AD5200 example

ad5200.c

#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/spi_master.h"
#include "esp_log.h"
#include "esp_err.h"

static const char *TAG = "AD5200";

#define PIN_NUM_MOSI  23
#define PIN_NUM_CLK   18
#define PIN_NUM_CS     5
#define SPI_HOST       VSPI_HOST

// If you don’t get sane behavior, the first thing to try is SPI mode 1.
#define AD5200_SPI_MODE 0

static spi_device_handle_t g_ad5200;

static esp_err_t ad5200_write(uint8_t code)
{
   spi_transaction_t t;
   memset(&t, 0, sizeof(t));

   t.length = 8;           // bits
   t.tx_buffer = &code;

   return spi_device_transmit(g_ad5200, &t);
}

static esp_err_t ad5200_init(void)
{
   spi_bus_config_t buscfg = {
      .mosi_io_num = PIN_NUM_MOSI,
      .miso_io_num = -1,          // AD5200 is write-only
      .sclk_io_num = PIN_NUM_CLK,
      .quadwp_io_num = -1,
      .quadhd_io_num = -1,
      .max_transfer_sz = 4,
   };

   spi_device_interface_config_t devcfg = {
      .clock_speed_hz = 1 * 1000 * 1000, // 1 MHz to start
      .mode = AD5200_SPI_MODE,
      .spics_io_num = PIN_NUM_CS,
      .queue_size = 1,
   };

   ESP_ERROR_CHECK(spi_bus_initialize(SPI_HOST, &buscfg, SPI_DMA_CH_AUTO));
   ESP_ERROR_CHECK(spi_bus_add_device(SPI_HOST, &devcfg, &g_ad5200));
   ESP_LOGI(TAG, "SPI ready");
   return ESP_OK;
}

void app_main(void)
{
   ESP_ERROR_CHECK(ad5200_init());

   // Example: set midscale (0x80), then ramp.
   ESP_ERROR_CHECK(ad5200_write(0x80));
   vTaskDelay(pdMS_TO_TICKS(300));

   for (int v = 0; v <= 255; v += 32) {
      ESP_ERROR_CHECK(ad5200_write((uint8_t)v));
      vTaskDelay(pdMS_TO_TICKS(200));
   }
}