4-29
PQFP/TQFP
23
1
INDEX
CORNER
34
P1.0 VCCP1.1P1.2P1.4 P1.3 NC
42
43
40
41
6
5
4
44
3
2
26
25
28
27
24
18
19
20
21
22
P1.7
P1.6
P1.5
NC
7
8
9
10
11
12
13
14
15
16
17
29
30
39
38
37
36
35
33
32
31
NC
PSEN
XT
AL1
GND
XT
AL2
GND
P0.0
(AD0)
ALE/PROG
()
P
3
.
7
RD
EA/VPP
()
P
3
.
6
WR
(RXD) P3.0
P0.7 (AD7)
P2.6 (A14)
P0.6 (AD6)
P0.5 (AD5)
P0.4 (AD4)
P0.3
(AD3)
P0.2
(AD2)
P0.1
(AD1)
()P3.2INT0
(TXD) P3.1
(T1) P3.5
()P3.INT1
(T0) P3.4
P2.7 (A15)
(A11)
P2.3
(A12)
P2.4
(A10)
P2.2
(A
9)
P
2
.1
(A
8)
P
2
.0
RST
P2.5 (A13)
Features
• Compatible with MCS-51™ Products
• 4K Bytes of In-System Reprogrammable Flash Memory
– Endurance: 1,000 Write/Erase Cycles
• Fully Static Operation: 0 Hz to 24 MHz
• Three-Level Program Memory Lock
• 128 x 8-Bit Internal RAM
• 32 Programmable I/O Lines
• Two 16-Bit Timer/Counters
• Six Interrupt Sources
• Programmable Serial Channel
• Low Power Idle and Power Down Modes
Description
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K
bytes of Flash Programmable and Erasable Read Only Memory (PEROM). The
device is manufactured using Atmel’s high density nonvolatile memory technology
and is compatible with the industry standard MCS-51™ instruction set and pinout. The
on-chip Flash allows the program memory to be reprogrammed in-system or by a con-
ventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with
Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which
provides a highly flexible and cost effective solution to many embedded control appli-
cations.
PDIP
P1.0 VCC
P1.1 P0.0 (AD0)
P1.2
()P3.2INT0
ALE/PROG
()P3.7RD P2.3 (A11)
(TXD) P3.1
EA/VPP
()P3.6WR P2.4 (A12)
(RXD) P3.0
P0.7 (AD7)
(T1) P3.5
P2.6 (A14)
RST
P0.6 (AD6)P1.7
P0.5 (AD5)P1.6
P0.4 (AD4)P1.5
P0.3 (AD3)P1.4
P0.2 (AD2)P1.3
P0.1 (AD1)
().INT1
PSEN
XTAL2 P2.2 (A10)
(T0) P3.4
P2.7 (A15)
XTAL1 P2.1 (A9)
GND P2.0 (A8)
P2.5 (A13)
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
21
22
23
24
25
26
40
39
38
37
36
35
34
33
32
31
30
29
28
27
0265F-A–12/97
(continued)
8-Bit
Microcontroller
with 4K Bytes
Flash
AT89C51
Pin Configurations
PLCC
P1.0 VCCP1.1 P0.0
(AD0)
P1.2
ALE/PROG
()
P
3
.
7
RD
XT
AL1
EA/VPP
()
P
3
.
6
WR
GND
(RXD) P3.0
P0.7 (AD7)
P2.6 (A14)
P0.6 (AD6)
P0.5 (AD5)
P0.4 (AD4)
P0.3
(AD3)
P1.4 P0.2
(AD2)
P1.3 P0.1
(AD1)
PSEN
XT
AL2
()P3.2INT0
(TXD) P3.1
(T1) P3.5
()P3.INT1
(T0) P3.4
P2.7 (A15)
(A11)
P2.3
(A12)
P2.4
(A10)
P2.2
(A
9)
P
2
.1
(A
8)
P
2
.0
NC
23
1
RST
P1.7
P1.6
P1.5
INDEX
CORNER
NC
NC
P2.5 (A13)
34 NC
42
43
40
41
6
5
444
3
2
26
25
28
27
18
19
20 24
21
22
7
8
9
10
11
12
13
14
15
16
17 29
30
39
38
37
36
35
33
32
31