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AT89C52 Microcontroller

Image: 
AT89C52 Microcontroller Image
DataSheet: 
 
AT89C52 is an 8-bit microcontroller and belongs to Atmel's 8051 family. AT89C52 has 8KB of Flash programmable and erasable read only memory (PEROM) and 256 bytes of RAM. AT89C52 has an endurance of 1000 Write/Erase cycles which means that it can be erased and programmed to a maximum of 1000 times.
 
Though very slight difference between the features of AT89C51 and AT89C52, they are very similar in their pin configurations* and operations. The differences between AT89C51 and AT89C52 have been tabulated below.
 
 
AT89C52
AT89C51
RAM
256 Bytes
128 Bytes
Flash
8 KB
4 KB
Number of Timers/Counters
3 (16-bit each)
2 (16-bit each)
Number of Interrupt Sources
8
6
 
*The pin configuration of AT89C52 is exactly similar to that of AT89C51 except that the first two pins, P1.0 and P1.1 are multiplexed to correspond to Timer2 operations as given in the following table.
 
Existing
Alternate
Function
P1.0
T2
Timer/counter 2 External Count input
P1.1
T2 EX
Timer/counter 2 Trigger input
 
While AT89C51 has two timers (Timer0 & Timer1), AT89C52 also has Timer2. Corresponding to Timer2, there are extra SFRs (Special Function Registers) T2CON & T2MOD. Also there are registers RCAP2H & RCAP2L to configure 16 bit Capture & Auto-reload modes of Timer2.

 

Pin Diagram: 
AT89C52 Microcontroller Pin diagram, pinout
Pin Description: 
Pin No
Function
Name
1
External count input to Timer/Counter 2, clock-out
T2
P1.0
2
Timer/Counter 2 capture/reload trigger and direction control
T2 EX
P1.1
3
8 bit input/output port (P1) pins
P1.2
4
P1.3
5
P1.4
6
P1.5
7
P1.6
8
P1.7
9
Reset pin; Active high
Reset
10
Input (receiver) for serial communication
RxD
8 bit input/output port (P3) pins
P3.0
11
Output (transmitter) for serial communication
TxD
P3.1
12
External interrupt 1
Int0
P3.2
13
External interrupt 2
Int1
P3.3
14
Timer1 external input
T0
P3.4
15
Timer2 external input
T1
P3.5
16
Write to external data memory
Write
P3.6
17
Read from external data memory
Read
P3.7
18
Quartz crystal oscillator (up to 24 MHz)
Crystal 2
19
Crystal 1
20
Ground (0V)
Ground
21
8 bit input/output port (P2) pins
/
High-order address bits when interfacing with external memory
 
P2.0/ A8
22
P2.1/ A9
23
P2.2/ A10
24
P2.3/ A11
25
P2.4/ A12
26
P2.5/ A13
27
P2.6/ A14
28
P2.7/ A15
29
Program store enable; Read from external program memory
PSEN
30
Address Latch Enable
ALE
Program pulse input during Flash programming
Prog
31
External Access Enable;  Vcc for internal program executions
EA
Programming enable voltage; 12V (during Flash programming)
Vpp
32
8 bit input/output port (P0) pins
 
Low-order address bits when interfacing with external memory
 
P0.7/ AD7
33
P0.6/ AD6
34
P0.5/ AD5
35
P0.4/ AD4
36
P0.3/ AD3
37
P0.2/ AD2
38
P0.1/ AD1
39
P0.0/ AD0
40
Supply voltage; 5V (up to 6.6V)
Vcc


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