PIC Microcontrollers: How They Work and How to Use Them

PIC Microcontrollers: An Introduction to Microelectronics

If you are interested in learning about microelectronics, you may have heard of PIC microcontrollers. These are small, powerful, and versatile devices that can be used for a variety of applications, such as robotics, automation, sensors, communication, and more. But what are PIC microcontrollers exactly? How do they work? And how can you use them in your own projects? In this article, we will answer these questions and more, based on the book "PIC Microcontrollers, Third Edition: An Introduction to Microelectronics.pdf" by Martin Bates.

PIC Microcontrollers, Third Edition: An Introduction To Microelectronics.pdf

What are PIC microcontrollers?

PIC is an abbreviation used for Peripheral Interface Controller. PIC microcontrollers are the smallest microcontrollers in the world and are programmed to execute large number of operations. These were initially designed to support PDP (programmed data processor) computers, for controlling the peripheral devices. [1]

PIC microcontrollers are made by Microchip Technology, a company that was formed in 1985 by spinning off the chip division of General Instrument. The name PIC initially referred to Peripheral Interface Controller, but is currently expanded as Programmable Intelligent Computer. [2]

PIC microcontrollers have some features and advantages that make them popular among hobbyists, students, and professionals. Some of these are:

• PIC microcontrollers have a simple and easy-to-use instruction set that can be learned quickly.

• PIC microcontrollers have a low cost and high performance ratio, making them affordable and efficient.

• PIC microcontrollers have a wide range of models with different memory sizes, pin counts, clock speeds, and peripheral modules.

• PIC microcontrollers have a high level of integration, meaning they have built-in memory, timers, counters, I/O ports, ADCs, DACs, UARTs, SPIs, CANs, USBs, and more.

• PIC microcontrollers have a low power consumption and high reliability, making them suitable for battery-operated and harsh environments.

PIC microcontrollers can be used for a variety of applications and examples. Some of these are:

• PIC microcontrollers can be used for sensor node applications, such as temperature monitoring, humidity sensing, light detection, etc.

• PIC microcontrollers can be used for real-time control applications, such as motor control, servo control, PWM generation, etc.

• PIC microcontrollers can be used for connected applications, such as wireless communication, IoT devices, RFID readers, etc.

• PIC microcontrollers can be used for embedded systems applications, such as calculators, alarm clocks, digital thermometers, etc.

• PIC microcontrollers can be used for educational purposes, such as learning about electronics, programming, logic design, etc.

How do PIC microcontrollers work?

To understand how PIC microcontrollers work, we need to look at their architecture and components. The architecture of a PIC microcontroller consists of three main parts: the CPU (central processing unit), the memory (program memory and data memory), and the peripherals (input/output ports and modules). [3]

The CPU is the brain of the PIC microcontroller. It executes the instructions stored in the program memory and performs arithmetic and logic operations on the data stored in the data memory. The CPU has a set of registers, such as the W register (working register), the PC (program counter), the STATUS register (status flags), and the FSR (file select register). The CPU also has a stack, which is used to store the return addresses of subroutines and interrupts. [3]

The memory is the storage of the PIC microcontroller. It consists of two types: the program memory and the data memory. The program memory is where the code or instructions are stored. It can be ROM (read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), or flash memory. The data memory is where the variables or data are stored. It can be RAM (random access memory) or EEPROM. The data memory is divided into two banks: bank 0 and bank 1. Each bank has 128 bytes of addressable space. [3]

The peripherals are the interface of the PIC microcontroller. They consist of input/output ports and modules. The input/output ports are used to connect the PIC microcontroller to external devices, such as LEDs, switches, sensors, etc. The input/output ports can be configured as digital or analog inputs or outputs. The modules are used to provide additional functionality to the PIC microcontroller, such as timers, counters, ADCs (analog-to-digital converters), DACs (digital-to-analog converters), UARTs (universal asynchronous receiver/transmitters), SPIs (serial peripheral interfaces), CANs (controller area networks), USBs (universal serial buses), and more. The modules can be enabled or disabled by setting or clearing some bits in some special registers, such as TRIS (tri-state), PORT (port latch), ADCON (analog-to-digital control), TXSTA (transmit status and control), etc. [3]

To program a PIC microcontroller, we need to use an instruction set and a programming language. The instruction set is a set of commands that the CPU can understand and execute. The instruction set varies by model of PIC microcontroller, and may be 12-bit, 14-bit, 16-bit, or 24-bit long. The instruction set also varies by complexity and functionality, with more powerful chips adding instructions for digital signal processing functions. [2]

The programming language is a set of symbols and rules that we use to write the code or instructions for the PIC microcontroller. The programming language can be low-level or high-level. A low-level programming language is closer to the machine language and uses mnemonics to represent the instructions, such as MOVF, ADDWF, BTFSS, etc. A low-level programming language is also called assembly language. A high-level programming language is closer to the human language and uses keywords and syntax to represent the instructions, such as if, while, for, etc. A high-level programming language is also called C language or BASIC language. [3]

To develop a PIC microcontroller project, we need some tools and software. Some of these are:

• A PIC microcontroller chip, which is the main component of the project.

• A programmer device, which is used to transfer the code from the computer to the PIC microcontroller chip.

• A development board or a breadboard, which is used to connect the PIC microcontroller chip to other components, such as LEDs, switches, sensors, etc.

• A power supply or a battery, which is used to provide power to the PIC microcontroller chip and other components.

• An editor software, which is used to write and edit the code for the PIC microcontroller project.

• A compiler software, which is used to convert the code from a high-level programming language to a low-level programming language.

• An assembler software, which is used to convert the code from a low-level programming language to a machine language.

• A simulator software, which is used to test and debug the code for the PIC microcontroller project without using a physical device.

How to use PIC microcontrollers in projects?

To use PIC microcontrollers in projects, we need to follow some steps. Some of these are:

Choosing the right PIC microcontroller for your project

The first step is to choose the right PIC microcontroller for your project. This depends on several factors, such as:

• The complexity and functionality of your project.

• The memory size and type that you need for your project.

• The number and type of input/output ports and modules that you need for your project.

• The clock speed and power consumption that you need for your project.

PIC microcontroller for your project.

Some examples of PIC microcontroller models are:

Model

Memory Size

Pin Count

Clock Speed

Peripherals

PIC12F675

1.75 KB flash, 64 bytes RAM, 128 bytes EEPROM

8 pins

20 MHz

4 I/O pins, ADC, comparator, timer, PWM

PIC16F877A

14 KB flash, 368 bytes RAM, 256 bytes EEPROM

40 pins

20 MHz

33 I/O pins, ADC, UART, SPI, I2C, CCP, timer, watchdog

PIC18F4550

32 KB flash, 2 KB RAM, 256 bytes EEPROM

40 pins

48 MHz

35 I/O pins, ADC, UART, SPI, I2C, CCP, timer, watchdog, USB

PIC24FJ64GA002

64 KB flash, 8 KB RAM

28 pins

32 MHz

16 I/O pins, ADC, UART, SPI, I2C, timer, watchdog, DMA

PIC32MX795F512L

512 KB flash, 128 KB RAM

100 pins

80 MHz

85 I/O pins, ADC, DAC, UART, SPI, I2C, CAN, USB OTG , Ethernet MAC , timer , watchdog , DMA , PMP , RTCC , CTMU

Designing and prototyping with PIC microcontrollers

The second step is to design and prototype with PIC microcontrollers. This involves:

• Drawing a schematic diagram of your project circuit using a software tool or a paper and pencil.

• Selecting the components that you need for your project circuit based on the schematic diagram.

• Breadboarding your project circuit using a breadboard and jumper wires to connect the components.

• Soldering your project circuit using a soldering iron and solder to make permanent connections between the components.

Testing and debugging with PIC microcontrollers

The third step is to test and debug with PIC microcontrollers. This involves:

• Writing the code for your project using an editor software and a programming language.

• Compiling and assembling your code using a compiler software and an assembler software.

• Loading your code into the PIC microcontroller chip using a programmer device and a software tool.

• Running your code on the PIC microcontroller chip and observing the output on the external devices.

• Finding and fixing any errors or bugs in your code or circuit using a simulator software or a debugger device.

What are the challenges and opportunities for PIC microcontrollers?

PIC microcontrollers are not perfect devices. They have some limitations and drawbacks that may affect their performance and suitability for some projects. Some of these are:

• PIC microcontrollers have a limited memory size and type that may not be enough for some complex or large projects.

• PIC microcontrollers have a limited number and type of input/output ports and modules that may not be compatible with some external devices or protocols.

• PIC microcontrollers have a limited clock speed and power consumption that may not be optimal for some high-speed or low-power projects.

PIC microcontrollers also have some future trends and innovations that may improve their capabilities and applications. Some of these are:

• PIC microcontrollers may have more memory size and type that may allow them to store more code and data.

• PIC microcontrollers may have more input/output ports and modules that may enable them to interface with more external devices or protocols.

• PIC microcontrollers may have higher clock speed and lower power consumption that may enhance their performance and efficiency.

Resources and references for learning more about PIC microcontrollers

If you want to learn more about PIC microcontrollers, you can use some resources and references that may provide you with more information and guidance. Some of these are:

• The book "PIC Microcontrollers, Third Edition: An Introduction to Microelectronics.pdf" by Martin Bates, which is the main source of this article.

• The website of Microchip Technology, which is the manufacturer of PIC microcontrollers and provides datasheets, manuals, tutorials, software, and support.

• The website of Best Microcontroller Projects, which is a source of PIC microcontroller projects and tutorials.

• The website of RayMing, which is a source of PIC microcontroller PCB design and manufacturing.

• The website of Electronics Desk, which is a source of PIC microcontroller basics and concepts.

Conclusion

PIC microcontrollers are small, powerful, and versatile devices that can be used for a variety of applications, such as robotics, automation, sensors, communication, and more. They have some features and advantages that make them popular among hobbyists, students, and professionals. They also have some limitations and drawbacks that may affect their performance and suitability for some projects. They also have some future trends and innovations that may improve their capabilities and applications. To use PIC microcontrollers in projects, we need to choose the right model, design and prototype the circuit, write and load the code, test and debug the project, and learn more from the resources and references.

FAQs

Here are some frequently asked questions about PIC microcontrollers:

• What does PIC stand for?

PIC stands for Peripheral Interface Controller or Programmable Intelligent Computer.

• Who makes PIC microcontrollers?

PIC microcontrollers are made by Microchip Technology.

• How many types of PIC microcontrollers are there?

There are four types of PIC microcontrollers: 8-bit, 16-bit, 24-bit, and 32-bit.

• How do I program a PIC microcontroller?

You can program a PIC microcontroller using a low-level or a high-level programming language, such as assembly or C.

• How do I connect a PIC microcontroller to a computer?

You can connect a PIC microcontroller to a computer using a programmer device and a software tool.

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