Owner manual

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