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1. The 2nd bootloader always call `rom_spiflash_unlock()`, but never help to clear the WEL bit when exit. This may cause system unstability. This commit helps to clear WEL when flash configuration is done. **RISK:** When the app starts, it didn't have to clear the WEL before it actually write/erase. But now the very first write/erase operation should be done after a WEL clear. Though the risk is little (all the following write/erase also need to clear the WEL), we still have to test this carefully, especially for those functions used by the OTA. 2. The `rom_spiflash_unlock()` function in the patch of ESP32 may (1) trigger the QPI, (2) clear the QE or (3) fail to unlock the ISSI chips. Status register bitmap of ISSI chip and GD chip: | SR | ISSI | GD25LQ32C | | -- | ---- | --------- | | 0 | WIP | WIP | | 1 | WEL | WEL | | 2 | BP0 | BP0 | | 3 | BP1 | BP1 | | 4 | BP2 | BP2 | | 5 | BP3 | BP3 | | 6 | QE | BP4 | | 7 | SRWD | SRP0 | | 8 | | SRP1 | | 9 | | QE | | 10 | | SUS2 | | 11 | | LB1 | | 12 | | LB2 | | 13 | | LB3 | | 14 | | CMP | | 15 | | SUS1 | QE bit of other chips are at the bit 9 of the status register (i.e. bit 1 of SR2), which should be read by RDSR2 command. However, the RDSR2 (35H, Read Status 2) command for chip of other vendors happens to be the QIOEN (Enter QPI mode) command of ISSI chips. When the `rom_spiflash_unlock()` function trys to read SR2, it may trigger the QPI of ISSI chips. Moreover, when `rom_spiflash_unlock()` try to clear the BP4 bit in the status register, QE (bit 6) of ISSI chip may be cleared by accident. Or if the ISSI chip doesn't accept WRSR command with argument of two bytes (since it only have status register of one byte), it may fail to clear the other protect bits (BP0~BP3) as expected. This commit makes the `rom_spiflash_unlock()` check whether the vendor is issi. if so, `rom_spiflash_unlock()` only send RDSR to read the status register, send WRSR with only 1 byte argument, and also avoid clearing the QE bit (bit 6). 3. `rom_spiflash_unlock()` always send WRSR command to clear protection bits even when there is no protection bit active. And the execution of clearing status registers, which takes about 700us, will also happen even when there's no bits cleared. This commit skips the clearing of status register if there is no protection bits active. Also move the execute_flash_command to be a bootloader API; move implementation of spi_flash_wrap_set to the bootloader
Espressif IoT Development Framework
ESP-IDF is the official development framework for the ESP32 chip provided for Windows, Linux and macOS.
Developing With ESP-IDF
Setting Up ESP-IDF
See setup guides for detailed instructions to set up the ESP-IDF:
- Getting Started Guide for the stable ESP-IDF version
- Getting Started Guide for the latest (master branch) ESP-IDF version
Non-GitHub forks
ESP-IDF uses relative locations as its submodules URLs (.gitmodules). So they link to GitHub.
If ESP-IDF is forked to a Git repository which is not on GitHub, you will need to run the script
tools/set-submodules-to-github.sh after git clone.
The script sets absolute URLs for all submodules, allowing git submodule update --init --recursive to complete.
If cloning ESP-IDF from GitHub, this step is not needed.
Finding a Project
As well as the esp-idf-template project mentioned in Getting Started, ESP-IDF comes with some example projects in the examples directory.
Once you've found the project you want to work with, change to its directory and you can configure and build it.
To start your own project based on an example, copy the example project directory outside of the ESP-IDF directory.
Quick Reference
See the Getting Started guide links above for a detailed setup guide. This is a quick reference for common commands when working with ESP-IDF projects:
Setup Build Environment
(See the Getting Started guide listed above for a full list of required steps with more details.)
- Install host build dependencies mentioned in the Getting Started guide.
- Run the install script to set up the build environment. The options include
install.batorinstall.ps1for Windows, andinstall.shfor Unix shells. - Run the export script on Windows (
export.bat) or source it on Unix (source export.sh) in every shell environment before using ESP-IDF.
Configuring the Project
idf.py menuconfig opens a text-based configuration menu where you can configure the project.
Compiling the Project
idf.py build
... will compile app, bootloader and generate a partition table based on the config.
Flashing the Project
When the build finishes, it will print a command line to use esptool.py to flash the chip. However you can also do this automatically by running:
idf.py -p PORT flash
Replace PORT with the name of your serial port (like COM3 on Windows, /dev/ttyUSB0 on Linux, or /dev/cu.usbserial-X on MacOS. If the -p option is left out, idf.py flash will try to flash the first available serial port.
This will flash the entire project (app, bootloader and partition table) to a new chip. The settings for serial port flashing can be configured with idf.py menuconfig.
You don't need to run idf.py build before running idf.py flash, idf.py flash will automatically rebuild anything which needs it.
Viewing Serial Output
The idf.py monitor target uses the idf_monitor tool to display serial output from the ESP32. idf_monitor also has a range of features to decode crash output and interact with the device. Check the documentation page for details.
Exit the monitor by typing Ctrl-].
To build, flash and monitor output in one pass, you can run:
idf.py flash monitor
Compiling & Flashing Only the App
After the initial flash, you may just want to build and flash just your app, not the bootloader and partition table:
idf.py app- build just the app.idf.py app-flash- flash just the app.
idf.py app-flash will automatically rebuild the app if any source files have changed.
(In normal development there's no downside to reflashing the bootloader and partition table each time, if they haven't changed.)
Erasing Flash
The idf.py flash target does not erase the entire flash contents. However it is sometimes useful to set the device back to a totally erased state, particularly when making partition table changes or OTA app updates. To erase the entire flash, run idf.py erase_flash.
This can be combined with other targets, ie idf.py -p PORT erase_flash flash will erase everything and then re-flash the new app, bootloader and partition table.
Resources
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Documentation for the latest version: https://docs.espressif.com/projects/esp-idf/. This documentation is built from the docs directory of this repository.
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The esp32.com forum is a place to ask questions and find community resources.
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Check the Issues section on github if you find a bug or have a feature request. Please check existing Issues before opening a new one.
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If you're interested in contributing to ESP-IDF, please check the Contributions Guide.