SMC91C100 Datasheet, PDF (37/83 Pages) List of Unclassifed Manufacturers – FEAST Fast Ethernet Controller

I/O SPACE - BANK2
OFFSET
2
NAME
PACKET NUMBER REGISTER
TYPE
READ/WRITE
SYMBOL
PNR
PACKET NUMBER AT TX AREA
0
0
0
0
0
0
0
0
PACKET NUMBER AT TX AREA - The value
written into this register determines which packet
number is accessible through the TX area. Some
MMU commands use the number
stored in this register as the packet number
parameter. This register is cleared by a RESET or
a RESET MMU Command.
OFFSET
NAME
TYPE
3
ALLOCATION RESULT REGISTER
READ ONLY
This register is updated upon an ALLOCATE MEMORY MMU command.
SYMBOL
ARR
FAILED
ALLOCATED PACKET NUMBER
1
0
0
0
0
0
0
0
FAILED A zero indicates a successful allocation
completion. If the allocation fails the bit is set and
only cleared when the pending allocation is
satisfied. Defaults high upon reset and reset
MMU command. For polling purposes, the
ALLOC_INT in the Interrupt Status Register
should be used because it is synchronized to the
read operation. Sequence:
1) Allocate Command
2) Poll ALLOC_INT bit until set
3) Read Allocation Result Register
ALLOCATED PACKET NUMBER Packet
number associated with the last memory allocation
request. The value is only valid if the FAILED bit is
clear.
Note: For software compatibility with future
versions, the value read from the ARR after an
allocation request is intended to be written into the
PNR as is, without masking higher bits (provided
FAILED = 0).
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