Introduction to 8051 Microcontroller

Hi, readers welcome to the new post. In today’s tutorial, we will have a detailed look at Introduction to 8051 Microcontroller. The first time this microcontroller was created by the Intel in 1980. Its structure is based on Harvard Architecture and was created to be employed in the embedded system. Firstly it was manufactured with the use of the NMOS technique but this technique was expensive and uses a lot of power so Intel replaced this technique with the CMOS and created a new version that has the letter C for the difference from the previous controller and is written as 80C51.

So the controllers that are currently created and used in different engineering simulations use less power due to creation through the CMOS technique. There are 2 types of Buses used in this module first is for program and second for data transmission. So it consists of 2 storage spaces used for to store programs and data of sixty-four-kilo bytes. In today’s post, we will have a detailed look at its working, operation, pinouts, and some other related factors. So let’s get started with Introduction to 8051 Microcontroller.

Introduction to 8051 Microcontroller

• The 8051 Microcontroller is Ic which is incorporated with forty pinouts and has a central processing unit with other devices such as random access memory, and read-only memory.

• The space of ROM used in this module is four kilobytes and the space of ROM is one twenty byte with that it has two sixteen-bit timers,
• There are four parallel eight-bit port exits in this device which can be programmed according to the requirements of the project.
• The crystal oscillator is assembled on this board having a frequency of twelve megahertz.
• Previous models of this module used assembly language but the new version used C, and javascript languages.
• Like other controllers, these modules are not created through the NMOS technique but constructed with the CMOS.
• The common packaging in which it exits is DIP, forty-four lead TQFP, forty-four lead PLCC.

Pinout of 8051 Microcontroller

• These are forty pinouts of 8051 Microcontrollers which are discussed here.

Pinout 40 

• it is denoted as Vcc and five volts are given to this pinout.

Pinouts 32 to 39

• these pinouts belong to Port Zero and operate as input and output pinouts.

Pinout 31

• This pinout is used to enable or disable the exterior memory interfacing.

Pinout 30

• it is ALE or aka address latch that enables pinout which used to demultiplex the address-data signal at port zero.

Pinout 29

• It is PSEN pinout which used to read signals from the exterior memory unit.

Pinout 21 to 28

• This group of pinout belongs to port 2 and used as input and output.

Pinout 20

• It is Vss and used for the ground connection.

Pinout 18,19

• Through these 2 pins, the exterior clock is given to the module.

Pinout 10 to 17

• This group of pinout belongs to port 3.

Pinout 9

• It is reset pinout

Pinout 1 to 8

• These pinouts belong to the port one and operate as input and output pins.

8051 Microcontroller Ports

• There total 4 ports exist in the 8051 microcontroller and each comes with 8 pins.

Port 0

• In this port, pins are from 32 to 39 and are two-direction pins

Port 1.

• This port comes with Pin 1 to 8 and they are also bidirectional

Port 2.

• In this port, pins are from 21 to 28 and used as higher addresses or data buses.

Port 3.

• This port has pins from 10 to 17

8051 Microcontroller Structure

• In the below figure inner structure of 8051 is shown let’s discuss it with detail.

CPU

• The central processing unit is the brain of the controller. All tasks performed by the controller is managed through this part. OVer operation of CPU, there is no influence of the user. The interpretation of the information stored in the read-only memory is done through this part and execute the specified operation.
• All types of registers used in the controller are controlled by the CPU.

Interrupts:

• In some cases, we need to stop the continued process and execute the coming process for these interrupts to be used.
• There are 5 types of interrupts used in the structure of the 8051 controllers which are INT0, TF0, INT1, TF1, R1/T1.
• These interrupts create some time intervals in the execution of the main program. TF0 and TF1 are timers interrupts and  INT0 and INT1 are exterior interrupts. While R1/T1 is a serial port interrupt.

Memory Unit

• Above we discussed that CPU is used for the execution of different commands. To store these commands memory is used. there are 2 types of memory units used in the controller Random access memory and read-only memory.
• The storing space of read-only memory is four-kilo bytes and the storage of random access memory is one twenty bytes.
• The instruction stored in the ROM is called code. ROM is non-volatile memory it stores data for large time intervals when the power applied is off.
• Random-access memory is a volatile memory that retains data for a short time and it needed a regular power supply for data storage.

RAM 

•  128-byte RAM for data storage.

ROM 

•  4KB ROM is available for program storage.

Serial Port

• For serial communication in the 8051 controllers, the UART port is used. It operates in 2 ways can send and receive data.
• There are 3 pinout exits in the serial port transmitter, receiver, and ground.

Applications of 8051 Microcontroller

• These are some important applications of 8051 microcontrollers.
• It used in different types of industrial projects.
• To control the different processes it used.
• It also exits in different electronic devices such as Tv, VCR, video games.
• It has security circuits and Automattic operating devices.
• It is used in different temperature detection devices.
• The parking indicator comprises this module.
• In a fire detector, this module is used.
• Speed control of dc motor can be done with this device.

Difference between 8051 and PIC

Feature	8051	PIC
Structure	8-bit	8-bit or 16-bit
CPU Speed	33 MHz	32 MHz
Interrupt handling	Simple and limited	complex
Development tools	available and matur	Growing
Cost	Lower	Lower
Power Use	High	Low
Instruction Set	Limited	complex
On-chip memory	Limited	larger on-chip memory
On-chip peripherals	Limited	diverse on-chip peripherals
Bus	8 bit for standard core.	8-bit/16-bit/32-bit
Speed	slower	Fast
Architecture	Von Neumann architecture.	Harvard architecture.
Memory types	ROM, SRAM, FLASH memory.	SRAM, FLASH memory.
communication protocols.	UART, USART, SPI, I2C	PIC, LIN, UART, Ethernet, I2S, SPI USART, CAN,
clock	12 clock per instruction cycle.	4 clock per instruction cycle.
Types	AT89S52, AT89C1051,  AT89C51, AT89C52, AT89S51, AT89C2051.	PIC18fXX8,  PIC32MXX. PIC16f88X,

8051 Family Members

Feature	8051	8052	8031
ROM(bytes)	4K	8K	0K
Serial port	1	1	1
Interrupt sources	6	8	6
RAM(bytes)	128	256	128
Timers	2	3	2
I/O pins	32	32	32

 8051 vs AVR Microcontrollers

Features	8051	AVR
Architecture	8-bit	8-bit or 32-bit
CPU Speed	33 MHz	20 MHz
On-chip peripherals	Limited	More
Interrupt handling	Simple	More complex
Cost	Lower	Less then some ARM and MSP430)
Power Consumption	Higher	Low power
Instruction Set	Limited	Complex
On-chip memory	Limited memory	Larger on-chip memory

Difference between 8051 and MSP430

Features	8051	MSP430
Architecture	8-bit micro-controller.	16-bit micro-controller.
Ram	128 bytes of internal RAM. Some new models come with 256 bytes of RAM.	28/256/512 Bytes RAM/SRAM.
Power mode	, no power-saving modes.	5 power saving modes.
Functions	Multiplications and MAC operations are done in software	Hardware multiplier and MAC units
Family	8051 variants.	MSP430X, MSP430FR57xx, MSP430x1xx to x6xx series.
The price	cost is very low.	average.
Types	Micro-controllers AT89C51, P89v51, etc.	Micro-controller MSP430G2553, MSP430 launchpad.
Manufacturer	NXP, Atmel, , Cyprus, Infineon, Silicon Labs, Dallas, etc.	Texas Instrument.
Rom	ROM size is internally 4KB to 64KB.	2/4/8/16 KB to 32 KB.
Word instructin	No word instruction	Word and byte instructions exist
Bit instruction	special bit type instructions	No bit of instruction.
Work for	digital signal.	mixed signals.
CLock	12 clock/instruction cycle.	6 clock/instruction cycle.
Power use	average power use	very low.

Limitations of 8051 Microcontroller

• It comes with a limited range of program memory and data memory that are 4KB and 128 bytes or 256 bytes respectively. So limited value does not make it best for complicated circuits that need high memory space.
• It has less processing power than another controller such as a clock speed is 12 MHz to 24 MHz. So not used for high processing power projects.
• It has limited pins and other peripherals so not used for a larger number of device connections.
• It not have high security features and provides low memory protection and encryption.

Application of 8051 Microcontroller

• Automation system
• Medical Devices:
• Energy management system
• Touch Screen:

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That is a detailed post about 8051 microcontrollers if you have any queries ask in comments. Thanks for reading. have a good day.