main.c

#include <stdio.h>
#include "esp_system.h"
#include "esp_event.h"
#include "driver/spi_master.h"


#define TEST_MISO_PIN 19
#define TEST_MOSI_PIN 18
#define TEST_SCLK_PIN 5
#define TEST_CS1_PIN 27
#define TEST_CS2_PIN 32


void app_main(void)
{
	static spi_device_handle_t spi1;
	static spi_device_handle_t spi2;


	// Initialize SPI bus
	{
		spi_bus_config_t buscfg = {
			.miso_io_num = TEST_MISO_PIN,
			.mosi_io_num = TEST_MOSI_PIN,
			.sclk_io_num = TEST_SCLK_PIN,
			.quadwp_io_num = -1,
			.quadhd_io_num = -1
		};

		ESP_ERROR_CHECK(spi_bus_initialize(VSPI_HOST, &buscfg, 0));
	}

	// Setup SPI device 1 (half-duplex)
	{
		spi_device_interface_config_t devcfg = {
			.clock_speed_hz = 1*100*1000,
			.mode = 0,
			.queue_size = 1,
			.flags = SPI_DEVICE_HALFDUPLEX,
			.spics_io_num = TEST_CS1_PIN
		};

		ESP_ERROR_CHECK(spi_bus_add_device(VSPI_HOST, &devcfg, &spi1));
	}

	// Setup SPI device 2 (full-duplex, 8 addr. bits)
	{
		spi_device_interface_config_t devcfg = {
			.clock_speed_hz = 1*100*1000,
			.mode = 0,
			.queue_size = 1,
			.flags = 0,
			.command_bits = 0,
			.address_bits = 8,
			.spics_io_num = TEST_CS2_PIN
		};

		ESP_ERROR_CHECK(spi_bus_add_device(VSPI_HOST, &devcfg, &spi2));
	}


	printf("Starting in 2s...\n");
	sleep(2);

	// Do a dummy transfer on device 1
	{
		uint8_t cmd = 0x3A;
		spi_transaction_t t = {
			.length = 8,
			.tx_buffer = &cmd
		};
		spi_device_transmit(spi1, &t);
	}

	// Do a 16-bit full-duplex transfer (+8 addr. bits) on device 2
	{
		spi_transaction_t t = {
			.length = 16,
			.rxlength = 16,
			.flags = SPI_TRANS_USE_RXDATA | SPI_TRANS_USE_TXDATA
		};
		uint8_t addr = 0x00;
		t.addr = addr | 0x80;
		t.tx_data[0] = (addr+1) | 0x80;
		t.tx_data[1] = 0x00;
		t.tx_data[2] = 0x13;
		t.tx_data[3] = 0x37;
		ESP_ERROR_CHECK(spi_device_transmit(spi2, &t));
	}
}