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 conven-
tional 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 applications.
8-bit
Microcontroller
with 4K Bytes
Flash
AT89C51
Not Recommended
for New Designs.
Use AT89S51.
Pin Configurations
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
RST
(RXD) P3.0
(TXD) P3.1
(INT0) P3.2
(INT1) P3.3
(T0) P3.4
(T1) P3.5
(WR) P3.6
(RD) P3.7
XTAL2
XTAL1
GND
PDIP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
VCC
P0.0 (AD0)
P0.1 (AD1)
P0.2 (AD2)
P0.3 (AD3)
P0.4 (AD4)
P0.5 (AD5)
P0.6 (AD6)
P0.7 (AD7)
EA/VPP
ALE/PROG
PSEN
P2.7 (A15)
P2.6 (A14)
P2.5 (A13)
P2.4 (A12)
P2.3 (A11)
P2.2 (A10)
P2.1 (A9)
P2.0 (A8)
PQFP/TQFP
P1.4
P1.3
P1.2
P1.1 (T2 EX)
P1.0 (T2)
NC
VCC
P0.0 (AD0)
P0.1 (AD1)
P0.2 (AD2)
P0.3 (AD3)
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
P1.5
P1.6
P1.7
RST
(RXD) P3.0
NC
(TXD) P3.1
(INT0) P3.2
(INT1) P3.3
(T0) P3.4
(T1) P3.5
1
2
3
4
5
6
7
8
9
10
11
PO.4 (AD4)
P0.5 (AD5)
P0.6 (AD6)
P0.7 (AD7)
EA/VPP
NC
ALE/PROG
PSEN
P2.7 (A15)
P2.6 (A14)
P2.5 (A13)
PLCC
P1.4
P1.3
P1.2
P1.1
P1.0
NC
VCC
P0.0 (AD0)
P0.1 (AD1)
P0.2 (AD2)
P0.3 (AD3)
(WR)P3.6
(RD) P3.7
XTAL2
XTAL1
GND
NC
(A8) P2.0
(A9) P2.1
(A10) P2.2
(A11) P2.3
(A12) P2.4
18
19
20
21
22
23
24
25
26
27
28
P1.5
P1.6
P1.7
RST
(RXD) P3.0
NC
(TXD) P3.1
(INT0) P3.2
(INT1) P3.3
(T0) P3.4
(T1) P3.5
7
8
9
10
11
12
13
14
15
16
17
6
5
4
3
2
1
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
PO.4 (AD4)
P0.5 (AD5)
P0.6 (AD6)
P0.7 (AD7)
EA/VPP
NC
ALE/PROG
PSEN
P2.7 (A15)
P2.6 (A14)
P2.5 (A13)
(WR)P3.6
(RD) P3.7
XTAL2
XTAL1
GND
GND
(A8) P2.0
(A9) P2.1
(A10) P2.2
(A11) P2.3
(A12) P2.4
Rev. 0265G–02/00
1
ATMEL [ ATMEL CORPORATION ]
