LAN91C100FD_08 Datasheet, PDF (33/77 Pages) SMSC Corporation – FEAST Fast Ethernet Controller with Full Duplex Capability

FEAST Fast Ethernet Controller with Full Duplex Capability
Note:
ALLOCATED PACKET NUMBER - Packet number associated with the last memory allocation request.
The value is only valid if the FAILED bit is clear.
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).
BANK 2
OFFSET
4
NAME
FIFO PORTS REGISTER
TYPE
READ ONLY
SYMBOL
FIFO
This register provides access to the read ports of the Receive FIFO and the Transmit completion FIFO.
The packet numbers to be processed by the interrupt service routines are read from this register.
HIGH REMPTY
0
BYTE
RX FIFO PACKET NUMBER
1
0
0
0
0
0
0
0
LOW TEMPTY
0
BYTE
TX DONE PACKET NUMBER
1
0
0
0
0
0
0
0
Note:
REMPTY - No receive packets queued in the RX FIFO. For polling purposes, uses the RCV_INT bit in the
Interrupt Status Register.
TOP OF RX FIFO PACKET NUMBER - Packet number presently at the output of the RX FIFO. Only valid
if REMPTY is clear. The packet is removed from the RX FIFO using MMU Commands 3) or 4).
TEMPTY - No transmit packets in completion queue. For polling purposes, uses the TX_INT bit in the
Interrupt Status Register.
TX DONE PACKET NUMBER - Packet number presently at the output of the TX Completion FIFO. Only
valid if TEMPTY is clear. The packet is removed when a TX INT acknowledge is issued.
For software compatibility with future versions, the value read from each FIFO register is intended to be
written into the PNR as is, without masking higher bits (provided TEMPTY and REMPTY = 0 respectively).
BANK 2
OFFSET
6
HIGH
BYTE
LOW
BYTE
RCV
0
0
NAME
TYPE
SYMBOL
POINTER REGISTER
READ/WRITE
PTR
NOT EMPTY is a read
only bit
AUTO
INCR.
READ
Reserved NOT
EMPTY
POINTER HIGH
0
0
0
0
0
0
0
POINTER LOW
0
0
0
0
0
0
0
POINTER REGISTER - The value of this register determines the address to be accessed within the
transmit or receive areas. It will auto-increment on accesses to the data register when AUTO INCR. is set.
The increment is by one for every byte access, by two for every word access, and by four for every double
word access. When RCV is set the address refers to the receive area and uses the output of RX FIFO as
the packet number, when RCV is clear the address refers to the transmit area and uses the packet number
at the Packet Number Register.
SMSC LAN91C100FD Rev. D
Page 33
DATASHEET
Revision 1.0 (09-22-08)