LAN91C100 Datasheet, PDF (7/101 Pages) SMSC Corporation – FEAST™ Fast Ethernet Controller

DESCRIPTION OF PIN FUNCTIONSOF PIN FUNCTIONSPIN FUNCTIONS
PQFP/TQFP
PIN NO.
NAME
42,
RAM Data
40-38, Bus
36-33, 59,56,
49-47,
45-43,
69-67, 65,64,
62-60,
81-76, 71,70
SYMBOL
RD0-RD31
BUFFER
TYPE
I/O4P
DESCRIPTION
Bidirectional. Carries the local buffer
memory read and write data. Reads are
always 32 bits wide. Writes are controlled
individually at the byte level.
84,87,
88,90,
91,96,
99,101,
100,98,
89,92,
103,102,
104
RAM
Address
Bus
RA2-RA16
O4 Outputs. This bus specifies the buffer RAM
doubleword being accessed by the
LAN91C100.
97
nROE
O4 Output. Used to read a doubleword from
buffer RAM.
31,57,
73,86
nRWE0-
RWE3
O4 Outputs. Used to write any byte, word or
dword in RAM.
93
nReceive nRCVDMA
O4 Output. This pin is active during
DMA
LAN91C100 write memory cycles of receive
packets.
3
Crystal 1 XTAL1
4
Crystal 2 XTAL2
ICLK An external 25 MHz crystal is connected
across these pins. If a TTL clock is supplied
instead, it should be connected to XTAL1
and XTAL2 should be left open.
5,10,
23,27,
41,63,
74,83,
85,107,
119,125,
132,143,
165,179,
186,191
Power
VDD
+5V power supply pins.
205
Analog
Power
AVDD
+5V analog power supply pin.
7