SAE 81C90/91
07Feb95@09:05h Intermediate Version
Pin Definitions and Functions
Symbol
Pin Number
Input (I)
Function
Output (O)
PLCC-48 PLCC-28
1)
X1
11
28
O
I
Crystal oscillator output.
Must be unconnected for external clock input.
1)
X2
10
27
Crystal oscillator input.
Used for external clock input.
1)
CLKOUT
RES
14
19
42
43
44
1
3
O
Clock output
4
I
Reset. (Schmitt trigger characteristic)
PI: Address / Data bus / SI: Data input
PI: Address / Data bus / SI: Data output
PI: Address / Data bus / SI: Clock input
PI: Address / Data bus / SI: Write select
AD0/DI
AD1/DO
AD2/CLK
AD3/W
AD4/TIM
19
20
21
22
23
I/O
I/O
I/O
I/O
I/O
2
PI: Address / Data bus / SI:
TIM = 0: Timing A; TIM = 1: Timing B
AD5
AD6
AD7
RD
3
24
25
26
16
17
15
12
18
11
–
I/O
PI: Address/Data bus
PI: Address/Data bus
PI: Address/Data bus
PI: Read / SI: no Function
PI: Write / SI: no Function
PI: Address Latch Enable / SI:no Function
Chip Select
4
I/O
5
I/O
35
36
34
27
41
26
I
WR
ALE
CS
I
I
I
INT
MS
O
I
Interrupt
Mode Select (PI ↔ SI)
P00 … P03, 28, 29,
30, 31,
I/O
Port 0
These pins provide internal pullup resistors of
P04 … P07 37, 38,
39, 40
–
–
I/O
I/O
about 10...200 kΩ.
P10 … P13, 18, 17,
16, 15,
Port 1
These pins provide internal pullup resistors of
P14 … P17 9, 8, 7, 6 –
I/O
O
O
I
about 10...200 kΩ.
TX0
TX1
RX0
RX1
VDDA
25
24
23
22
20
10
9
Transmitter output 0
Transmitter output 1
2)
8
Comparator input 0 / Digital input
2)
7
I
Comparator input 1
5
I
Analog power supply for comparator
(may be unconnected using the digital mode)
Semiconductor Group
4
INFINEON [ Infineon ]
