This example shows how to override the default chip driver list provided by IDF. Please make sure the SPI_FLASH_OVERRIDE_CHIP_DRIVER_LIST config option is enabled when you build this project (though it should already be enabled by default via `sdkconfig.defaults`). See [the programming guide](https://docs.espressif.com/projects/esp-idf/en/stable/api-reference/storage/spi_flash_override_driver.html) for more details regarding this feature.
**CAUTION: This is only an example showing how to extend your own flash chip driver. Espressif doesn't guarantee the chip driver in the example is reliable for mass production, nor the reliability of the flash models that appear in this example. Please refer to the specification of your flash chip, or contact the flash vendor if you have any problems with the flash chip.**
(See the README.md file in the upper level 'examples' directory for more information about examples.)
## How to use example
Follow detailed instructions provided specifically for this example.
Select the instructions depending on Espressif chip installed on your development board:
- [ESP32 Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/stable/get-started/index.html)
- [ESP32-S2 Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/get-started/index.html)
## Example folder contents
The project **custom_flash_driver** contains one source file in C language [main.c](main/main.c). The file is located in folder [main](main).
The component **custom_chip_driver** placed under **components** folder, provides
ESP-IDF projects are built using CMake. The project build configuration is contained in `CMakeLists.txt` files that provide set of directives and instructions describing the project's source files and targets (executable, library, or both).
Below is short explanation of remaining files in the project folder.
```
├── CMakeLists.txt
├── sdkconfig.defaults Default options to add into sdkconfig file (mainly to enable the SPI_FLASH_OVERRIDE_CHIP_DRIVER_LIST option)
├── example_test.py Python script used for automated example testing
├── main
│ ├── CMakeLists.txt
│ ├── component.mk Component make file
│ └── main.c
├── components/custom_chip_driver
│ ├── CMakeLists.txt
│ ├── component.mk Component make file
│ ├── linker.lf Linker script to put the customized chip driver into internal RAM
│ ├── project_include.cmake Global cmake file to add dependency to spi_flash
│ ├── chip_drivers.c
│ └── spi_flash_chip_eon.c
├── Makefile Makefile used by legacy GNU Make
└── README.md This is the file you are currently reading
```
For more information on structure and contents of ESP-IDF projects, please refer to Section [Build System](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/build-system.html) of the ESP-IDF Programming Guide.
## Troubleshooting
* Program upload failure
* Hardware connection is not correct: run `idf.py -p PORT monitor`, and reboot your board to see if there are any output logs.
* The baud rate for downloading is too high: lower your baud rate in the `menuconfig` menu, and try again.
## Technical support and feedback
Please use the following feedback channels:
* For technical queries, go to the [esp32.com](https://esp32.com/) forum
* For a feature request or bug report, create a [GitHub issue](https://github.com/espressif/esp-idf/issues)
