# esp-serial-flasher `esp-serial-flasher` is a portable C library for flashing or loading apps to RAM of Espressif SoCs from other host microcontrollers. ## Using the library Espressif SoCs are normally programmed via serial interface (UART). The port layer for the given host microcontroller has to be implemented if not available. Details can be found in section below. Supported **host** microcontrollers: - STM32 - Raspberry Pi SBC - ESP32 - Any MCU running Zephyr OS Supported **target** microcontrollers: - ESP32 - ESP8266 - ESP32-S2 - ESP32-S3 - ESP32-C3 - ESP32-C2 - ESP32-H2 - ESP32-C6 Supported hardware interfaces: - UART - SPI (only for RAM download, experimental) For example usage check the `examples` directory. ## Supporting a new host target In order to support a new target, following functions have to be implemented by user: - `loader_port_read()` - `loader_port_write()` - `loader_port_enter_bootloader()` - `loader_port_delay_ms()` - `loader_port_start_timer()` - `loader_port_remaining_time()` For the SPI interface ports - `loader_port_spi_set_cs()` needs to be implemented as well. The following functions are part of the [io.h](include/io.h) header for convenience, however, the user does not have to strictly follow function signatures, as there are not called directly from library. - `loader_port_change_transmission_rate()` - `loader_port_reset_target()` - `loader_port_debug_print()` Prototypes of all functions mentioned above can be found in [io.h](include/io.h). ## Configuration These are the configuration toggles available to the user: * `SERIAL_FLASHER_INTERFACE_UART/SERIAL_FLASHER_INTERFACE_SPI` This defines the hardware interface to use. SPI interface only supports RAM download mode and is in experimental stage and can undergo changes. Default: SERIAL_FLASHER_INTERFACE_UART * `MD5_ENABLED` If enabled, `esp-serial-flasher` is capable of verifying flash integrity after writing to flash. Default: Enabled > Warning: As ROM bootloader of the ESP8266 does not support MD5_CHECK, this option has to be disabled! * `SERIAL_FLASHER_RESET_HOLD_TIME_MS` This is the time for which the reset pin is asserted when doing a hard reset in milliseconds. Default: 100 * `SERIAL_FLASHER_BOOT_HOLD_TIME_MS` This is the time for which the boot pin is asserted when doing a hard reset in milliseconds. Default: 50 Configuration can be passed to `cmake` via command line: ``` cmake -DMD5_ENABLED=1 .. && cmake --build . ``` ### STM32 support The STM32 port makes use of STM32 HAL libraries, and these do not come with CMake support. In order to compile the project, `stm32-cmake` (a `CMake` support package) has to be pulled as submodule. ``` git clone --recursive https://github.com/espressif/esp-serial-flasher.git ``` If you have cloned this repository without the `--recursive` flag, you can initialize the submodule using the following command: ``` git submodule update --init ``` In addition to configuration parameters mentioned above, following definitions has to be set: - TOOLCHAIN_PREFIX: path to arm toolchain (i.e /home/user/gcc-arm-none-eabi-9-2019-q4-major) - STM32Cube_DIR: path to STM32 Cube libraries (i.e /home/user/STM32Cube/Repository/STM32Cube_FW_F4_V1.25.0) - STM32_CHIP: name of STM32 for which project should be compiled (i.e STM32F407VG) - PORT: STM32 This can be achieved by passing definitions to the command line, such as: ``` cmake -DTOOLCHAIN_PREFIX="/path_to_toolchain" -DSTM32Cube_DIR="path_to_stm32Cube" -DSTM32_CHIP="STM32F407VG" -DPORT="STM32" .. && cmake --build . ``` Alternatively, those variables can be set in the top level `cmake` directory: ``` set(TOOLCHAIN_PREFIX path_to_toolchain) set(STM32Cube_DIR path_to_stm32_HAL) set(STM32_CHIP STM32F407VG) set(PORT STM32) ``` ### Zephyr support The Zephyr port is ready to be integrated into Zephyr apps as a Zephyr module. In the manifest file (west.yml), add: ``` - name: esp-flasher url: https://github.com/espressif/esp-serial-flasher revision: master path: modules/lib/esp_flasher ``` And add ``` CONFIG_ESP_SERIAL_FLASHER=y CONFIG_CONSOLE_GETCHAR=y CONFIG_SERIAL_FLASHER_MD5_ENABLED=y ``` to the project configuration `prj.conf`. For the C/C++ source code, the example code provided in `examples/zephyr_example` can be used as a starting point. ## Licence Code is distributed under Apache 2.0 license. ## Known limitations Size of new binary image has to be known before flashing.
idf.py add-dependency "espressif/esp-serial-flasher^0.3.1"