pin description for 64/68 pin packages, Pin description for 64/68 pin packages – Rainbow Electronics T89C51RD2 User Manual
Page 9
Rev. F - 15 February, 2001
9
T89C51RD2
5.1. Pin Description for 64/68 pin Packages
Port 4 and Port 5 are 8-bit bidirectional I/O ports with internal pull-ups. Pins that have 1 written to them are pulled
high by the internal pull ups and can be used as inputs.
As inputs, pins that are externally pulled low will source current because of the internal pull-ups.
Refer to the previous pin description for other pins.
PLCC68
SQUARE
VQFP64 1.4
VSS
51, 18
9/40
VCC
17
8
P0.0
15
6
P0.1
14
5
P0.2
12
3
P0.3
11
2
P0.4
9
64
P0.5
6
61
P0.6
5
60
P0.7
3
59
P1.0
19
10
P1.1
21
12
P1.2
22
13
P1.3
23
14
P1.4
25
16
P1.5
27
18
P1.6
28
19
P1.7
29
20
P2.0
54
43
P2.1
55
44
P2.2
56
45
P2.3
58
47
P2.4
59
48
P2.5
61
50
P2.6
64
53
P2.7
65
54
P3.0
34
25
P3.1
39
28
P3.2
40
29
P3.3
41
30
P3.4
42
31
P3.5
43
32
P3.6
45
34
P3.7
47
36
RESET
30
21
ALE/PROG
68
56
PSEN
67
55
EA
2
58
XTAL1
49
38
XTAL2
48
37
P4.0
20
11
P4.1
24
15
P4.2
26
17
P4.3
44
33
P4.4
46
35
P4.5
50
39
P4.6
53
42
P4.7
57
46
P5.0
60
49
P5.1
62
51
P5.2
63
52
P5.3
7
62
P5.4
8
63
P5.5
10
1
P5.6
13
4
P5.7
16
7