/*
 * File: main.c
 * Author: Isaac Tong
 * Course: ECE 315
 * Assignment: Assignment 3
 *
 * Description:
 * Samples analog noise generated by the noise-maker custom chip
 * once per second using the Raspberry Pi Pico ADC. The sampled
 * value is printed locally and transmitted over SPI to a custom
 * SPI display chip that prints the received data.
 */
#include <stdio.h>
#include "pico/stdlib.h"
#include <string.h>
#include "hardware/adc.h"
#include "hardware/spi.h"
#include "hardware/gpio.h"
#define SPI_PORT spi0
#define PIN_MISO 7
#define PIN_CS   5
#define PIN_SCK  6

int main() {

  stdio_init_all();

  // ADC setup
  adc_init();
  adc_gpio_init(26);   // GP26 = ADC0
  adc_select_input(0);

  // SPI setup
  spi_init(SPI_PORT, 100000);
  gpio_set_function(PIN_MISO, GPIO_FUNC_SPI);
  gpio_set_function(PIN_SCK, GPIO_FUNC_SPI);
  spi_set_format(SPI_PORT, 8, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST);

  gpio_init(PIN_CS);
  gpio_set_dir(PIN_CS, GPIO_OUT);
  gpio_put(PIN_CS, 1);

  char msg[64];

  while (true) {
    uint16_t raw = adc_read();
    float voltage = raw * 3.3f / 4095.0f;//converts into real voltage value
    //sends message
    printf("ADC Voltage: %.3f V\n", voltage);
    sprintf(msg, "Voltage: %.3f\n", voltage);

    gpio_put(PIN_CS, 0);
    spi_write_blocking(SPI_PORT, (uint8_t *)msg, strlen(msg));
    gpio_put(PIN_CS, 1);

    sleep_ms(1000);
  }
}