An All-Encompassing Guide To 8051 Microcontroller Architecture

Introduction to 8051 Microcontrollers

8051 microcontroller is an 8-bit family of microcontrollers developed by Intel in the early 1980s. It's a low-cost and read-only memory (ROM) based controller with powerful processing capabilities. It has been extensively used for a wide range of applications, such as industrial automation, consumer appliances, medical devices, etc.

Features of 8051 Microcontroller

• 8-bit architecture with 8-bit registers and an 8-bit accumulator.
• 4K bytes of programmable ROM, 128 bytes of RAM.
• 16 I/O lines are available.
• Two timers and one serial port are available.
• Can be easily interfaced with external peripherals like LCD, printer, etc.
• Operating voltage range of 2.4V to 6V.
• 8 interrupts are available.

Block Diagram of 8051 Microcontroller

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Pin Description of 8051 Microcontroller

• P0.0-P0.7: These are 8-bit bidirectional I/O lines which can be used for parallel data transfer.
• P1.0-P1.7: These are 8-bit bidirectional I/O lines which can be used for parallel data transfer.
• P2.0-P2.7: These are 8-bit bidirectional I/O lines which can be used for various other purposes like interrupt, timer, etc.
• P3.0-P3.7: These are 8-bit bidirectional I/O lines which can be used for various other purposes like communication protocol, serial data transfer, etc.
• Vcc: This is the positive supply pin used to provide power to the microcontroller.
• GND: This is the ground pin used to complete the circuit.
• ALE: This is the address latch enable pin used to transfer upper address byte on P0 and P1 pins.
• PSEN: This is the program store enable pin used to provide memory access control signal.
• EA/VPP: This is the external access/program pulse pin used to provide access to external program memory.
• INT0: This is the external interrupt 0 pin used to trigger an interrupt on the rising edge of its input.
• INT1: This is the external interrupt 1 pin used to trigger an interrupt on the falling edge of its input.
• T0: This is the timer 0 external input pin which can be used for various applications like timing and counting.
• T1: This is the timer 1 external input pin which can be used for various applications like timing and counting.
• RXD: This is the receive pin used to receive data from the external source.
• TXD: This is the transmit pin used to transmit data to the external source.
• WR: This is the write pin used to write data to the internal memory.
• RD: This is the read pin used to read data from the internal memory.