KonstantinKondrashov
5ed8388f6b
It gave us a better performance of RSA operations. (2~11 times) The old modexp implementation (Z = X ^ Y mod M) loaded all the data into the hw registers and was waiting for completion, but due to the hardware RSA implementation, the calculations always started with 4096 bit, which took a lot of time. Measurement results (measurements were made for keys: 2048, 3072 and 4096 bits) (Old) - Sliding-window exponentiation (HAC 14.85): keysize = 2048 bits RSA key operation (performance): public [93206 us], private [280189 us] keysize = 3072 bits RSA key operation (performance): public [293614 us], private [858157 us] keysize = 4096 bits RSA key operation (performance): public [653192 us], private [1912126 us] Instead (Old) - Sliding-window exponentiation (HAC 14.85) was implemented (New) - Montgomery exponentiation (HAC 14.94) which showed better performance on private and public keys. keysize = 2048 bits RSA key operation (performance): public [14504 us], private [149456 us] keysize = 3072 bits RSA key operation (performance): public [35073 us], private [392743 us] keysize = 4096 bits RSA key operation (performance): public [58650 us], private [787186 us] For this reason, the old implementation was removed and the MBEDTLS_HARDWARE_MPI option was turned on by default. Why the MPI_INTERRUPT option is removed: the old implementation used calculations on the hardware and it took a lot of time (10ms - 500ms). And in order not to stand idle while waiting for completion, an interrupt option was added. This made it possible to carry out other tasks during the calculation, and this one to block. The new method is free from such a drawback and the maximum duration of one RSA HW operation does not exceed 70us (usually 2-70 μs). This option is no longer needed. Closes: IDF-965
Espressif IoT Development Framework
ESP-IDF is the official development framework for the ESP32 chip.
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 Getting Started guide for a full list of required steps with details.)
- Install host build dependencies mentioned in Getting Started guide.
- Add
tools/directory to the PATH - Run
python -m pip install -r requirements.txtto install Python dependencies
Configuring the Project
idf.py menuconfig
- Opens a text-based configuration menu for the project.
- Use up & down arrow keys to navigate the menu.
- Use Enter key to go into a submenu, Escape key to go out or to exit.
- Type
?to see a help screen. Enter key exits the help screen. - Use Space key, or
YandNkeys to enable (Yes) and disable (No) configuration items with checkboxes "[*]" - Pressing
?while highlighting a configuration item displays help about that item. - Type
/to search the configuration items.
Once done configuring, press Escape multiple times to exit and say "Yes" to save the new configuration when prompted.
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
-
Documentation for the latest version: https://docs.espressif.com/projects/esp-idf/. This documentation is built from the docs directory of this repository.
-
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.
-
If you're interested in contributing to ESP-IDF, please check the Contributions Guide.