#include <driver/spi_master.h>
void test_spi_task(void *ignore) {
   ESP_LOGD(tag, ">> test_spi_task");

   spi_bus_config_t bus_config;
   bus_config.sclk_io_num   = clkPin; // CLK
   bus_config.mosi_io_num   = mosiPin; // MOSI
   bus_config.miso_io_num   = misoPin; // MISO
   bus_config.quadwp_io_num = -1; // Not used
   bus_config.quadhd_io_num = -1; // Not used
   ESP_LOGI(tag, "... Initializing bus.");
   ESP_ERROR_CHECK(spi_bus_initialize(HSPI_HOST, &bus_config, 1));


   spi_device_handle_t handle;
   spi_device_interface_config_t dev_config;
   dev_config.address_bits     = 0;
   dev_config.command_bits     = 0;
   dev_config.dummy_bits       = 0;
   dev_config.mode             = 0;
   dev_config.duty_cycle_pos   = 0;
   dev_config.cs_ena_posttrans = 0;
   dev_config.cs_ena_pretrans  = 0;
   dev_config.clock_speed_hz   = 10000;
   dev_config.spics_io_num     = csPin;
   dev_config.flags            = 0;
   dev_config.queue_size       = 1;
   dev_config.pre_cb           = NULL;
   dev_config.post_cb          = NULL;
   ESP_LOGI(tag, "... Adding device bus.");
   ESP_ERROR_CHECK(spi_bus_add_device(HSPI_HOST, &dev_config, &handle));


   char data[3];
   spi_transaction_t trans_desc;
   trans_desc.address   = 0;
   trans_desc.command   = 0;
   trans_desc.flags     = 0;
   trans_desc.length    = 3 * 8;
   trans_desc.rxlength  = 0;
   trans_desc.tx_buffer = data;
   trans_desc.rx_buffer = data;

   data[0] = 0x12;
   data[1] = 0x34;
   data[2] = 0x56;

   ESP_LOGI(tag, "... Transmitting.");
   ESP_ERROR_CHECK(spi_device_transmit(handle, &trans_desc));

   ESP_LOGI(tag, "... Removing device.");
   ESP_ERROR_CHECK(spi_bus_remove_device(handle));

   ESP_LOGI(tag, "... Freeing bus.");
   ESP_ERROR_CHECK(spi_bus_free(HSPI_HOST));

   ESP_LOGD(tag, "<< test_spi_task");
   vTaskDelete(NULL);
}