Parallel processing is a technique used to execute multiple tasks simultaneously, thereby improving the efficiency and performance of computing systems. In general computing, this is often achieved using multi-core processors and threading. However, in the microchip environment, particularly in embedded systems, the concept of parallel processing can be adapted using techniques such as interrupt-driven programming, direct memory access (DMA), and utilizing multiple microcontroller units (MCUs).

This article will explore how to implement parallel processing in microchip environments, focusing on practical examples and techniques that can be applied to enhance the performance of embedded systems.

Examples:

1. Using Interrupts for Parallel Processing:

Interrupts allow a microcontroller to respond to an event immediately, pausing the main program flow to execute an interrupt service routine (ISR). This can be used to handle multiple tasks in parallel.

#include <avr/io.h>
#include <avr/interrupt.h>

ISR(TIMER1_COMPA_vect) {
    // Code to execute when Timer1 compare match occurs
}

ISR(USART_RX_vect) {
    // Code to execute when UART data is received
}

int main(void) {
    // Configure Timer1
    TCCR1B |= (1 << WGM12); // CTC mode
    TIMSK1 |= (1 << OCIE1A); // Enable compare match interrupt
    sei(); // Enable global interrupts

    // Configure UART
    UCSR0B |= (1 << RXCIE0); // Enable RX complete interrupt
    sei(); // Enable global interrupts

    while (1) {
        // Main program loop
    }
}

2. Using DMA for Parallel Data Transfer:

Direct Memory Access (DMA) allows peripherals to transfer data to/from memory without involving the CPU, enabling parallel data processing.

#include <xc.h>

// DMA configuration for data transfer
void DMA_Init(void) {
    DMA0CON = 0x2001; // Continuous, peripheral indirect, post-increment
    DMA0REQ = 0x0013; // Select UART1 RX as DMA request source
    DMA0STA = __builtin_dmaoffset(&rxBuffer); // Set start address of DMA RAM
    DMA0CNT = 7; // Number of DMA requests
    DMA0PAD = (volatile unsigned int) &U1RXREG; // Peripheral address
    DMA0CONbits.CHEN = 1; // Enable DMA channel
}

int main(void) {
    DMA_Init(); // Initialize DMA

    while (1) {
        // Main program loop
    }
}

3. Using Multiple MCUs for Parallel Processing:

In some cases, using multiple microcontrollers can achieve parallel processing by distributing tasks among them.

// MCU1 - Task1
#include <xc.h>

void Task1_Init(void) {
    // Initialize peripherals for Task1
}

void Task1_Run(void) {
    // Code for Task1
}

int main(void) {
    Task1_Init();

    while (1) {
        Task1_Run();
    }
}

// MCU2 - Task2
#include <xc.h>

void Task2_Init(void) {
    // Initialize peripherals for Task2
}

void Task2_Run(void) {
    // Code for Task2
}

int main(void) {
    Task2_Init();

    while (1) {
        Task2_Run();
    }
}