AT89C51 Microcontroller: Pin Description, Datasheet, Programming
4KB 4K x 8 FLASH 80C51 8-Bit Microcontroller 89C Series 40-DIP (0.600, 15.24mm)









4KB 4K x 8 FLASH 80C51 8-Bit Microcontroller 89C Series 40-DIP (0.600, 15.24mm)
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer This post will unlock more details about AT89C51. There is a huge range of Semiconductors, Capacitors, Resistors and ICs in stock. Welcome RFQ.

How to Program 8051 ICs of ATMEL (2/3)
AT89C51 Pinout
AT89C51 Pinout
Pin description is shown below:
Pin Number | Pin Name | Description |
1 | P1.0 | 0th pin of PORT P1 |
2 | P1.1 | 1st pin of PORT P1 |
3 | P1.2 | 2nd pin of PORT P1 |
4 | P1.3 | 3rd pin of PORT P1 |
5 | P1.4 | 4th pin of PORT P1 |
6 | P1.5 | 5th pin of PORT P1 |
7 | P1.6 | 6th pin of PORT P1 |
8 | P1.7 | 7th pin of PORT P1 |
9 | RST | Reset pin of the Microcontroller |
10 | (RXD) P3.0 | 0th pin of PORT P3 or Receiver pin of Microcontroller |
11 | (TXD) P3.1 | 1st pin of PORT P3 or Transmitter pin of Microcontroller |
12 | (INT0) P3.2 | 2nd pin of PORT P3 or External Interrupt 0 of MCU |
13 | (INT1) P3.3 | 3rd pin of PORT P3 or External Interrupt 1 of MCU |
14 | (T0) P3.4 | 4th pin of PORT P3 or Timer 0 interrupt of MCU |
15 | (T1) P3.5 | 5th pin of PORT P3 or Timer 1 interrupt of MCU |
16 | (WR) P3.6 | 6th pin of PORT P3 or Write to External data memory pin |
17 | (RD) P3.7 | 7th pin of PORT P3 or Read from External data memory pin |
18 | XTAL2 | External crystal pin 2 of Microcontroller |
19 | XTAL1 | External crystal pin 1 of Microcontroller |
20 | GND | Ground pin of MCU |
21 | P2.0(A8) | 0th pin of PORT P2 or High-order Address bit 8 of MCU |
22 | P2.1(A9) | 1st pin of PORT P2 or High-order Address bit 9 of MCU |
23 | P2.2(A10) | 2nd pin of PORT P2 or High-order Address bit 10 of MCU |
24 | P2.3(A11) | 3rd pin of PORT P2 or High-order Address bit 11 of MCU |
25 | P2.4(A12) | 4th pin of PORT P2 or High-order Address bit 12 of MCU |
26 | P2.5(A13) | 5th pin of PORT P2 or High-order Address bit 13 of MCU |
27 | P2.6(A14) | 6th pin of PORT P2 or High-order Address bit 14 of MCU |
28 | P2.7(A15) | 7th pin of PORT P2 or High-order Address bit 15 of MCU |
29 | PSEN | Program store enable pin, Read external program memory |
30 | ALE/PROG | Address Latch Enable/ Program Pulse input for flashing |
31 | EA/VPP | Access Enable voltage/Program enable voltage |
32 | P0.7(AD7) | 7th pin of PORT P0 or Low-order Address bit 7 of MCU |
33 | P0.6(AD6) | 6th pin of PORT P0 or Low -order Address bit 6 of MCU |
34 | P0.5(AD5) | 6th pin of PORT P0 or Low -order Address bit 5 of MCU |
35 | P0.4(AD4) | 6th pin of PORT P0 or Low -order Address bit 4 of MCU |
36 | P0.3(AD3) | 3rd pin of PORT P0 or Low -order Address bit 3 of MCU |
37 | P0.2(AD2) | 2nd pin of PORT P0 or Low -order Address bit 2 of MCU |
38 | P0.1(AD1) | 1st pin of PORT P0 or Low -order Address bit 1 of MCU |
39 | P0.0(AD0) | 0th pin of PORT P0 or Low -order Address bit 0 of MCU |
40 | Vcc | Supply pin of MCU |
AT89C51 CAD Model
Symbol
AT89C51 Symbol
Footprint
3D Model
AT89C51 3D Model
AT89C51 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 conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer that provides a highly-flexible and cost-effective solution to many embedded control applications.
AT89C51 Feature
• 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
AT89C51 Application
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
AT89C51 Block Diagram
AT89C51 Block Diagram
How to Program the AT89C51 (8051) Microcontroller
How to Program the AT89C51 Microcontroller
The Atmel microcontroller can be programmed using a variety of software available on the market. The most popular platforms are Arduino and Keil µVision, to mention a few. Keil is recommended if you want to do serious programming and expand with community help.
To program the Atmel microcontroller, we'll need an IDE (Integrated Development Environment), which acts as a programming environment. A compiler converts our software into HEX files, which can be read by MCUs. Our hex file is dumped into our MCUs using an IPE (Integrated Programming Environment).
IDE: Keil µVision IDE
Programming Hardware: MAX232 with RS232 to USB converter
Programmer: USBASP
A programmer is required to dump or upload our code into an Atmel IC; the most often used programmer is the USBASP, which must be purchased separately. Simulating your program in software before attempting it on hardware will also save you time. As a result, you can simulate your applications using software such as Labcenter's ISIS proteus.
AT89C51 Programming circuit is shown below:
AT89C51 Programming circuit
Parts with Similar Specs
Specifications
- TypeParameter
- Mounting Type
The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.
Through Hole - Package / Case
refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.
40-DIP (0.600, 15.24mm) - Supplier Device Package
The parameter "Supplier Device Package" in electronic components refers to the physical packaging or housing of the component as provided by the supplier. It specifies the form factor, dimensions, and layout of the component, which are crucial for compatibility and integration into electronic circuits and systems. The supplier device package information typically includes details such as the package type (e.g., DIP, SOP, QFN), number of pins, pitch, and overall size, allowing engineers and designers to select the appropriate component for their specific application requirements. Understanding the supplier device package is essential for proper component selection, placement, and soldering during the manufacturing process to ensure optimal performance and reliability of the electronic system.
40-PDIP - Number of I/Os32
- Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
0°C~70°C TA - Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Tube - Series
In electronic components, the "Series" refers to a group of products that share similar characteristics, designs, or functionalities, often produced by the same manufacturer. These components within a series typically have common specifications but may vary in terms of voltage, power, or packaging to meet different application needs. The series name helps identify and differentiate between various product lines within a manufacturer's catalog.
89C - Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
Obsolete - Moisture Sensitivity Level (MSL)
Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures
3 (168 Hours) - Oscillator Type
Wien Bridge Oscillator; RC Phase Shift Oscillator; Hartley Oscillator; Voltage Controlled Oscillator; Colpitts Oscillator; Clapp Oscillators; Crystal Oscillators; Armstrong Oscillator.
Internal - Speed
In electronic components, "Speed" typically refers to the rate at which data can be processed or transferred within the component. It is a measure of how quickly the component can perform its functions, such as executing instructions or transmitting signals. Speed is often specified in terms of frequency, such as clock speed in processors or data transfer rate in memory modules. Higher speed components can perform tasks more quickly, leading to improved overall performance in electronic devices. It is an important parameter to consider when designing or selecting electronic components for specific applications.
24MHz - RAM Size
RAM size refers to the amount of random access memory (RAM) available in an electronic component, such as a computer or smartphone. RAM is a type of volatile memory that stores data and instructions that are actively being used by the device's processor. The RAM size is typically measured in gigabytes (GB) and determines how much data the device can store and access quickly for processing. A larger RAM size allows for smoother multitasking, faster loading times, and better overall performance of the electronic component. It is an important factor to consider when choosing a device, especially for tasks that require a lot of memory, such as gaming, video editing, or running multiple applications simultaneously.
128 x 8 - Voltage - Supply (Vcc/Vdd)
Voltage - Supply (Vcc/Vdd) is a key parameter in electronic components that specifies the voltage level required for the proper operation of the device. It represents the power supply voltage that needs to be provided to the component for it to function correctly. This parameter is crucial as supplying the component with the correct voltage ensures that it operates within its specified limits and performance characteristics. It is typically expressed in volts (V) and is an essential consideration when designing and using electronic circuits to prevent damage and ensure reliable operation.
4V~6V - Core Processor
The term "Core Processor" typically refers to the central processing unit (CPU) of a computer or electronic device. It is the primary component responsible for executing instructions, performing calculations, and managing data within the system. The core processor is often considered the brain of the device, as it controls the overall operation and functionality. It is crucial for determining the speed and performance capabilities of the device, as well as its ability to handle various tasks and applications efficiently. In modern devices, core processors can have multiple cores, allowing for parallel processing and improved multitasking capabilities.
80C51 - Program Memory Type
Program memory typically refers to flash memory when it is used to hold the program (instructions). Program memory may also refer to a hard drive or solid state drive (SSD). Contrast with data memory.
FLASH - Core Size
Core size in electronic components refers to the physical dimensions of the core material used in devices such as inductors and transformers. The core size directly impacts the performance characteristics of the component, including its inductance, saturation current, and frequency response. A larger core size typically allows for higher power handling capabilities and lower core losses, while a smaller core size may result in a more compact design but with limitations on power handling and efficiency. Designers must carefully select the core size based on the specific requirements of the application to achieve optimal performance and efficiency.
8-Bit - Program Memory Size
Program Memory Size refers to the amount of memory available in an electronic component, such as a microcontroller or microprocessor, that is used to store program instructions. This memory is non-volatile, meaning that the data stored in it is retained even when the power is turned off. The program memory size determines the maximum amount of code that can be stored and executed by the electronic component. It is an important parameter to consider when selecting a component for a specific application, as insufficient program memory size may limit the functionality or performance of the device.
4KB 4K x 8 - Connectivity
In electronic components, "Connectivity" refers to the ability of a component to establish and maintain connections with other components or devices within a circuit. It is a crucial parameter that determines how easily signals can be transmitted between different parts of a circuit. Connectivity can be influenced by factors such as the number of input and output ports, the type of connectors used, and the overall design of the component. Components with good connectivity are essential for ensuring reliable and efficient operation of electronic systems.
UART/USART - RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
Non-RoHS Compliant
Datasheet PDF
- Datasheets :
AT89C51 Package
AT89C51 Package
AT89C51 Manufacturer
Rochester Electronics ranks as a global leading semiconductor provider. Due to their products' characteristics of high quality and durability, these products are suitable for long-term production and maintenance in the fields of industry, transportation and high-reliability markets. Their large inventory includes more than 100,000 products and 15 billion units, making them exceed other companies in terms of selection, capabilities, or solutions.
What is AT89C51?
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.
What is the difference between 8051 and 89C51 microcontroller?
Basically, the difference is that 8051 is the original one, 89C51 is one of the many 8051 families. If you are starting a new product, I strongly recommend you to use 89C51 (Atmel) or 89V51(NXP).
What is difference between 89c51 and 89s52?
Difference between 89s52 & 89c51 First of all both microcontroller has been discontinued by Atmel. If your design is based on 89C51, you don't have to worry if it's changed later with 89C52. No changes are to be performed, neither software nor hardware (some minor settings in the hardware programmer device).
Is AT89C51 a 8051?
The Atmel AT89C51 is an 8051-based Fully Static 24MHz CMOS controller with 32 I/O Lines, 2 Timers/Counters, 6 Interrupts/2 Priority Levels, UART, Three-Level Program Memory Lock, 4K Bytes Flash Memory, 128 Bytes On-chip RAM.
What is clock frequency in AT89C51 microcontroller?
8 Bit MCU, 8051 Family AT89C51 Series Microcontrollers, 40 MHz, 32 KB, 1 KB, 44 Pins, VQFP.
What is the size of bank registers space in RAM & Flash Memory in AT89C51?
The AT89C51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full-duplex serial port, on-chip oscillator and clock circuitry.
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