/**
 * ECE 315 Assignment 3 - main.c
 * Purpose: Samples ADC0 every 1 second and sends the value to an SPI peripheral.
 */

#include <stdio.h>
#include <string.h>
#include "pico/stdlib.h"
#include "hardware/adc.h"
#include "hardware/spi.h"

#define ADC_PIN 26
#define SPI_PORT spi0
#define PIN_SCK  18
#define PIN_MOSI 19
#define PIN_CS   17

int main() {
  stdio_init_all();

    // Initialize ADC
    adc_init();
    adc_gpio_init(ADC_PIN); // GP26
    adc_select_input(0);    // ADC0

    // Initialize SPI at 0.5 MHz
    spi_init(SPI_PORT, 500 * 1000);
    gpio_set_function(PIN_SCK, GPIO_FUNC_SPI);
    gpio_set_function(PIN_MOSI, GPIO_FUNC_SPI);
    
    // Initialize chip select
    gpio_init(PIN_CS);
    gpio_set_dir(PIN_CS, GPIO_OUT);
    gpio_put(PIN_CS, 1); // High = Deselected

    char msg_buffer[32];

    while (true) {
        // Read from the noise-maker chip
        // 12-bit ADC: 0 to 4095. With 3.3V ref, 1V is roughly 1241
        uint16_t raw_value = adc_read();
        float voltage = raw_value * (3.3f / 4095.0f);

        // Print sampled voltage to main console
        printf("Pico: Sampled Voltage = %.3f V\n", voltage);

        // // Format string for the SPI chip
        // snprintf(msg_buffer, sizeof(msg_buffer), "Value: %.3f V\n", voltage);

        // // Send to my-output-display chip via SPI
        // gpio_put(PIN_CS, 0); // Select chip (Active Low)
        // spi_write_blocking(SPI_PORT, (uint8_t *)msg_buffer, strlen(msg_buffer));
        // gpio_put(PIN_CS, 1); // Deselect chip

        // Wait 1 second before sampling again
        sleep_ms(1000);
    }

    return 0;
}