Logic analyzer for signal debugging in Embedded C

Introduction

A logic analyzer helps you watch digital signals change over time. It shows when signals go high or low so you can find problems in your circuits.

You want to check if a button press changes a signal correctly.

You need to see the timing of signals between microcontroller pins.

You want to debug communication signals like SPI or I2C.

You want to record signal changes to find glitches or errors.

Syntax

Embedded C

void capture_signals(void) {
    // Setup pins as inputs
    // Start timer or interrupt to sample pins
    // Store pin states in buffer
    // Analyze or print results
}

This is a simple function outline to capture digital signals.

You usually sample pins repeatedly and save their states for later analysis.

Examples

This example reads one pin 100 times with 10 microseconds delay between samples.

Embedded C

void capture_signals(void) {
    for (int i = 0; i < 100; i++) {
        buffer[i] = (PINB & 0x01); // Read pin B0
        _delay_us(10); // Wait 10 microseconds
    }
}

This reads 4 pins at once, storing their states in a buffer.

Embedded C

void capture_signals(void) {
    for (int i = 0; i < 50; i++) {
        buffer[i] = (PIND & 0x0F); // Read pins D0-D3
        _delay_us(20);
    }
}

Sample Program

This program reads the state of pin B0 ten times, waiting 100 milliseconds between each read. It stores the results in a buffer and then prints each sample.

Embedded C

#include <avr/io.h>
#include <util/delay.h>
#include <stdio.h>

#define SAMPLE_COUNT 10
uint8_t buffer[SAMPLE_COUNT];

void capture_signals(void) {
    for (int i = 0; i < SAMPLE_COUNT; i++) {
        buffer[i] = (PINB & 0x01); // Read pin B0
        _delay_ms(100); // Wait 100 milliseconds
    }
}

int main(void) {
    DDRB &= ~(1 << DDB0); // Set pin B0 as input
    capture_signals();

    for (int i = 0; i < SAMPLE_COUNT; i++) {
        printf("Sample %d: %d\n", i, buffer[i]);
    }
    return 0;
}

Important Notes

Make sure the input pins are configured correctly as inputs.

Use delays to control how often you sample signals.

Buffers help store many samples for later review.

Summary

A logic analyzer captures digital signal changes over time.

Use loops and delays to sample pins repeatedly.

Store samples in a buffer to analyze or print later.