The Microcontroller Idea Book - Jan Axelson's Lakeview Research

Inside the 8052-BASIC
Table 2-2. (page 2 of 2)
Pin Symbol Input/
Output
21 P2.0
A8
22 P2.1
A9
23 P2.2
A10
24 P2.3
A11
25 P2.4
A12
26 P2.5
A13
27 P2.6
A14
28 P2.7
A15
8052
Function
I/O Port 2, bit 0
Address bit 8
I/O Port 2, bit 1
Address bit 9
I/O Port 2, bit 2
Address bit 10
I/O Port 2, bit 3
Address bit 11
I/O Port 2, bit 4
Address bit 12
I/O Port 2, bit 5
Address bit 13
I/O Port 2, bit 6
Address bit 14
I/O Port 2, bit 7
Address bit 15
29 PSEN Output Program store enable
Read strobe for external
program memory
30 ALE Output Address latch enable
8052-BASIC Additions
(none on pins 21-40)
31 EA Input External access enable for
program memory
32 P0.7
AD7
33 P0.6
AD6
34 P0.5
AD5
35 P0.4
AD4
36 P0.3
AD3
37 P0.2
AD2
38 P0.1
AD1
39 P0.0
AD0
I/O Port 0, bit 7
Address/data bit 7
I/O Port 0, bit 6
Address/data bit 6
I/O Port 0, bit 5
Address/data bit 5
I/O Port 0, bit 4
Address/data bit 4
I/O Port 0, bit 3
Address/data bit 3
I/O Port 0, bit 2
Address/data bit 2
I//O Port 0, bit 1
Address/data bit 1
I/O Port 0, bit 0
Address/data bit 0
40 Vcc Input Supply voltage
The Microcontroller Idea Book 19