T89C51RD2-RLUI-L View Datasheet(PDF) - Atmel Corporation
Part Name
Description
Manufacturer
T89C51RD2-RLUI-L Datasheet PDF : 86 Pages
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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.
VSS
VCC
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
RESET
ALE/PROG
PSEN
EA
XTAL1
XTAL2
P4.0
P4.1
P4.2
P4.3
P4.4
P4.5
P4.6
P4.7
P5.0
P5.1
P5.2
P5.3
P5.4
P5.5
P5.6
P5.7
PLCC68
51, 18
17
15
14
12
11
9
6
5
3
19
21
22
23
25
27
28
29
54
55
56
58
59
61
64
65
34
39
40
41
42
43
45
47
30
68
67
2
49
48
20
24
26
44
46
50
53
57
60
62
63
7
8
10
13
16
SQUARE
VQFP64 1.4
9/40
8
6
5
3
2
64
61
60
59
10
12
13
14
16
18
19
20
43
44
45
47
48
50
53
54
25
28
29
30
31
32
34
36
21
56
55
58
38
37
11
15
17
33
35
39
42
46
49
51
52
62
63
1
4
7
Rev. F - 15 February, 2001
9
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