Types of Microcontrollers

 

What is a Microcontroller?  A microcontroller is a small, low-cost and self contained computer-on-a-chip that can be used as an embedded system. A few microcontrollers may utilize four-bit expressions and work at clock rate frequencies, f requencies, which usually include:      

           

An 8 or 16 bit microprocessor. A little measure of RAM. Programmable ROM and flash memory. Parallel and serial I/O. Timers and signal generators. Analog to Digital and Digital to Analog conversion

Microcontrollers usually must have low-power requirements r equirements since many devices they control are battery-operated. Microcontrollers are used in many consumer electronics, car engines, computer peripherals and test or measurement equipment. f or long lasting battery applications. The dominant part of  And these are well suited for microcontrollers being used now a days are implanted in other apparatus.

How are Microcon Microcontrollers trollers Classified? The microcontrollers are characterized regarding bus-width, instruction set, and memory structure. For the same family, there may be different forms with different sources. This article is going to describe some of the basic types of the Microcontroller that newer users may not know about. The types of microcontroller is shown in figure, they are characterized by their bits, memory architecture, memory/devices and instruction set. Let’s discuss briefly about it.

Types of Microcontrollers

 

Classification According According to Number of Bits The bits in microcontroller are 8-bits, 16-bits and 32-bits microcontroller. In 8-bit 8-bit  microcontroller, the point when the internal bus is 8-bit 8 -bit then the ALU is performs the arithmetic and logic operations. The examples of 8-bit microcontrollers are Intel 8031/8051, PIC1x and Motorola MC68HC11 families. The 16-bit 16-bit microcontroller  microcontroller performs greater precision and performance as compared to 8-bit. For example 8 bit microcontrollers can only use 8 bits, resulting in a final range of 0×00 –  0xFF (0-255) for every cycle. In contrast, 16 bit microcontrollers with 0×00 – 0xFF its 16 bit data width has a range of 0×0000  –  – 0xFFFF  0xFFFF (0-65535) for every cycle. A longer timer most extreme worth can likely prove to be useful in certain applications and circuits. It can automatically operate on two 16 bit numbers. Some examples of 16-bit microcontroller are 16-bit MCUs are extended 8051XA, PIC2x, Intel 8096 and Motorola MC68HC12 families. The 32-bit 32-bit microcontroller  microcontroller uses the 32-bit instructions to perform the arithmetic and logic operations. These are used in automatically controlled devices including implantable medical devices, engine control systems, office machines, appliances and other types of embedded systems. Some examples are Intel/Atmel 251 family, PIC3x.

Classification According According to Memory Devices The memory devices are divided into two types, they are  

   

Embedded memory microcontroller External memory microcontroller

Embedded memory microcontroller : When an embedded system has a microcontroller unit that has all the functional blocks available on a chip is called an embedded microcontroller. For example, 8051 having program & data memory, I/O ports, serial communication, counters and timers and interrupts on the chip is an embedded microcontroller. External

Memory

Microcontroller :

When

an

embedded

system

has

a

microcontroller unit that has not all the functional blocks available on a chip is called

 

an external memory microcontroller. For example, 8031 has no program memory on the chip is an external memory microcontroller.

Classification According According to Instruction Set CISC:: CISC is a Complex Instruction Set Computer. It allows the programmer to use CISC one instruction in place of many simpler instructions. RISC:: The RISC is stands for Reduced Instruction set Computer, this type of RISC instruction sets reduces the design of microprocessor for industry standards. It allows each instruction to operate on any register or use any addressing mode and simultaneous access of program and data. Example for CISC and RISC:  RISC:   CISC:

Mov AX, 4

RISC:

Mov BX, 2   ADD BX, AX   Begin   Loop   From above example, RISC systems shorten execution time by reducing the clock

cycles per instruction and CISC systems shorten execution time by reducing the number of instructions per program. The RISC gives a better execution than the CISC.

Classification According According to Memory Architecture Memory architecture of microcontroller are two types, they are namely:  

   

Harvard memory architecture microcontroller Princeton memory architecture microcontroller

Harvard Memory Architecture Microcontroller : The point when a microcontroller unit has a dissimilar memory address space for the program and data memory, the microcontroller has Harvard memory architecture in the processor. Princeton Memory Architecture Microcontroller : The point when a microcontroller has a common memory address for the program memory and data memory, the microcontroller has Princeton memory architecture in the processor.

Mov A

Mov B Mov C ADD A Begin

 

5 Applications of Microcontrollers Microcontroller has many applications electronic equipment’s  equipment’s    

 

     

Mobile Phones Auto Mobiles Washing Machines

   

Cameras Security Alarms

4 Types of Microcontro Microcontrollers llers Microcontroller 8051  8051  It is a 40pin microcontroller with Vcc of 5V connected to pin 40 and Vss at pin 20 which is kept 0V. And there are input and output ports from P1.0  –  – P1.7  P1.7 and which having open drain feature. Port3 has got extra features. Pin36 has open drain condition and pin17 has internally pulled up transistor inside the microcontroller. When we apply logic 1 at port1 then we get logic 1 at port21 and vice versa. The programming of microcontroller is dead complicate. Basically we write a program in C-language which is next converted to machine language understand by the microcontroller. A RESET pin is connected to pin9, connected with a capacitor. When the switch is ON, the capacitor starts charging and RST is high. Applying a high to the reset pin resets the microcontroller. If we apply logic zero to this pin, the program starts execution from the beginning. Memory Architecture of 8051  8051 

The memory of 8051 is divided to two parts.They are Program Memory and Data Memory. Program Memory stores the program being executed whereas Data Memory temporarily stores the data and the results. The 8051 has been in use in a wide number of devices, mainly because it is easy to integrate into a device. Microcontrollers are mainly used in energy management, touch screen, automobiles, and medical devices.

 

Program Memory of 8051

 And 

Data Memory of 8051

Pin Description of 8051 Microcontroller   Pin-40: Vcc

is the main power source of +5V DC.

 Vss –  – it  it Pin 20: Vss

represents ground (0 V) connection.

Pins 32-39: Known Pin-31: Address

as Port 0 (P0.0 to P0.7) to t o serving as I/O ports.

Latch Enable (ALE) is used to demultiplex the address-data signal

of port 0. Pin-30: (EA)

External Access input is used to enable or disable external memory

interfacing. If there is no external memory requirement, this pin is always held high. Pin- 29: Program

Store Enable (PSEN) is used to read signal from external program

memory. Pins- 21-28: Known

as Port 2 (P 2.0 to P 2.7) – 2.7) – in  in addition to serving as I/O port,

higher order address bus signals are multiplexed with this quasi bi directional port. Pins 18 and 19: Used Pins 10  –  17:  17: This

to interfacing an external crystal to provide system clock.

port also serves some other functions like interrupts, timer input,

control signals for external memory interfacing Read and Write. This is a quasi

 

bidirectional port with internal pull up. Pin 9: It

is a RESET pin, used to set the 8051 microcontroller to its initial values,

while the microcontroller is working or at the initial start of application. The RESET pin must be set high for 2 machine cycles. Pins 1  –  8:  8: This

port does not serve any other functions. Port 1 is a quasi bi

directional I/O port.

Microcontrollerr Renesas Microcontrolle Renesas is latest automotive microcontroller family that offers high performance feature with exceptionally low power consumption over a wide and versatile extend of items. This microcontroller offers rich functional security and embedded safety characteristics required for new and advanced automotive applications. The core structure of microcontroller CPU support high reliability and high performance requirements. The Renesas microcontroller offering low power, high performance, modest packages and the largest range of memory sizes combined together with characteristics rich peripherals.

Renesas

Renesas offers the most versatile microcontroller families in the world for example our RX family offers a many types devices with memory variants from 32K flash/4K RAM to an incredible 8M flash/512K RAM. The RX Family of 32-bit microcontrollers is a feature rich, general purpose MCU covering a wide range of embedded control applications with high speed connectivity, digital signal processing and inverter control.

 

The RX microcontroller family uses a 32-bit enhanced Harvard CISC architecture to achieve very high performance.

Description:: Pin Description Pin arrangement of Renesas microcontroller is shown in figure: f igure:

It is a 20 pin pi n microcontroller. The pin 9 is Vss, ground pin and Vdd, power supply pin. It has three different kinds of interrupt, which are normal interrupt, fast interrupt, high speed interrupt. Normal interrupts store the significant registers on stack by using push and pop instructions. The fast interrupts are automatically store program counter and processor status word in special backup registers, so response time is faster. And high speed interrupts allocate up to four of the general registers for dedicated use by the interrupt to expand speed even further. The internal bus structure gives 5 internal busses to ensure data handling is not slowed down. Instruction fetches occur via a wide 64-bit bus, so that due to the variable length instructions used in CISC architectures.