LAN91C100-FD-SS SMSC [SMSC Corporation], LAN91C100-FD-SS Datasheet - Page 36

• Manufacturer Part Number: LAN91C100-FD-SS
• Description: FEAST Fast Ethernet Controller with Full Duplex Capability
• Manufacturer: SMSC [SMSC Corporation]

nRXDISC PIN COUNTER - 8-bit counter increments when a packet is discarded due to the nRXDISC pin being active.
This counter will be reset to 00 when read. A count of FF will set the RX_DISC INT. The count will wrap around to 00 after
FF.
RCV DISCRD - Set to discard a packet being received. Will discard packets only in the process of being received. When
set prior to the end of receive packet, bit 4 (RXOVRN) of the interrupt status register will be set to indicate that the packet
was discarded. Otherwise, the packet will be received normally and bit 0 set (RCVINT) in the interrupt status register. RCV
DISCRD is self clearing.
ERCV THRESHOLD - Threshold for ERCV interrupt. Specified in 64 byte multiples. Whenever the number of bytes written
in memory for the presently received packet exceeds the ERCV THRESHOLD, ERCV INT bit of the INTERRUPT STATUS
REGISTER is set.
BANK7
nCSOUT is driven low by the LAN91C100FD when a valid access to the EXTERNAL REGISTER range occurs.
SMSC DS – LAN91C100FD REV. B
0 THROUGH 7
AEN=0
A3=0
A4-15 matches I/O BASE
BANK SELECT = 7
BANK SELECT = 4,5,6
Otherwise
HIGH
BYTE
BYTE
OFFSET
LOW
CYCLE
EXTERNAL REGISTERS
Driven low. Transparently latched on
nADS rising edge.
High
High
NAME
EXTERNAL R/W REGISTER
EXTERNAL R/W REGISTER
nCSOUT
Page 36
TYPE
Ignored on writes.
Tri-stated on reads.
Ignore cycle.
Normal LAN91C100FD cycle.
LAN91C100FD DATA BUS
SYMBOL
Rev. 01-20-06