PIC16F877-20/PQ

The PIC16F877-20/PQ microcontroller is an 8-bit device with a wide range of applications and features. It has a variety of on-chip peripherals, including a timer, voltage reference, capture/compare/pwm and an external interrupt. The PIC16F877-20/PQ has an internal oscillator with a frequency range of 0.2 to 4 MHz. It also has an external oscillator option with a range of 2 to 20 MHz. The PIC16F877-20/PQ has a memory size of 1K words of program memory and 2K words of RAM. It is available with 20, 28 or 40 pins.

The PIC16F877-20/PQ is a popular choice for embedded applications such as medical devices, vending machines, industrial control, and automotive applications. It is widely used in applications where a cost effective and reliable device is needed. It is also widely used in the hobbyist community due to its low cost and ease of programmability.

The PIC16F877-20/PQ has a wide range of input and output functions which are controlled by the processor. It has three ports, PORTA, PORTB and PORTC, each of which can be programmed for either input or output. It also has a serial peripheral interface (SPI) which can be used to communicate with external devices. The PIC16F877-20/PQ also features an ADC, TIMER0, TIMER1 and TIMER2 which can be used to measure analog input or generate one-shot or continuous timing signals. The PIC16F877-20/PQ also has several built-in functions, like software wake-up, power on reset, low voltage start and ring detect.

The PIC16F877-20/PQ uses a Harvard architecture that is a parallel processor. This means that the PIC16F877-20/PQ has separate memories for instructions and data. The instructions and data can be accessed at the same time, allowing for faster execution of instructions. The PIC16F877-20/PQ is programmed using Assembly language. This language stores instructions and data in the form of bytes (or words) which are processed as 8-bit quantities. The PIC16F877-20/PQ also has a wide range of hardware features, like hardware pulse width modulation, hardware capture, hardware loop indexing, hardware interrupt system and hardware stack.

The working principles of the PIC16F877-20/PQ microcontroller include the following. The processor reads the instruction from the program memory and decodes it. The device then performs operations such as mathematical calculations, read/writes data to memory, or manipulates I/O lines. If the interrupt system is enabled, the processor will be interrupted by external events. The microcontroller is then able to access the data from the interrupt vector table and then proceed with the instruction required to handle the interrupt. The PIC16F877-20/PQ has a Clock-Locking (CLKL) feature that allows the user to lock the processor clock on a certain frequency by manually adjusting a clock frequency selection bit. This feature can be used to prevent the device from running too fast and thus, reduce power consumption.

In conclusion, the PIC16F877-20/PQ microcontroller is a highly capable, cost effective, and reliable device that is ideal for use in embedded applications. Its features, such as its on-chip peripherals, wide range of input/output functions, Harvard architecture, and CLKL feature, make it an ideal choice for hobbyists as well as industrial automation applications.