Microcontroller Basics:
Any electric
appliance that stores, measures, displays information or calculates
comprise of a microcontroller chip inside it. The basic structure of a
microcontroller comprise of:-
- CPU – Microcontrollers brain is named as CPU. CPU is the device which is employed to fetch data, decode it and at the end complete the assigned task successfully. With the help of CPU all the components of microcontroller is connected into a single system. Instruction fetched by the programmable memory is decoded by the CPU.
- Memory – In a microcontroller memory chip works same as microprocessor. Memory chip stores all programs & data. Microcontrollers are built with certain amount of ROM or RAM (EPROM, EEPROM, etc) or flash memory for the storage of program source codes.
- Input/output ports – I/O ports are basically employed to interface or drive different appliances such as- printers, LCD’s, LED’s, etc.
- Serial Ports – These ports give serial interfaces amid microcontroller & various other peripherals such as parallel port.
- Timers – A microcontroller may be in-built with one or more timer or counters. The timers & counters control all counting & timing operations within a microcontroller. Timers are employed to count external pulses. The main operations performed by timers’ are- pulse generations, clock functions, frequency measuring, modulations, making oscillations, etc.
- ADC (Analog to digital converter) – ADC is employed to convert analog signals to digital ones. The input signals need to be analog for ADC. The digital signal production can be employed for different digital applications (such as- measurement gadgets).
- DAC (digital to analog converter) – this converter executes opposite functions that ADC perform. This device is generally employed to supervise analog appliances like- DC motors, etc.
- Interpret Control- This controller is employed for giving delayed control for a working program. The interpret can be internal or external.
- Special Functioning Block – Some special microcontrollers manufactured for special appliances like- space systems, robots, etc, comprise of this special function block. This special block has additional ports so as to carry out some special operations.
Types of Microcontroller:
Microcontrollers
are divided into categories according to their memory, architecture,
bits and instruction sets. So let’s discuss types of microcontrollers:-
Bits:
- 8 bits microcontroller executes logic & arithmetic operations. Examples of 8 bits micro controller is Intel 8031/8051.
- 16 bits microcontroller executes with greater accuracy and performance in contrast to 8-bit. Example of 16 bit microcontroller is Intel 8096.
- 32 bits microcontroller is employed mainly in automatically controlled appliances such as office machines, implantable medical appliances, etc. It requires 32-bit instructions to carry out any logical or arithmetic function.
Memory:
- External Memory Microcontroller – When an embedded structure is built with a microcontroller which does not comprise of all the functioning blocks existing on a chip it is named as external memory microcontroller. For illustration- 8031 microcontroller does not have program memory on the chip.
- Embedded Memory Microcontroller – When an embedded structure is built with a microcontroller which comprise of all the functioning blocks existing on a chip it is named as embedded memory microcontroller. For illustration- 8051 microcontroller has all program & data memory, counters & timers, interrupts, I/O ports and therefore its embedded memory microcontroller.
Instruction Set:
- CISC- CISC means complex instruction set computer, it allows the user to apply 1 instruction as an alternative to many simple instructions.
- RISC- RISC means Reduced Instruction Set Computers. RISC reduces the operation time by shortening the clock cycle per instruction.
Memory Architecture:
- Harvard Memory Architecture Microcontroller
- Princeton Memory Architecture Microcontroller
8051 Microcontroller:
The most universally employed set of microcontrollers come from the 8051 family. 8051 Microcontrollers persist to be an ideal choice for a huge group of hobbyists and experts. In the course of 8051,
the humankind became eyewitness to the most ground-breaking set of
microcontrollers. The original 8051 microcontroller was initially
invented by Intel. The two other members of this 8051 family are-
- 8052 – This microcontroller has 3 timers & 256 bytes of RAM. Additionally it has all the features of the traditional 8051 microcontroller. 8051 microcontroller is a subset of 8052 microcontroller.
- 8031 – This microcontroller is ROM less, other than that it has all the features of a traditional 8051 microcontroller. For execution an external ROM of size 64K bytes can be added to its chip.
8051 microcontroller brings into play 2 different sorts of memory such as- NV-RAM, UV-EPROM and Flash.
8051 Microcontroller Architecture:
8051
microcontroller is an eight bit microcontroller launched in the year
1981 by Intel Corporation. It is available in 40 pin DIP (dual inline
package). It has 4kb of ROM (on-chip programmable space) and 128 bytes
of RAM space which is inbuilt, if desired 64KB of external memory can be
interfaced with the microcontroller. There are four parallel 8 bits
ports which are easily programmable as well as addressable. An on-chip
crystal oscillator is integrated in the microcontroller which has
crystal frequency of 12MHz. In the microcontroller there is a serial
input/output port which has 2 pins. Two timers of 16 bits are also
incorporated in it; these timers can be employed as timer for internal
functioning as well as counter for external functioning. The
microcontroller comprise of 5 interrupt sources namely- Serial Port
Interrupt, Timer Interrupt 1, External Interrupt 0, Timer Interrupt 0,
External Interrupt 1. The programming mode of this micro-controller
includes GPRs (general purpose registers), SFRs (special function
registers) and SPRs (special purpose registers).
PIC Microcontroller:
PIC Microcontroller Architecture:
The architecture of the 8 bit PIC microcontrollers can be categorized as below -
- Base Line Architecture - In the base-line architecture PIC microcontrollers of PIC10F family is included, other than that a fraction of PIC12 & PIC16 families are also included. These gadgets make use of 12 bit program word architecture with six to twenty-eight pin package alternatives. Briefly defined attribute set of baseline architecture allows the most lucrative product solutions. This architecture is perfect for battery enabled gadgets. The PIC10F200 series is another reasonably priced 8 bit flash micro-controller with a 6 pin package.
- Mid Range Architecture - In this midline member of PIC12 & PIC16 families are added that attribute 14 bit program word architecture. The midrange PIC16 gadgets proffer a broad variety of package alternatives (from 8 to 64 package), with low to high levels of peripheral incorporation. This PIC16 appliance attributes a variety of analog, digital & serial peripherals, like- SPI, USART, I2C, USB, LCD & A/D converters. The mid-range PIC16 micro-controllers have suspended controlling ability with an eight level hardware load.
- High Performance Architecture - The high performance architecture included the PIC18 family of appliances. These micro-controllers make use of 16 bit program word architecture along with 18 to 100 pin package alternatives. The PIC18 appliances are high performance micro-controllers with incorporated Analog to Digital converters. All PIC18 micro-controllers integrate a highly developed RISC architecture that supports flash appliances. The PIC18 has improved foundation attributes, 32 level deep load and several inner and exterior interrupts.
Note: List of Top PIC Microcontroller Projects for Engineering Students
AVR Microcontroller:
AVR also
known as Advanced Virtual RISC, is a customized Harvard architecture 8
bit RISC solitary chip micro-controller. It was invented in the year
1966 by Atmel. Harvard architecture signifies that program & data
are amassed in different spaces and are used simultaneously. It was one
of the foremost micro-controller families to employ on-chip flash memory
basically for storing program, as contrasting to one time programmable
EPROM, EEPROM or ROM, utilized by other micro-controllers at the same
time. Flash memory is a non-volatile (constant on power down)
programmable memory.
AVR Microcontroller Architecture:
AVR
microcontrollers’ architecture was developed by Alf-Egil
Bogen and Vegard Wollan. The name AVR is derived from the names of the
architecture developers of the microcontroller. The AT90S8515 was the
foremost micro-controller which was AVR architecture based; on the other
hand the foremost micro-controller to strike the commercial marketplace
was AT90S1200 which was launched in the year 1997.
The SRAM,
Flash and EEPROM all are incorporated on a single chip, thereby
eliminating the requirement of any other external memory in maximum
devices. Several appliances comprise of parallel external bus
alternative, so as to add extra data memory gadgets. Approximately all
appliances, except TinyAVR chips comprise serial interface, which is
used to link large serial Flash & EEPROMs chips.
ARM Microcontroller:
ARM is the
name of a company that designs micro-processors architecture. It is also
engaged in licensing them to the producers who fabricate genuine chips.
In actuality ARM is a 32 bit genuine RISC architecture. It was
initially developed in the year 1980 by Acorn Computers Ltd. This ARM
base microprocessor does not have on-board flash memory. ARM is
particularly designed for micro-controller devices, it is simple to be
trained and make use of, however powerful enough for the most
challenging embedded devices.
ARM Microcontroller Architecture:
The ARM
architecture is a 32 bit RISC processor developed by ARM Ltd. Owing to
its power-saving attributes, ARM central processing units are prevailing
in the mobile electronics marketplace, where less power expenditure is a
vital design aim. ARM architecture comprise of the underneath RISC
elements:-
- Maximum single cycle functioning
- Constant 16×32 bit register file.
- Load or store architecture.
- Preset instruction width of 32 bits so as to simplify pipe-lining and decoding, at minimized code density.
- For misaligned memory access there is no support.
Microcontroller Applications:
Microcontrollers
are intended for embedded devices, in comparison to the
micro-processors which are used in PCs or other all-purpose devices.
Microcontrollers are employed in automatically managed inventions and
appliances like- power tools, implantable medical devices, automobile
engine control systems, , office machines, remote controls appliances,
toys and many more embedded systems. By dipping the size and expenditure
in comparison to a design that make use of a different micro-processor,
I/O devices and memory, micro-controllers formulate it inexpensive to
digitally control more & more appliances and operations. Mixed
signal micro-controllers are general; putting together analog
constituents required controlling non-digital electronic structures.
Application of Microcontroller in Day to Day Life Devices:
- Light sensing & controlling devices
- Temperature sensing and controlling devices
- Fire detection & safety devices
- Industrial instrumentation devices
- Process control devices
Application of Microcontroller in Industrial Control Devices:
- Industrial instrumentation devices
- Process control devices
Application of Microcontroller in Metering & Measurement Devices:
- Volt Meter
- Measuring revolving objects
- Current meter
- Hand-held metering systems
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