153 lines
6.6 KiB
Markdown
153 lines
6.6 KiB
Markdown
# I2C Self-Test Example
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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## Overview
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This example demonstrates basic usage of I2C driver by running two tasks on I2C bus:
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1. Read external I2C sensor, here we take the BH1750 ambient light sensor (GY-30 module) for an example.
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2. Use one of ESP32’s I2C port (master mode) to read and write another I2C port (slave mode) in ESP32.
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If you have a new I2C application to go (for example, read the temperature data from external sensor with I2C interface), try this as a basic template, then add your own code.
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## How to use example
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### Hardware Required
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To run this example, you should have one ESP32 dev board (e.g. ESP32-WROVER Kit) or ESP32 core board (e.g. ESP32-DevKitC). Optionally, you can also connect an external sensor, here we choose the BH1750 just for an example. BH1750 is a digital ambient light sensor, for more information about it, you can read the [PDF](http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf) of this sensor.
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#### Pin Assignment:
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**Note:** The following pin assignments are used by default, yout can change these in the `menuconfig` .
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| | SDA | SCL |
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| ---------------- | ------ | ------ |
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| ESP32 I2C Master | GPIO18 | GPIO19 |
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| ESP32 I2C Slave | GPIO4 | GPIO5 |
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| BH1750 Sensor | SDA | SCL |
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- slave:
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- GPIO4 is assigned as the data signal of I2C slave port
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- GPIO5 is assigned as the clock signal of I2C slave port
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- master:
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- GPIO18 is assigned as the data signal of I2C master port
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- GPIO19 is assigned as the clock signal of I2C master port
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- Connection:
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- connect GPIO18 with GPIO4
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- connect GPIO19 with GPIO5
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- connect SDA/SCL of BH1750 sensor with GPIO18/GPIO19
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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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### Configure the project
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Open the project configuration menu (`idf.py menuconfig`). Then go into `Example Configuration` menu.
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- In the `I2C Master` submenu, you can set the pin number of SDA/SCL according to your board. Also you can modify the I2C port number and freauency of the master.
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- In the `I2C Slave` submenu, you can set the pin number of SDA/SCL according to your board. Also you can modify the I2C port number and address of the slave.
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- In the `BH1750 Sensor` submenu, you can choose the slave address of BH1750 accroding to the pin level of ADDR pin (if the pin level of ADDR is low then the address is `0x23`, otherwise it is `0x5c`). Here you can also control the operation mode of BH1750, each mode has a different resolution and measurement time. For example, in the `One Time L-Resolution` mode, the resolution is 4 Lux and measurement time is typically 16ms (higher resolution means longer measurement time). For more information, you can consult the datasheet of BH1750.
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### Build and Flash
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Enter `idf.py -p PORT flash monitor` to build, flash and monitor the project.
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(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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```bash
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I (6495) i2c-example: TASK[1] test cnt: 1
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*******************
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TASK[1] MASTER READ SENSOR( BH1750 )
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*******************
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data_h: 01
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data_l: d0
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sensor val: 386.67 [Lux]
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I (6695) i2c-example: TASK[0] test cnt: 2
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*******************
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TASK[0] MASTER READ SENSOR( BH1750 )
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*******************
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data_h: 01
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data_l: d0
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sensor val: 386.67 [Lux]
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*******************
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TASK[0] MASTER READ FROM SLAVE
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*******************
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====TASK[0] Slave buffer data ====
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00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
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10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
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20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
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30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
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40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
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50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
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60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
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70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
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====TASK[0] Master read ====
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00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
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10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
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20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
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30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
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40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
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50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
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60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
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70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
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*******************
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TASK[1] MASTER READ FROM SLAVE
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*******************
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====TASK[1] Slave buffer data ====
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00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
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10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
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20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
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30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
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40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
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50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
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60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
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70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
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====TASK[1] Master read ====
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00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
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10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
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20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
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30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
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40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
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50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
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60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
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70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
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*******************
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TASK[0] MASTER WRITE TO SLAVE
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*******************
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----TASK[0] Master write ----
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0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19
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1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29
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2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39
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3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49
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4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 59
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5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 69
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6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 79
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7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 89
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----TASK[0] Slave read: [128] bytes ----
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0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19
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1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29
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2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39
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3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 49
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4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 59
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5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 69
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6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 79
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7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 89
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```
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## Troubleshooting
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- BH1750 has two I2C address, which is decided by the voltage level of `ADDR` pin at start up. Make sure to check your schemetic before run this example.
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(For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you as soon as possible.)
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