Core2ForAWS_Port_A_I2C_Read

esp_err_t Core2ForAWS_Port_A_I2C_Read(I2CDevice_t device, uint32_t register_address, uint8_t *data, uint16_t length);

Reads from I2C peripheral connected to expansion port A.

This function reads a specified number of bytes starting from the specified register on the peripheral.

Note

Some peripherals do not support specifying a register address to read from. In this scenario, input the I2C_NO_REG macro as the register_address.

Read more about I2C capabilities of the ESP32 microcontroller and available APIs in the ESP-IDF.

The example code allocates a I2C heart rate sensor peripheral called port_A_peripheral of type I2CDevice_t that has an 8-bit device address of 0xA0 (right-shifted by 1-bit to be a 7-bit address) and using the standard baud rate. It then waits 10 seconds before looping to read from the peripheral, and since the device doesn't take a register address, it uses the macro I2C_NO_REG. The reading is printed every 10 seconds to the serial output.

Example:

#include <stdio.h>
#include <stdlib.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include "esp_log.h"
#include "core2forAWS.h"
 
#define DEVICE_ADDRESS 0xA0 >> 1
 
static const char *TAG = "MAIN";
 
void i2c_test_task(void * param){
    I2CDevice_t port_A_peripheral = Core2ForAWS_Port_A_I2C_Begin(DEVICE_ADDRESS, PORT_A_I2C_STANDARD_BAUD);
    
    vTaskDelay(pdMS_TO_TICKS(10000));
    for(;;){
        uint8_t heart_rate = 255;
        esp_err_t err = Core2ForAWS_Port_A_I2C_Read(port_A_peripheral, I2C_NO_REG, &heart_rate, 1);
        if(!err){
            ESP_LOGI(TAG, "Heart Rate — %ubpm", heart_rate);    
        }
        vTaskDelay(pdMS_TO_TICKS(10000));
    }
    Core2ForAWS_Port_A_I2C_Close(port_A_peripheral);
    vTaskDelete(NULL);
}
 
void app_main()
{
    Core2ForAWS_Init();
    xTaskCreatePinnedToCore(&i2c_test_task, "i2c_test_task", 4096, NULL, 5, NULL, 1);
}

Parameters

[in]	device	The device configuration pointer.
[in]	register_address	The address of the register to begin reading from.
[out]	data	The data read from the register(s).
[in]	length	The number of bytes to read from the peripheral.

Returns

The I2C device configuration.