AT89C52 Microcontroller

Data Sheet : 


AT89C52

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 : 

 

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