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Introduction AT89C51 Microcontrollers :

Atmel AT89C51 Microcontroller is an 8-bit microcontroller. it belongs to Atmel’s 8051 families. It has 4 KB of flash or this flash is programmable. It has 128 bytes of RAM. We could erase and program the flash almost 1000 times. In 40-pin Atmel 89C51 IC there are four ports P1, P2, P3, or P0. All ports are 8-bit bidirectional. These ports are used as input or output ports. It is connected to external memory, or P0 needs pull-up resistance. P0 and P2 are used to provide low-byte or high-byte addresses.AT89C51 has serial communication with built-in UART. It has also a different baud rate or it can be programmed according to it. it has two timers. It also has hardware interrupts. In total, it has 6 interrupts.

AT89C51 is an 8-bit microcontroller that belongs to Atmel’s 8051 family. ATMEL 89C51 has 4KB of Flash programmable or erasable read-only memory (PEROM) and 128 bytes of RAM. It could be erased and programmed to a maximum of 1000 times.In 40 pin AT89C51, there are four ports designated as P1, P2, P3, or P0. All these ports are 8-bit bi-directional ports i.e., they could be used as both input or output ports. Except P0 which needs external pull-ups, the rest of the ports have internal pull-ups. When 1s are written to these port pins, they are pulled high by the internal pull-ups and could be used as inputs. These ports are also bit addressable so their bits could also be accessed individually.

Spceifications:

1. Flash Memory: 4K
2. CPU: 8 Bit
3. Maximum Operating Voltage: 6.6V
4. Maximum Oscillator Frequency: 0-24MHz
5. Internal RAM: 128 x 8 Bit

AT89C51 Microcontrollers Pinout Configuration:

1. RST (Pin 9): Reset input (used for initialization and restarting). A reset can occur through two methods: power-on reset and manual reset (by pressing a reset button). It requires that the RST pin remains high for at least 2 machine cycles before transitioning to a low level. This includes a small circuit with resistors and capacitors. The first method is achieved by applying a high voltage to this circuit, while the second method is as simple as pressing a button. Both methods ensure that the RST pin remains high for two machine cycles, completing the reset operation.

2. PSEN (Pin 29): External ROM read signal. PSEN is related to reading data from external ROM. It acts as a condition for reading data, requiring a valid PSEN signal to successfully read data.

2. ALE/PROG (Pin 30): Address latch enable/programming pulse. This pin, also used as PROG during programming, is employed when downloading programs to the microcontroller. It is related to programming pulses and generates specific waveforms during programming.

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Circuit Operation:

8051 Atmel AT89C51 Microcontroller is an 8-bit microcontroller and belongs to the Atmels 8051 family. ATMEL 89C51 has 4KB of Flash programmable or erasable read-only memory (PEROM) and 128 bytes of RAM. It could be erased and programmed to a maximum of 1000 times.

In 40 pin AT89C51, there are four ports designated as P1, P2, P3, or P0. All these ports are eight-bit bi-directional ports i.e. they could be used as both input and output ports. Except for P0 which needs external pull-ups, the rest of the ports have internal of pull-ups. When 1s are written to these port pins, they are pulled high by the internal pull-ups or can be used as inputs. These ports are also a bit addressable so their bits can also be accessed individually.

Port P0 and P2 are also used to provide low-byte and high-byte addresses, respectively, when connected to external memory. Port 3 has multiplexed pins for special functions like serial communication, hardware interrupts, timer inputs, and read/write operations from external memory. AT89C51 has an inbuilt UART for serial of the communication. It could be programmed to operate at different baud rates. Including two timers and hard interrupts, it has a total of six interrupts.

Frequently Asked Questions

Is the AT89C51 the same as the 8051 microcontroller?

The 8051, 89C51, or 89C52 are all microcontrollers that belong to the 8051 family. Here are the major differences between them Architecture or Core: 89C51 and 89C52 have an enhanced version of the 8051 core. Memory of the Size: 89C51 has 4 KB of Flash memory, while 89C52 has 8 KB.

What is the architecture of the Atmel 89C51 microcontroller?

The Atmel AT89C51 is an 8051-based Fully Static 24MHz CMOS of the controller with 32 I/O Lines, 2 Timers/Counters, 6 Interrupts/2 Priority Levels, UART, 3-Level Program Memory Lock, 4K Bytes Flash of the Memory, 128 Bytes On-chip RAM.

What are the special features of the AT89C51 microcontroller?

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 2-level interrupt architecture, a full duplex serial port, an on-chip oscillator, or clock circuitry.

Is the 89c51 microcontroller a pin IC?

In 40 pin AT89C51, there are four ports designated as P1, P2, P3, or P0. All these ports are 8-bit bi-directional ports, i.e., they could be used as both input and output ports. Except for P0 which needs external pull-ups, the rest of the ports have an internal pull-up.

What are the features of the 89c1051 microcontroller?

The AT89C1051 provides the following standard features: 1K Byte of Flash, 64 bytes of RAM, 15 I/O lines, one 16-bit timer/counter, a three-vector 2-level interrupt architecture, a precision analog comparator, an on-chip oscillator, or clock circuitry.

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