DESCRIPTION OF PIN FUNCTIONSOF PIN FUNCTIONSPIN FUNCTIONS
PQFP/TQFP
PIN NO.
NAME
RAM Data
42,
Bus
40-38,
36-33, 59,56,
49-47,
45-43,
69-67, 65,64,
62-60,
81-76, 71,70
84,87,
88,90,
91,96,
99,101,
100,98,
89,92,
103,102,
104
97
31,57,
73,86
93
nReceive
DMA
Crystal 1
Crystal 2
RAM
Address
Bus
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.
RA2-RA16
O4
Outputs. This bus specifies the buffer RAM
doubleword being accessed by the
LAN91C100.
nROE
nRWE0-
RWE3
nRCVDMA
O4
O4
O4
Output. Used to read a doubleword from
buffer RAM.
Outputs. Used to write any byte, word or
dword in RAM.
Output.
This pin is active during
LAN91C100 write memory cycles of receive
packets.
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.
+5V power supply pins.
3
4
XTAL1
XTAL2
I
CLK
5,10,
23,27,
41,63,
74,83,
85,107,
119,125,
132,143,
165,179,
186,191
205
Power
VDD
Analog
Power
AVDD
+5V analog power supply pin.
7
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