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refactor (cxx): C++ I2C example now uses MPU9250 instead of MCP9808
Also fixes the documentation of I2CTransfer::sync_transfer().
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@ -229,7 +229,7 @@ public:
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std::vector<uint8_t> sync_read(uint8_t i2c_addr, size_t n_bytes);
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/**
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* Do a simple asynchronous write-read transfer.
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* Do a simple synchronous write-read transfer.
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*
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* First, \c write_data will be written to the bus, then a number of \c read_n_bytes will be read from the bus
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* with a repeated start condition. The slave device is determined by \c i2c_addr.
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@ -1,49 +0,0 @@
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# Example: C++ I2C sensor read for MCP9808
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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This example demonstrates usage of C++ exceptions in ESP-IDF.
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In this example, the `sdkconfig.defaults` file sets the `CONFIG_COMPILER_CXX_EXCEPTIONS` option.
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This enables both compile time support (`-fexceptions` compiler flag) and run-time support for C++ exception handling.
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This is necessary for the C++ I2C API.
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## How to use example
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### Hardware Required
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An MCP9808 sensor and any commonly available ESP32 development board.
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Pullups aren't necessary as the default pullups are enabled in the I2CMaster class.
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### Configure the project
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```
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idf.py menuconfig
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```
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### Build and Flash
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```
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idf.py -p PORT flash monitor
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```
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(Replace PORT with the name of the serial port.)
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(To exit the serial monitor, type ``Ctrl-]``.)
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See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
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## Example Output
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If the sensor is read correctly:
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```
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Current temperature: 24.875
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```
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If something went wrong:
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```
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I2C Exception with error: ESP_FAIL (-1)
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Coulnd't read sensor!
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```
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@ -1,2 +0,0 @@
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idf_component_register(SRCS "sensor_mcp9808.cpp"
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INCLUDE_DIRS ".")
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@ -1,54 +0,0 @@
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/* ESP MCP9808 Sensor/I2C C++ Example
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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Unless required by applicable law or agreed to in writing, this
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software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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*/
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#include <iostream>
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#include "i2c_cxx.hpp"
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using namespace std;
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using namespace idf;
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#define ADDR 0x18
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#define I2C_MASTER_NUM I2C_NUM_0 /*!< I2C port number for master dev */
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#define I2C_MASTER_SCL_IO 19 /*!< gpio number for I2C master clock */
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#define I2C_MASTER_SDA_IO 18 /*!< gpio number for I2C master data */
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#define MCP_9808_TEMP_REG 0x05
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/**
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* Calculates the temperature of the MCP9808 from the read msb and lsb. Loosely adapted from the MCP9808's datasheet.
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*/
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float calc_temp(uint8_t msb, uint8_t lsb) {
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float temperature;
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msb &= 0x1F;
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bool sign = msb & 0x10;
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if (sign) {
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msb &= 0x0F;
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temperature = 256 - (msb * 16 + (float) lsb / 16);
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} else {
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temperature = (msb * 16 + (float) lsb / 16);
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}
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return temperature;
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}
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extern "C" void app_main(void)
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{
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try {
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// creating master bus, writing temperature register pointer and reading the value
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shared_ptr<I2CMaster> master(new I2CMaster(I2C_MASTER_NUM, I2C_MASTER_SCL_IO, I2C_MASTER_SDA_IO, 400000));
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master->sync_write(ADDR, {MCP_9808_TEMP_REG});
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vector<uint8_t> data = master->sync_read(ADDR, 2);
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cout << "Current temperature: " << calc_temp(data[0], data[1]) << endl;
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} catch (const I2CException &e) {
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cout << "I2C Exception with error: " << e.what();
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cout << " (" << e.error<< ")" << endl;
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cout << "Coulnd't read sensor!" << endl;
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}
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}
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@ -5,4 +5,4 @@ cmake_minimum_required(VERSION 3.5)
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set(EXTRA_COMPONENT_DIRS "$ENV{IDF_PATH}/examples/cxx/experimental/experimental_cpp_component")
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include($ENV{IDF_PATH}/tools/cmake/project.cmake)
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project(sensor_mcp9808)
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project(simple_i2c_rw_example)
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60
examples/cxx/experimental/simple_i2c_rw_example/README.md
Normal file
60
examples/cxx/experimental/simple_i2c_rw_example/README.md
Normal file
@ -0,0 +1,60 @@
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# Example: C++ I2C sensor read for MPU9250
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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This example demonstrates usage of C++ exceptions in ESP-IDF. It is the C++ equivalent to the [I2C Simple Example](../../../peripherals/i2c/i2c_simple/) which is written in C.
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In this example, the `sdkconfig.defaults` file sets the `CONFIG_COMPILER_CXX_EXCEPTIONS` option. This enables both compile time support (`-fexceptions` compiler flag) and run-time support for C++ exception handling. This is necessary for the C++ I2C API.
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## How to Use This Example
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### Hardware Required
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To run this example, you should have one ESP32, ESP32-S series or ESP32-C series based development board as well as an MPU9250. MPU9250 is an inertial measurement unit, which contains an accelerometer, gyroscope as well as a magnetometer, for more information about it, you can read the [datasheet of the MPU9250 sensor](https://invensense.tdk.com/wp-content/uploads/2015/02/PS-MPU-9250A-01-v1.1.pdf).
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#### Pin Assignment:
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**Note:** The following pin assignments are used by default, you can change these in the `menuconfig` .
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| | SDA | SCL |
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| ---------------- | -------------- | -------------- |
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| ESP I2C Master | I2C_MASTER_SDA | I2C_MASTER_SCL |
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| MPU9250 Sensor | SDA | SCL |
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For the actual default value of `I2C_MASTER_SDA` and `I2C_MASTER_SCL`, see `Example Configuration` in `menuconfig`.
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**Note:** There's no need to add external pull-up resistors for SDA/SCL pins, because the driver will enable the internal pull-up resistors.
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### Configure the project
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```
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idf.py menuconfig
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```
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### Build and Flash
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```
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idf.py -p <PORT> flash monitor
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```
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Replace <PORT> with the name of the serial port. To exit the serial monitor, type ``Ctrl-]``.
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See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
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## Example Output
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If the sensor is read correctly:
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```bash
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I (328) i2c-simple-example: I2C initialized successfully
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I (338) i2c-simple-example: WHO_AM_I = 71
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I (338) i2c-simple-example: I2C de-initialized successfully
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```
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If something went wrong:
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```
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I2C Exception with error: ESP_FAIL (-1)
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Couldn't read sensor!
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```
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@ -0,0 +1,2 @@
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idf_component_register(SRCS "simple_i2c_rw_example.cpp"
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INCLUDE_DIRS ".")
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@ -0,0 +1,17 @@
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menu "Example Configuration"
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config I2C_MASTER_SCL
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int "SCL GPIO Num"
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default 6 if IDF_TARGET_ESP32C3
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default 19 if IDF_TARGET_ESP32 || IDF_TARGET_ESP32S2 || IDF_TARGET_ESP32S3
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help
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GPIO number for I2C Master clock line.
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config I2C_MASTER_SDA
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int "SDA GPIO Num"
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default 5 if IDF_TARGET_ESP32C3
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default 18 if IDF_TARGET_ESP32 || IDF_TARGET_ESP32S2 || IDF_TARGET_ESP32S3
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help
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GPIO number for I2C Master data line.
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endmenu
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@ -0,0 +1,54 @@
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/*
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* SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: CC0
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*
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* MPU9250 I2C Sensor C++ Example
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*
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* This example code is in the Public Domain (or CC0 licensed, at your option.)
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*
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* Unless required by applicable law or agreed to in writing, this
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* software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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* CONDITIONS OF ANY KIND, either express or implied.
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*/
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#include <iostream>
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#include "esp_log.h"
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#include "i2c_cxx.hpp"
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using namespace std;
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using namespace idf;
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static const char *TAG = "i2c-cxx-simple-example";
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#define I2C_MASTER_NUM 0 /*!< I2C master i2c port number, the number of i2c peripheral interfaces
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available will depend on the chip */
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#define I2C_MASTER_SCL_IO CONFIG_I2C_MASTER_SCL /*!< GPIO number used for I2C master clock */
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#define I2C_MASTER_SDA_IO CONFIG_I2C_MASTER_SDA /*!< GPIO number used for I2C master data */
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#define MPU9250_SENSOR_ADDR 0x68 /*!< Slave address of the MPU9250 sensor */
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#define MPU9250_WHO_AM_I_REG_ADDR 0x75 /*!< Register addresses of the "who am I" register */
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extern "C" void app_main(void)
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{
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try {
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// creating master bus
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shared_ptr<I2CMaster> master(new I2CMaster(I2C_MASTER_NUM, I2C_MASTER_SCL_IO, I2C_MASTER_SDA_IO, 400000));
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ESP_LOGI(TAG, "I2C initialized successfully");
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// writing the pointer to the WHO_AM_I register to the device
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master->sync_write(MPU9250_SENSOR_ADDR, {MPU9250_WHO_AM_I_REG_ADDR});
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// reading back the value of WHO_AM_I register which should be 71
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vector<uint8_t> data = master->sync_read(MPU9250_SENSOR_ADDR, 2);
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ESP_LOGI(TAG, "WHO_AM_I = %X", data[0]);
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} catch (const I2CException &e) {
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cout << "I2C Exception with error: " << e.what();
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cout << " (" << e.error<< ")" << endl;
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cout << "Couldn't read sensor!" << endl;
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}
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// The I2CMaster object is de-initialized in its destructor when going out of scope.
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ESP_LOGI(TAG, "I2C de-initialized successfully");
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}
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...
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I (0) cpu_start: Starting scheduler on APP CPU.
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E (434) spi: spicommon_bus_initialize_io(429): mosi not valid
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Coulnd't read SPI!
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Couldn't read SPI!
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```
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If the SPI pins are not connected properly, the resulting read may just return 0, this error can not be detected:
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this_thread::sleep_for(std::chrono::seconds(2));
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} catch (const SPIException &e) {
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cout << "Coulnd't read SPI!" << endl;
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cout << "Couldn't read SPI!" << endl;
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}
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}
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@ -12,7 +12,7 @@ If you have a new I2C application to go (for example, read the temperature data
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### Hardware Required
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To run this example, you should have one ESP32, ESP32-S or ESP32-C based development board as well as a MPU9250. MPU9250 is a inertial measurement unit, which contains a accelerometer, gyroscope as well as a magnetometer, for more information about it, you can read the [PDF](https://invensense.tdk.com/wp-content/uploads/2015/02/PS-MPU-9250A-01-v1.1.pdf) of this sensor.
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To run this example, you should have one ESP32, ESP32-S or ESP32-C based development board as well as a MPU9250. MPU9250 is a inertial measurement unit, which contains a accelerometer, gyroscope as well as a magnetometer, for more information about it, you can read the [datasheet of the MPU9250 sensor](https://invensense.tdk.com/wp-content/uploads/2015/02/PS-MPU-9250A-01-v1.1.pdf).
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#### Pin Assignment:
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@ -26,7 +26,7 @@ To run this example, you should have one ESP32, ESP32-S or ESP32-C based develop
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For the actual default value of `I2C_MASTER_SDA` and `I2C_MASTER_SCL` see `Example Configuration` in `menuconfig`.
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**Note: ** There’s no need to add an external pull-up resistors for SDA/SCL pin, because the driver will enable the internal pull-up resistors.
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**Note:** There's no need to add an external pull-up resistors for SDA/SCL pin, because the driver will enable the internal pull-up resistors.
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### Build and Flash
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@ -41,7 +41,7 @@ See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/l
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```bash
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I (328) i2c-simple-example: I2C initialized successfully
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I (338) i2c-simple-example: WHO_AM_I = 71
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I (338) i2c-simple-example: I2C unitialized successfully
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I (338) i2c-simple-example: I2C de-initialized successfully
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```
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## Troubleshooting
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@ -93,5 +93,5 @@ void app_main(void)
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ESP_ERROR_CHECK(mpu9250_register_write_byte(MPU9250_PWR_MGMT_1_REG_ADDR, 1 << MPU9250_RESET_BIT));
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ESP_ERROR_CHECK(i2c_driver_delete(I2C_MASTER_NUM));
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ESP_LOGI(TAG, "I2C unitialized successfully");
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ESP_LOGI(TAG, "I2C de-initialized successfully");
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}
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