D7
D6
D5
D4
D3
D2
D1
D0
P0.0
P0.1
P0.2
D0
D1
D2
D3
D4
D5
D6
D7
B
OE
ST
ST A
EOC C
A
B
C
ST
EOC
CLK
OE
CLK
P0.0
P0.1
P0.2
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7
XTAL2
18
XTAL1
19
ALE
30
EA
31
PSEN
29
RST
9
P0.0/AD0
39
P0.1/AD1
38
P0.2/AD2
37
P0.3/AD3
36
P0.4/AD4
35
P0.5/AD5
34
P0.6/AD6
33
P0.7/AD7
32
P1.0
1
P1.1
2
P1.2
3
P1.3
4
P1.4
5
P1.5
6
P1.6
7
P1.7
8
P3.0/RXD
10
P3.1/TXD
11
P3.2/INT0
12
P3.3/INT1
13
P3.4/T0
14
P3.7/RD
17
P3.6/WR
16
P3.5/T1
15
P2.7/A15
28
P2.0/A8
21
P2.1/A9
22
P2.2/A10
23
P2.3/A11
24
P2.4/A12
25
P2.5/A13
26
P2.6/A14
27
U1
AT89C51
OUT1
21
ADD B
24
ADD A
25
ADD C
23
VREF(+)
12
VREF(-)
16
IN3
1
IN4
2
IN5
3
IN6
4
IN7
5
START
6
OUT5
8
EOC
7
OE
9
CLOCK
10
OUT2
20
OUT7
14
OUT6
15
OUT8
17
OUT4
18
OUT3
19
IN2
28
IN1
27
IN0
26
ALE
22
U3
ADC0809
46%
RV1
10k
C1
22pF
C2
22pF
C3
10uF
X1
12M
R1
10k
2
3
4
5
6
7
8
9
1
RP1
+88.8
Volts
D7
14
D6
13
D5
12
D4
11
D3
10
D2
9
D1
8
D0
7
E
6
RW
5
RS
4
VSS
1
VDD
2
VEE
3
LCD1
LM016L
48%
RV2
10k