ed1e32f583
Reported from different sources from github or bbs: https://github.com/espressif/esp-idf/issues/680 https://github.com/espressif/esp-idf/issues/922 We tested reading several sensor or other I2C slave devices, if the power and SDA/SCL wires are in proper condition, everything works find with reading the slave. If we remove the power supply for the slave during I2C is reading, or directly connect SDA or SCL to ground, this would cause the I2C FSM get stuck in wrong state, all we can do is the reset the I2C hardware in this case. After this commit, no matter whether the power supply of I2C slave is removed or SDA / SCL are shorted to ground, the driver can recover from wrong state. We are not sure whether this the save issue with the reported one yet, but to make the driver more robust. Further information: 1. For I2C master mode, we have tested different situations, e.g., to short the SDA/SCL directly to GND/VCC, to short the SDA to SCL, to un-plug the slave device, to power off the slave device. Under all of those situations, this version of driver can recover and keep working. 2. Some slave device will die by accident and keep the SDA in low level, in this case, master should send several clock to make the slave release the bus. 3. Slave mode of ESP32 might also get in wrong state that held the SDA low, in this case, master device could send a stop signal to make esp32 slave release the bus. Modifications: 1. Disable I2C_MASTER_TRAN_COMP interrupt to void extra interrupt. 2. Disable un-used timeout interrupt for slave. 3. Add bus reset if error detected for master mode. 4. Add bus clear if SDA level is low when error detected. 5. Modify the argument type of i2c_set_pin. 6. add API to set timeout value 7. add parameter check for timing APIs |
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| README.md | ||
Examples
This directory contains a growing number of simple example projects for esp-idf. These are intended to show basic esp-idf functionality, and to provide you can use for your own projects.
Using Examples
Building examples is the same as building any other project:
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Follow the setup instructions in the top-level esp-idf README.
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Set
IDF_PATHenvironment variable to point to the path to the esp-idf top-level directory. -
Change into the directory of the example you'd like to build.
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make menuconfigto configure the example. Most examples require a simple WiFi SSID & password via this configuration. -
maketo build the example. -
Follow the printed instructions to flash, or run
make flash.
Copying Examples
Each example is a standalone project. The examples do not have to be inside the esp-idf directory. You can copy an example directory to anywhere on your computer in order to make a copy that you can modify and work with.
The IDF_PATH environment variable is the only thing that connects the example to the rest of the esp-idf system.
If you're looking for a more bare-bones project to start from, try esp-idf-template.
Contributing Examples
If you have a new example you think we'd like, please consider sending it to us as a Pull Request.
Please read the esp-idf CONTRIBUTING.rst file which lays out general contribution rules.
In addition, here are some tips for creating good examples:
- A good example is documented and the basic options can be configured.
- A good example does not contain a lot of code. If there is a lot of generic code in the example, consider refactoring that code into a standalone component and then use the component's API in your example.
- Names (of files, functions, variables, etc.) inside examples should be distinguishable from names of other parts of IDF (ideally, use
examplein names.) - Functions and variables used inside examples should be declared static where possible.
- Examples should demonstrate one distinct thing each. Avoid multi-purposed "demo" examples, split these into multiple examples instead.
- Examples must be licensed under the Apache License 2.0 or (preferably for examples) if possible you can declare the example to be Public Domain / Creative Commons Zero.