory
Data[31:24]
TYPE
R/W
DESCRIPTION
Receive Cell Insertion/Extraction Memory Data[31:24]:
These READ/WRITE bit-fields, along with that in the Receive
ATM Cell Processor Block -Receive Cell Insertion/Extraction
Memory Data - Bytes 2 through 0 support the following functions.
a. They function as the address location, for which the user
to write the contents of an Outbound ATM cell into the
Receive Cell Insertion Memory, via the Microprocessor
Interface.
b. They function as the address location, for which the user
to read out the contents of an inbound ATM cell from the
Receive Cell Extraction Memory, via the Microprocessor
Interface.
NOTES:
1. If the user performs a WRITE operation to this (and the
other three address locations), then the user is writing
ATM cell data into the Receive Cell Insertion Memory.
2. If the user performs a READ operation to this (and the
other three address locations), then the user is reading
ATM cell data from the Receive Cell Extraction Memory.
3. READ and WRITE operations must be performed in a
32-bit (4-byte word) manner. Hence, whenever a user
performs a READ/WRITE operation to these address
locations, the user must start by writing in or reading
out the first byte (of this 4-byte word) of a given ATM
cell, into/from this particular address location. Next, the
user must perform the READ/WRITE operation (with
the second of this 4-byte word) to the Receive ATM Cell
Processor Block -Receive Cell Insertion/Extraction
Memory - Byte 2 register. Afterwards, the user must
perform a READ/WRITE operation (with the third of this
4-byte word) to the Receive ATM Cell Processor Block -
Receive Cell Insertion/Extraction Memory - Byte 1
register. Finally, the user must perform a READ/WRITE
operation (with the fourth of this 4-byte word) to the
Receive ATM Cell Processor Block - Receive Cell
Insertion/Extraction Memory - Byte 0 register. When
reading out (writing in) the next four bytes of a given
ATM cell, the user must repeat this process with a
READ or WRITE operation, from/to this register
location, and so on.
4. Whenever the user is writing cell data into the Receive
Cell Insertion Memory, the size of the Cell is always 56
bytes.
5. Whenever the user is reading cell data from the
Receive Cell Extraction Memory, the size of the Cell is
always 56 bytes.
240