//=================================================================================//

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

//=================================================================================//

#define BUF_LEN 128

//=================================================================================//

void printbuf (uint8_t buf [], size_t len) {
  int i;
  for (i = 0; i < len; ++i) {
    if (i % 16 == 15)
      printf ("%02x\n", buf [i]);
    else
      printf ("%02x ", buf [i]);
  }
  // append trailing newline if there isn't one
  if (i % 16) {
    putchar ('\n');
  }
}

//=================================================================================//

int main() {
  // Enable USB serial so we can print
  stdio_init_all();
  sleep_ms (2 * 1000);
  printf ("SPI Central Example\n");

  // Enable SPI0 at 1 MHz
  spi_init (spi_default, 1 * 1000000);

  // Assign SPI functions to the default SPI pins
  gpio_set_function (PICO_DEFAULT_SPI_RX_PIN, GPIO_FUNC_SPI);
  gpio_set_function (PICO_DEFAULT_SPI_SCK_PIN, GPIO_FUNC_SPI);
  gpio_set_function (PICO_DEFAULT_SPI_TX_PIN, GPIO_FUNC_SPI);
  gpio_set_function (PICO_DEFAULT_SPI_CSN_PIN, GPIO_FUNC_SPI);

  // // Make the SPI pins available to picotool
  // bi_decl ( bi_4pins_with_func (
  //     PICO_DEFAULT_SPI_RX_PIN,
  //     PICO_DEFAULT_SPI_TX_PIN,
  //     PICO_DEFAULT_SPI_SCK_PIN,
  //     PICO_DEFAULT_SPI_CSN_PIN,
  //     GPIO_FUNC_SPI
  //   )
  // );

  // We need two buffers, one for the data to send, and one for the data to receive.
  uint8_t out_buf [BUF_LEN], in_buf [BUF_LEN];

  // Initialize the buffers to 0.
  for (u_int8_t i = 0; i < BUF_LEN; ++i) {
    out_buf [i] = 0;
    in_buf [i] = 0;
  }

  for (uint8_t i = 0; ; ++i) {
    printf ("Sending data %d to SPI Peripheral\n", i);
    out_buf [0] = i;
    // Write the output buffer to COPI, and at the same time read from CIPO to the input buffer.
    spi_write_read_blocking (spi_default, out_buf, in_buf, 1);

    // Sleep for some seconds so you get a chance to read the output.
    sleep_ms (2 * 1000);
  }
}

//=================================================================================//