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.
(continued)
8-Bit
Microcontroller
with 4K Bytes
Flash
AT89C51
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
X TA L 2
X TA L 1
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
(AD0)
(AD1)
(AD2)
(AD3)
44 42 40
38
36 34
43 41 39
37
35
P1.5
P1.6
P1.7
RST
P3.0
NC
P3.1
P3.2
P3.3
P3.4
P3.5
P1.4
P1.3
P1.2
P1.1
P1.0
NC
VCC
P0.0
P0.1
P0.2
P0.3
INDEX
CORNER
(RXD)
(TXD)
(INT0)
(INT1)
(T0)
(T1)
1
2
3
4
5
6
7
8
9
10
11
13 15 17 19 21
12 14 16 18 20 22
33
32
31
30
29
28
27
26
25
24
23
P0.4 (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
(AD0)
(AD1)
(AD2)
(AD3)
(RXD)
(TXD)
(INT0)
(INT1)
(T0)
(T1)
P1.5
P1.6
P1.7
RST
P3.0
NC
P3.1
P3.2
P3.3
P3.4
P3.5
6
4
2
44 42 40
1
3
4 3 4 13 9
7 5
8
38
9
37
10
36
11
35
12
34
13
33
14
32
15
31
16
30
1 7 1 9 2 1 2 3 2 5 2 72 9
18 20 22 24 26 28
(WR) P3.6
(RD) P3.7
X TA L 2
X TA L 1
GND
NC
(A8) P2.0
(A9) P2.1
(A10) P2.2
(A11) P2.3
(A12) P2.4
P1.4
P1.3
P1.2
P1.1
P1.0
NC
VCC
P0.0
P0.1
P0.2
P0.3
INDEX
CORNER
P0.4 (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
X TA L 2
X TA L 1
GND
GND
(A8) P2.0
(A9) P2.1
(A10) P2.2
(A11) P2.3
(A12) P2.4
0265F-A–12/97
4-29
ATMEL [ ATMEL CORPORATION ]
