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AT89S52 8-bit Microcontroller

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AT89S52 Pin Configuration

Pin Number

Pin Name

Description

1

P1.0 (T2)

Timer/Counter or 0th GPIO pin of PORT 1

2

P1.1 (T2.EX)

Timer/Counter/External Counter or 1st GPIO pin of PORT 1

3

P1.2

2nd GPIO pin of PORT 1

4

P1.3

3rd GPIO pin of PORT 1

5

P1.4

4th GPIO pin of PORT 1

6

P1.5 (MOSI)

MOSI for in System Programming or 5th GPIO pin of PORT 1

7

P1.6 (MISO)

MISO for in System Programming or 6th GPIO pin of PORT 1

8

P1.7 (SCK)

SCK for in System Programming or 7th GPIO pin of PORT 1

9

RST

Making this pin high will reset the Microcontroller

10

P3.0 (RXD)

RXD Serial Input or 0th GPIO pin of PORT 3

11

P3.1 (TXD)

TXD Serial Output or 1st GPIO pin of PORT 3

12

P3.2 (INT0’)

External Interrupt 0 or 2nd GPIO pin of PORT 3

13

P3.3 (INT1’)

External Interrupt 1 or 3rd GPIO pin of PORT 3

14

P3.4 (T0)

Timer 0 or 4th GPIO pin of PORT 3

15

P3.5 (T1)

Timer 1 or 5th GPIO pin of PORT 3

16

P3.6 (WR’)

Memory Write or 6th GPIO pin of PORT 3

17

P3.7 (RD’)

Memory Read or 7th GPIO pin of PORT 3

18

XTAL2

External Oscillator Output

19

XTAL1

External Oscillator Input

20

GND

Ground pin of MCU

21

P2.0(A8)

0th GPIO pin of PORT 2

22

P2.1 (A9)

1st GPIO pin of PORT 2

23

P2.2 (A10)

2nd GPIO pin of PORT 2

24

P2.3 (A11)

3rd GPIO pin of PORT 2

25

P2.4 (A12)

4th GPIO pin of PORT 2

26

P2.5 (A13)

5th GPIO pin of PORT 2

27

P2.6 (A14)

6th GPIO pin of PORT 2

28

P2.7 (A15)

7th GPIO pin of PORT 2

29

PSEN’

Program store Enable used to read external program memory

30

ALE / PROG’

Address Latch Enable / Program Pulse Input

31

EA’ / VPP

External Access Enable / Programming enable Voltage

32

P0.7 (AD7)

Address / Data pin 7 or 7th GPIO pin of PORT 0

33

P0.6 (AD6)

Address / Data pin 6 or 6th GPIO pin of PORT 0

34

P0.5 (AD5)

Address / Data pin 5 or 5th GPIO pin of PORT 0

35

P0.4 (AD4)

Address / Data pin 4 or 4th GPIO pin of PORT 0

36

P0.3 (AD3)

Address / Data pin 3 or 3rd GPIO pin of PORT 0

37

P0.2 (AD2)

Address / Data pin 2 or 2nd GPIO pin of PORT 0

38

P0.1 (AD1)

Address / Data pin 1 or 1st GPIO pin of PORT 0

39

P0.0 (AD0)

Address / Data pin 0 or 0th GPIO pin of PORT 0

40

VCC

Positive pin of MCU (+5V)

 

AT89S52 Microcontroller Features

AT89S52 –Simplified Features

CPU

8-bit PIC

Number of  Pins

40

Operating Voltage (V)

4 to 5.5 V

Number of Programmable I/O pins

32

ADC Module

Nil

Timer Module

16-bit(1)

Comparators

Nil

DAC Module

Nil

Communication Peripherals

UART(1)

External Oscillator

Up to 23Mhz

Internal Oscillator

Nil

Program Memory Type

Flash

Program Memory (KB)

8KB

CPU Speed (MIPS)

-

RAM Bytes

256 x 8-bit

Data EEPROM

Nil

 

Note: The datasheet of the AT89S52 Microcontroller and more detailed Features can be found at the bottom of this page.

 

Other Atmel 8-bit MCU’s

AT89C52, Atmega8A, Attiny1614, Atmega328

 

Brief Intro to AT89S52 Microcontroller

The AT89S52 comes from the popular 8051 family of Atmel Microcontrollers. It is an 8-bit CMOS microcontroller with 8K as Flash memory and 256 bytes of RAM. Since it is similar to the trust worthy 8051 architecture these microcontrollers are as per industry standard. It has 32 I/O pins comprising of three 16-bit timers, external interrupts, full-duplex serial port, on-chip oscillator and clock circuitry.

The Microcontroller also has Operating mode, Idle Mode and Power down mode which makes it suitable for battery operated applications. Few considerable drawback of the microcontroller is that it does not have in-built ADC and does not support SPI or I2C protocols. However you can utilise external modules for the same.

 

Programming AT89S52 Microcontroller

Atmel microcontroller can be programmed with different software's that is available in the market. Arduino, Keil uVision are the most used platforms to name a few. If you are planning on serious programming and expansion with community support then Keil is recommended.

In order to program the Atmel microcontroller we will need an IDE (Integrated Development Environment), where the programming takes place. A compiler, where our program gets converted into MCU readable form called HEX files. An IPE (Integrated Programming Environment), which is used to dump our hex file into our MCUs.

IDE: Keil uVision IDE

Programming Hardware: USB In-circuit programmer (USBASP)

Programmer: USBASP

To dump or upload our code into Atmel IC we need a programmer, the most commonly used programmer is the USBASP which has to be purchased separately. Also simulating you program on software before trying it on hardware will save a lot of time. So you can use software like ISIS proteus from Labcenter to simulate you r programs.

A bare minimum circuit to program an Atmel microcontroller is shown below.

AT89S52 Microcontroller Circuit Diagram

Components associated: USBASP, Crystal oscillators, capacitors, 12V Adapter, 7805 Voltage Regulator.

 

Detailed Features

AT89S52 – Detailed Features

CPU

8-bit 8051 family

Architecture

8

Program Memory Size (Kbytes)

8K Flash

RAM (bytes)

256

EEPROM/HEF

Nil

Pin Count

40

Max. CPU Speed (MHz)

33

Peripheral Pin select (PPS)

No

Internal Oscillator

No

No. Of comparators

2

No. Of  Operational Amplifier

0

No. Of ADC channels

Nil

Max ADC Resolution (bits)

NA

ADC with Computation

No

Number of DAC Converter

0

Max DAC resolution

0

Internal Voltage Reference

NA

Zero Cross Detect

No

No. Of 8-bit timers

0

No. Of 16-bit Timers

3

Signal Measurement Timer

0

Hardware Limit Timer

0

No. Of PWM outputs

0

Max PWM resolution

NA

Angular Timer

No

Math Accelerator

No

No. Of  UART module

1

No. Of SPI Module

0

No. Of I2C module

0

No. Of USB Module

0

Windowed Watchdog Timer (WWDT)

No

CRC/Scan

No

Numerically Controlled Oscillator

0

Cap. Touch Channels

NA

Segment LCD

0

Minimum Operating Temperature (*C)

-55

Maximum Operating Temperature (*C)

125

Minimum Operating Voltage (V)

4

Maximum Operating Voltage (V)

5.5

High Voltage Capable

No

 

How to select your Atmel Microcontroller

Microchip provides a vast variety of Microcontrollers from PIC family and Atmel Family. Their collection has just piled up after Microchip has acquired Atmel. Each MCU has its own advantage and disadvantage. There are many parameters that one has to consider before selecting a MCU for his/her project. The below points are just suggestions which might help one to select a MCU.

  • If you are a beginner who is learning Microcontroller then, selecting a MCU that has good online community support and wide applications will be a good choice. For Atmel AT89S52 or ATmega328 will be a good choice.
  • Consider the operating voltage of your system. If they are 5V then select a 5V MCU some sensors or devices work and communicate on 3.3V in such case a 3.3V MCU can be selected
  • If size and price is a limitation then you can choose small 8-pin MCUs like Attiny1614. These are also comparatively cheaper.
  • Based on the sensors and actuators used in your project, verify which modules you might need in for MCU. For example is you are reading many Analog voltages then make sure MCU has enough ADC channels and supportive resolution. The details of all modules are given in the table above.
  • If you project involves communication protocols like UART, SPI ,I2C, CAN etc make sure you MCU can support them. Some MCU can support more than one module of the same protocol

 

Applications

  • Multiple DIY Projects
  • Very good choice if you are learning ATmel
  • Projects requiring Multiple I/O interfaces and communications
  • Replacement for Arduino Module
  • Ideal for more advanced level A/D applications in automotive, industrial, appliances and consumer applications.

 

2D Model (PSDIP)

AT89S52 Microcontroller Dimensions




Download Datasheet PDF:
AT89S52 Microcontroller Datasheet