Classification of PIC 8-bit microcontrollers

Single chip microcomputer STM32L151CCU6

1206RGB (single)

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ)

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

Photocoupler

PIC 8-bit microcontrollers are divided into three main series: Basic, Mid-range, and Advanced. Each series caters to different application needs, offering varying levels of performance, features, and flexibility.

A. Basic Series The Basic Series is known for its affordability and simplicity. It includes models like PIC16C5X, which is ideal for cost-sensitive applications such as household appliances. Another example is the PIC12C5XX, the first 8-pin low-cost microcontroller in the world. Its compact size makes it suitable for applications where space was previously a constraint.

B. Mid-range Series The Mid-range Series is the most versatile of the PIC family. It builds upon the Basic Series with enhanced features while maintaining high compatibility. These devices come in various packages, from 8 pins up to 68 pins, such as the PIC12C6XX. They offer advanced functions like internal ADC, EEPROM memory, comparator outputs, PWM, and communication interfaces like I2C and SPI. This series is well-suited for a wide range of electronic designs, from low-end to mid-range systems.

C. Advanced Series The Advanced Series, including models like PIC17CXX, is designed for high-speed applications. These microcontrollers can perform 8×8 bit binary multiplication in a single instruction cycle (160ns), making them suitable for tasks typically handled by DSPs. They also provide rich I/O capabilities and support for external EPROM and RAM, making them among the highest-performing 8-bit MCUs available. This makes them ideal for more complex, high-end electronic systems.

All three PIC series share high code compatibility, allowing developers to easily transition between models. One of the key advantages of PIC microcontrollers is their reduced instruction set and fast execution speed. Unlike traditional CISC-based microcontrollers, PIC uses a Harvard architecture with a dual-bus structure, enabling simultaneous access to program and data memory, which significantly improves performance.

Dual-Bus Structure In a typical CISC microcontroller, instructions and data are fetched from the same memory space using a single bus. This leads to a bottleneck, as the CPU can only process one at a time. This is known as the von Neumann architecture. In contrast, the PIC series employs a Harvard architecture with two separate buses: one for program instructions and another for data. For example, while the data bus is 8 bits, the instruction bus varies—12-bit for low-end models, 14-bit for mid-range, and 16-bit for high-end models. This allows the microcontroller to fetch an instruction and access data simultaneously, greatly improving efficiency and speed.