esp-idf/examples/peripherals/i2c/main/i2c_example_main.c

/* i2c - Example

   For other examples please check:
   https://github.com/espressif/esp-idf/tree/master/examples

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
#include <stdio.h>
#include "driver/i2c.h"

/**
 * TEST CODE BRIEF
 *
 * This example will show you how to use I2C module by running two tasks on i2c bus:
 *
 * - read external i2c sensor, here we use a BH1750 light sensor(GY-30 module) for instance.
 * - Use one I2C port(master mode) to read or write the other I2C port(slave mode) on one ESP32 chip.
 *
 * Pin assignment:
 *
 * - slave :
 *    GPIO25 is assigned as the data signal of i2c slave port
 *    GPIO26 is assigned as the clock signal of i2c slave port
 * - master:
 *    GPIO18 is assigned as the data signal of i2c master port
 *    GPIO19 is assigned as the clock signal of i2c master port
 *
 * Connection:
 *
 * - connect GPIO18 with GPIO25
 * - connect GPIO19 with GPIO26
 * - connect sda/scl of sensor with GPIO18/GPIO19
 * - no need to add external pull-up resistors, driver will enable internal pull-up resistors.
 *
 * Test items:
 *
 * - read the sensor data, if connected.
 * - i2c master(ESP32) will write data to i2c slave(ESP32).
 * - i2c master(ESP32) will read data from i2c slave(ESP32).
 */

#define DATA_LENGTH          512  /*!<Data buffer length for test buffer*/
#define RW_TEST_LENGTH       129  /*!<Data length for r/w test, any value from 0-DATA_LENGTH*/
#define DELAY_TIME_BETWEEN_ITEMS_MS   1234 /*!< delay time between different test items */

#define I2C_EXAMPLE_SLAVE_SCL_IO     26    /*!<gpio number for i2c slave clock  */
#define I2C_EXAMPLE_SLAVE_SDA_IO     25    /*!<gpio number for i2c slave data */
#define I2C_EXAMPLE_SLAVE_NUM I2C_NUM_0    /*!<I2C port number for slave dev */
#define I2C_EXAMPLE_SLAVE_TX_BUF_LEN  (2*DATA_LENGTH) /*!<I2C slave tx buffer size */
#define I2C_EXAMPLE_SLAVE_RX_BUF_LEN  (2*DATA_LENGTH) /*!<I2C slave rx buffer size */

#define I2C_EXAMPLE_MASTER_SCL_IO    19    /*!< gpio number for I2C master clock */
#define I2C_EXAMPLE_MASTER_SDA_IO    18    /*!< gpio number for I2C master data  */
#define I2C_EXAMPLE_MASTER_NUM I2C_NUM_1   /*!< I2C port number for master dev */
#define I2C_EXAMPLE_MASTER_TX_BUF_DISABLE   0   /*!< I2C master do not need buffer */
#define I2C_EXAMPLE_MASTER_RX_BUF_DISABLE   0   /*!< I2C master do not need buffer */
#define I2C_EXAMPLE_MASTER_FREQ_HZ    100000     /*!< I2C master clock frequency */

#define BH1750_SENSOR_ADDR  0x23    /*!< slave address for BH1750 sensor */
#define BH1750_CMD_START    0x23    /*!< Command to set measure mode */
#define ESP_SLAVE_ADDR 0x28         /*!< ESP32 slave address, you can set any 7bit value */
#define WRITE_BIT  I2C_MASTER_WRITE /*!< I2C master write */
#define READ_BIT   I2C_MASTER_READ  /*!< I2C master read */
#define ACK_CHECK_EN   0x1     /*!< I2C master will check ack from slave*/
#define ACK_CHECK_DIS  0x0     /*!< I2C master will not check ack from slave */
#define ACK_VAL    0x0         /*!< I2C ack value */
#define NACK_VAL   0x1         /*!< I2C nack value */

xSemaphoreHandle print_mux;

/**
 * @brief test code to read esp-i2c-slave
 *        We need to fill the buffer of esp slave device, then master can read them out.
 *
 * _______________________________________________________________________________________
 * | start | slave_addr + rd_bit +ack | read n-1 bytes + ack | read 1 byte + nack | stop |
 * --------|--------------------------|----------------------|--------------------|------|
 *
 */
static esp_err_t i2c_example_master_read_slave(i2c_port_t i2c_num, uint8_t* data_rd, size_t size)
{
    if (size == 0) {
        return ESP_OK;
    }
    i2c_cmd_handle_t cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, ( ESP_SLAVE_ADDR << 1 ) | READ_BIT, ACK_CHECK_EN);
    if (size > 1) {
        i2c_master_read(cmd, data_rd, size - 1, ACK_VAL);
    }
    i2c_master_read_byte(cmd, data_rd + size - 1, NACK_VAL);
    i2c_master_stop(cmd);
    esp_err_t ret = i2c_master_cmd_begin(i2c_num, cmd, 1000 / portTICK_RATE_MS);
    i2c_cmd_link_delete(cmd);
    return ret;
}

/**
 * @brief Test code to write esp-i2c-slave
 *        Master device write data to slave(both esp32),
 *        the data will be stored in slave buffer.
 *        We can read them out from slave buffer.
 *
 * ___________________________________________________________________
 * | start | slave_addr + wr_bit + ack | write n bytes + ack  | stop |
 * --------|---------------------------|----------------------|------|
 *
 */
static esp_err_t i2c_example_master_write_slave(i2c_port_t i2c_num, uint8_t* data_wr, size_t size)
{
    i2c_cmd_handle_t cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, ( ESP_SLAVE_ADDR << 1 ) | WRITE_BIT, ACK_CHECK_EN);
    i2c_master_write(cmd, data_wr, size, ACK_CHECK_EN);
    i2c_master_stop(cmd);
    esp_err_t ret = i2c_master_cmd_begin(i2c_num, cmd, 1000 / portTICK_RATE_MS);
    i2c_cmd_link_delete(cmd);
    return ret;
}

/**
 * @brief test code to write esp-i2c-slave
 *
 * 1. set mode
 * _________________________________________________________________
 * | start | slave_addr + wr_bit + ack | write 1 byte + ack  | stop |
 * --------|---------------------------|---------------------|------|
 * 2. wait more than 24 ms
 * 3. read data
 * ______________________________________________________________________________________
 * | start | slave_addr + rd_bit + ack | read 1 byte + ack  | read 1 byte + nack | stop |
 * --------|---------------------------|--------------------|--------------------|------|
 */
static esp_err_t i2c_example_master_sensor_test(i2c_port_t i2c_num, uint8_t* data_h, uint8_t* data_l)
{
    i2c_cmd_handle_t cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, BH1750_SENSOR_ADDR << 1 | WRITE_BIT, ACK_CHECK_EN);
    i2c_master_write_byte(cmd, BH1750_CMD_START, ACK_CHECK_EN);
    i2c_master_stop(cmd);
    int ret = i2c_master_cmd_begin(i2c_num, cmd, 1000 / portTICK_RATE_MS);
    i2c_cmd_link_delete(cmd);
    if (ret == ESP_FAIL) {
        return ret;
    }
    vTaskDelay(30 / portTICK_RATE_MS);

    cmd = i2c_cmd_link_create();
    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, BH1750_SENSOR_ADDR << 1 | READ_BIT, ACK_CHECK_EN);
    i2c_master_read_byte(cmd, data_h, ACK_VAL);
    i2c_master_read_byte(cmd, data_l, NACK_VAL);
    i2c_master_stop(cmd);
    ret = i2c_master_cmd_begin(i2c_num, cmd, 1000 / portTICK_RATE_MS);
    i2c_cmd_link_delete(cmd);
    if (ret == ESP_FAIL) {
        return ESP_FAIL;
    }
    return ESP_OK;
}

/**
 * @brief i2c master initialization
 */
static void i2c_example_master_init()
{
    int i2c_master_port = I2C_EXAMPLE_MASTER_NUM;
    i2c_config_t conf;
    conf.mode = I2C_MODE_MASTER;
    conf.sda_io_num = I2C_EXAMPLE_MASTER_SDA_IO;
    conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
    conf.scl_io_num = I2C_EXAMPLE_MASTER_SCL_IO;
    conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
    conf.master.clk_speed = I2C_EXAMPLE_MASTER_FREQ_HZ;
    i2c_param_config(i2c_master_port, &conf);
    i2c_driver_install(i2c_master_port, conf.mode,
                       I2C_EXAMPLE_MASTER_RX_BUF_DISABLE,
                       I2C_EXAMPLE_MASTER_TX_BUF_DISABLE, 0);
}

/**
 * @brief i2c slave initialization
 */
static void i2c_example_slave_init()
{
    int i2c_slave_port = I2C_EXAMPLE_SLAVE_NUM;
    i2c_config_t conf_slave;
    conf_slave.sda_io_num = I2C_EXAMPLE_SLAVE_SDA_IO;
    conf_slave.sda_pullup_en = GPIO_PULLUP_ENABLE;
    conf_slave.scl_io_num = I2C_EXAMPLE_SLAVE_SCL_IO;
    conf_slave.scl_pullup_en = GPIO_PULLUP_ENABLE;
    conf_slave.mode = I2C_MODE_SLAVE;
    conf_slave.slave.addr_10bit_en = 0;
    conf_slave.slave.slave_addr = ESP_SLAVE_ADDR;
    i2c_param_config(i2c_slave_port, &conf_slave);
    i2c_driver_install(i2c_slave_port, conf_slave.mode,
                       I2C_EXAMPLE_SLAVE_RX_BUF_LEN,
                       I2C_EXAMPLE_SLAVE_TX_BUF_LEN, 0);
}

/**
 * @brief test function to show buffer
 */
static void disp_buf(uint8_t* buf, int len)
{
    int i;
    for (i = 0; i < len; i++) {
        printf("%02x ", buf[i]);
        if (( i + 1 ) % 16 == 0) {
            printf("\n");
        }
    }
    printf("\n");
}

static void i2c_test_task(void* arg)
{
    int i = 0;
    int ret;
    uint32_t task_idx = (uint32_t) arg;
    uint8_t* data = (uint8_t*) malloc(DATA_LENGTH);
    uint8_t* data_wr = (uint8_t*) malloc(DATA_LENGTH);
    uint8_t* data_rd = (uint8_t*) malloc(DATA_LENGTH);
    uint8_t sensor_data_h, sensor_data_l;

    while (1) {
        ret = i2c_example_master_sensor_test( I2C_EXAMPLE_MASTER_NUM, &sensor_data_h, &sensor_data_l);
        xSemaphoreTake(print_mux, portMAX_DELAY);
        printf("*******************\n");
        printf("TASK[%d]  MASTER READ SENSOR( BH1750 )\n", task_idx);
        printf("*******************\n");
        if (ret == ESP_OK) {
            printf("data_h: %02x\n", sensor_data_h);
            printf("data_l: %02x\n", sensor_data_l);
            printf("sensor val: %f\n", ( sensor_data_h << 8 | sensor_data_l ) / 1.2);
        } else {
            printf("No ack, sensor not connected...skip...\n");
        }
        xSemaphoreGive(print_mux);
        vTaskDelay(( DELAY_TIME_BETWEEN_ITEMS_MS * ( task_idx + 1 ) ) / portTICK_RATE_MS);

        //---------------------------------------------------
        for (i = 0; i < DATA_LENGTH; i++) {
            data[i] = i;
        }
        size_t d_size = i2c_slave_write_buffer(I2C_EXAMPLE_SLAVE_NUM, data, RW_TEST_LENGTH, 1000 / portTICK_RATE_MS);
        if (d_size == 0) {
            printf("i2c slave tx buffer full\n");
            ret = i2c_example_master_read_slave(I2C_EXAMPLE_MASTER_NUM, data_rd, DATA_LENGTH);
        } else {
            ret = i2c_example_master_read_slave(I2C_EXAMPLE_MASTER_NUM, data_rd, RW_TEST_LENGTH);
        }
        xSemaphoreTake(print_mux, portMAX_DELAY);
        printf("*******************\n");
        printf("TASK[%d]  MASTER READ FROM SLAVE\n", task_idx);
        printf("*******************\n");
        printf("====TASK[%d] Slave buffer data ====\n", task_idx);
        disp_buf(data, d_size);
        if (ret == ESP_OK) {
            printf("====TASK[%d] Master read ====\n", task_idx);
            disp_buf(data_rd, d_size);
        } else {
            printf("Master read slave error, IO not connected...\n");
        }
        xSemaphoreGive(print_mux);
        vTaskDelay(( DELAY_TIME_BETWEEN_ITEMS_MS * ( task_idx + 1 ) ) / portTICK_RATE_MS);
        //---------------------------------------------------
        int size;
        for (i = 0; i < DATA_LENGTH; i++) {
            data_wr[i] = i + 10;
        }
        //we need to fill the slave buffer so that master can read later
        ret = i2c_example_master_write_slave( I2C_EXAMPLE_MASTER_NUM, data_wr, RW_TEST_LENGTH);
        if (ret == ESP_OK) {
            size = i2c_slave_read_buffer( I2C_EXAMPLE_SLAVE_NUM, data, RW_TEST_LENGTH, 1000 / portTICK_RATE_MS);
        }
        xSemaphoreTake(print_mux, portMAX_DELAY);
        printf("*******************\n");
        printf("TASK[%d]  MASTER WRITE TO SLAVE\n", task_idx);
        printf("*******************\n");
        printf("----TASK[%d] Master write ----\n", task_idx);
        disp_buf(data_wr, RW_TEST_LENGTH);
        if (ret == ESP_OK) {
            printf("----TASK[%d] Slave read: [%d] bytes ----\n", task_idx, size);
            disp_buf(data, size);
        } else {
            printf("TASK[%d] Master write slave error, IO not connected....\n", task_idx);
        }
        xSemaphoreGive(print_mux);
        vTaskDelay(( DELAY_TIME_BETWEEN_ITEMS_MS * ( task_idx + 1 ) ) / portTICK_RATE_MS);
    }
}

void app_main()
{
    print_mux = xSemaphoreCreateMutex();
    i2c_example_slave_init();
    i2c_example_master_init();

    xTaskCreate(i2c_test_task, "i2c_test_task_0", 1024 * 2, (void* ) 0, 10, NULL);
    xTaskCreate(i2c_test_task, "i2c_test_task_1", 1024 * 2, (void* ) 1, 10, NULL);
}