The Microcontroller Idea Book - Jan Axelson's Lakeview Research

Inputs and Outputs
Pin Symbol Input/
Output
Function
21 PB3 I/O Port B, bit 3
22 PB4 I/O Port B, bit 4
23 PB5 I/O Port B, bit 5
24 PB6 I/O Port B, bit 6
25 PB7 I/O Port B, bit 7
26 Vcc I Power supply (+5V)
27 D7 I/O Data bit 7
28 D6 I/O Data bit 6
29 D5 I/O Data bit 5
30 D4 I/O Data bit 4
31 D3 I/O Data bit 3
32 D2 I/O Data bit 2
33 D1 I/O Data bit 1
34 D0 I/O Data bit 0
35 RESET I Reset ports to input; clear control register
36 WR I Write
37 PA7 I/O Port A, bit 7
38 PA6 I/O Port A, bit 6
39 PA5 I/O Port A, bit 5
40 PA4 I/O Port A, bit 4
The Microcontroller Idea Book 101