89C51 or AT89C51 is an 8-bit microcontroller and belongs to Atmel’s family . Pdf of AT89C51 datasheet & pin diagram are also available at Engineers. AT89CPI Microchip Technology / Atmel 8-bit Microcontrollers – MCU UNSAWN WAFER 21 MIL BACKGRIND 89C51 – 24MHZ, PDIP, IND TEMP datasheet. Disclaimer: Whilst information is supplied in good faith, we are not liable for any errors or omissions. Please consult the relevant Atmel datasheet. E&OE. Key.

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But, since the AT89C51 has a strong community support if your motive is to learn embedded then AT89C51 can still be a good choice. The moment a byte is written into SBUF, it is framed with the start and stop bits and transferred serially via the TxD pin. SPI Module of Arduino. It can be erased and program to a maximum of times. Notice that in flash memory you must erase the entire contents of ROM in order to program it again. Similarly, when the bits are received serially via RxD, the 89C51 deframes it by eliminating the stop and start bits, making a byte out of the data received, and then placing it in the SBUF.

Answer Tips Double click any word to see the meaning. See the following table for its specs The block diagram shows the internal structure of the microcontroller AT89C51; Pin description of this MCU can be seen in the following diagram; Port 0 ; is a dual-purpose port on pins of the 1C.

For larger designs with external memory, it becomes a multiplexed address and data bus. The rest must be accessed in byte format.

Since the 89C51 has an 8-bit architecture, each bit timer is accessed as two separate registers of low byte and high byte. Please give your valuable comments for further improvements.

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Submitted by webmaster on 14 May Mode 2 Programming; The following are the characteristics and operations of mode 2. These registers are accessible in the same way as the registers of timer 0. With an 8-bit data type, any data larger than 8 bits must be broken into 8-bit chunks before it is processed.

What is Web Browser. Set by hardware halfway through the stop bit time in mode1.

The accumulator, register A, is used for all arithmetic and logic instructions. In each case, the lower 2 ah89c51 are used to set the timer mode and the upper 2 bits to specify the operation.

It works with the popular architecture and hence is used by most beginners till date.

AT89C51 Microcontroller

When 1s are written to these port pins, they are pulled high by the internal pull-ups and can be datashet as inputs. All the registers of 89C51 are; Timers; Both timer 0 and timer 1 are 16 bits wide.

The below points are just suggestions which might help one to select a MCU. All the registers of 89C51 are.

Reset pin; Active high. All come with on-chip ROM to store programs. It counts up until it reaches its limit of FFH. This mode has many applications, including setting the baud rate in serial communication.


The low byte register is called TL0 timer 0 low byte and the high byte register is referred to as th0 timer 0 high byte. AT89C51 is an 8-bit microcontroller and belongs to Atmel’s family.

Program pulse input during Flash nicrocontroller. They are addressed as 0 to in decimal or 00 to 7FH. In other words, the multiplexes address and data through port 0 to save pins.


Atmel AT89C51

Instead the new AT89S51 is recommended for new applications. In the there is only one data type: For normal operation, RST is low. However, it has an auto-reloading capability in auto reload. If you are planning on serious programming and expansion with community support then Keil is recommended. Could you pls upload them again? For this reason the AT89C51 is used in place of the to eliminate the waiting time needed to erase the chip and thereby speed up the development time.

ATMEL 89C51 | AT89C51 Microcontroller Pin Diagram & Description

Quartz crystal oscillator up to 24 MHz. Figure shows permanent connections of Reset Pin. This erasing of flash is done by the PROM burner itself. These registers can also be read like any other register. It can be programmed to operate at datashheet baud rates. In order to program the Atmel microcontroller we will need an IDE Integrated Development Environmentwhere the programming takes place. TL — Programmable Reference Voltage. Arduino, Keil uVision are the most used platforms to name a few.

TH is loaded with the initial count and a copy of it is given to TL.

AT89CPC – AT89C51 Pin 24MHz 4kb 8-bit Microcontroller Technical Data

Port 0 ; is a dual-purpose port on pins of the 1C. All these ports are 8-bit bi-directional ports, i. It has on chip ROM in the form of flash memory. GND; Pin 20 is the Ground pin. Registers; In the CPU, registers are used to store information temporarily. Skip to main miccrocontroller.