Microcontrollers are placed an important role in the electronics industry. It brings more efficient, low-power consumption and high performance to embedded systems. This article is for Microchip PIC Microcontroller.
PIC initially stands for Peripheral Interface Controller. It was originally developed by General Instruments in 1975, to improve the overall performance of the system by offloading the I/O tasks from the CPU. It currently has an expanded scope. The General Instruments used the acronyms Programmable Interface Controller and Programmable Intelligent Computer for the initial PICs (PIC1640 and PIC1650).
In 1985, General Instruments converted their Microelectronics Division to Microchip Technology. Since 1998, Microchip developed new high-performance microcontrollers with new complex architecture and enhanced in-built peripherals.
PIC12F675-I/P
Microchip PIC Microcontrollers
Microchip introduce 8-bit, 16-bit, and 32-bit PIC microcontrollers to simplify the design process. It provides solutions for a wide variety of performance and functional needs of electronic applications such as consumer electronics, industrial, medical, automotive, etc.
All PIC MCUs consist of ROM, RAM, CPU, timers, and counters that support protocols for interfacing purposes. Besides, FLASH memory, I/O ports, EEPROM, UART, SSP, ADC, and PSP are also integrated.
The Types of PIC Microcontrollers
There are four categories of 8-bit PIC Microcontrollers based on their internal architecture. Base Line PIC, Mid-range PIC, Enhance Mid-range PIC, and PIC18.
Base Line PICs work on 12-bit instruction architecture. It is the least complex PIC microcontroller which is cost-effective and compact, with 6 to 40 pin packaging.
Mid-range PICs are based on 14-bit instruction architecture. The working speed is up to 20MHz. It is available with different peripherals and communication protocols, with 8 to 64 pin packaging.
Enhanced Mid-range PICs are enhanced versions of Mid-range core. It provides upgraded functions and includes multiple peripherals and supports protocols such as USART, SPI, I2C, etc.
PIC18 is based on 16-bit instruction architecture incorporating advanced RISC architecture.
Based on different applications and the requirement of the projects, selecting the right PIC is one of the important steps. There is plenty of part numbers in the market. Knowing which type and size of PIC are correct to settle on the electronic circuit will easy for you to communicate with PCB assembly partners.
What should be taken into consideration when selecting a PIC?
Before development, the designer should consider the programming software to deploy. As the PIC microcontrollers need programming for specific applications. In most instances, a typical programming language usually features the embedded C language. The architecture is something you should understand when designing and programming a PIC microcontroller.
PIC microcontrollers are based on an advanced RISC architecture. RISC stands for Reduced Instruction Set Computing. In this architecture, the instruction set of the hardware is reduced, thereby increasing the execution rate (speed) of the system.
CPU (Central Processing Unit)
CPU is the heart of the microcontroller. It has a CU, AC, ALU, accumulator, MU, etc. CU is a control unit that controls everything connected to the CPU. ALU is an arithmetic logic unit that carries out arithmetic operations besides undertaking logical decisions. MU is a memory unit that stores instructions.
Memory
The memory organization module consists of ROM, RAM, and STACK. The memory size is one of the important factors that you should take into consideration. ROM stores data permanently, while the RAM stores data momentarily in its registers. STACK stores and executes the information from the completion of the interrupt execution.
The types of memory include Program Memory, RAM, and EEPROM. The Program Memory will hold the program itself and it is usually 1 to 32K Bytes.
RAM is for temporarily storing variables and parameter values. It will be blanked each time the power is off. It is usually 1K Byte, but it is able to have up to 32K Bytes of RAM in 32-bit systems.
The size of EEPROM is up to 4K. It is the memory that reads and writes using a specific program flow. The value it is stored will keep even if the PIC is out of power. EEPROM allows for the programming of the ROM numerous times. Flash memory is also PROM so that it can write, read, and erase programs multiple times.
I/O
The pin count of PIC is also the factor you should consider. I/O ports allow for connections to internal or external hardware. There are tiny 4 I/O ports and some titans with 85 I/O ports. Among 16 I/O (18 pins) and 38 I/O (40 pins) are the most commonly used.
Frequency
The fastest the clock, the faster the program flows. However, it is not mean the fastest is the better. A standard 20Mhz is usually enough for an amateur developer. Some PICs are equipped with an internal oscillator, which allows them to work with no external crystal or other oscillators, and also saves space on the PCB and of course, it can save power.
It is critical to understand PIC Microcontrollers before designing electronic circuits. The MCUs are continual upgrade with more enhanced functions. Having insights into the intricacies of the PIC microcontrollers to stay ahead of your projects. And it also helps to get higher performance with cost-effectiveness.