================== Espressif ESP32-C6 ================== The ESP32-C6 is an ultra-low-power and highly integrated SoC with a RISC-V core and supports 2.4 GHz Wi-Fi 6, Bluetooth 5 (LE) and the 802.15.4 protocol. * Address Space - 800 KB of internal memory address space accessed from the instruction bus - 560 KB of internal memory address space accessed from the data bus - 1016 KB of peripheral address space - 8 MB of external memory virtual address space accessed from the instruction bus - 8 MB of external memory virtual address space accessed from the data bus - 480 KB of internal DMA address space * Internal Memory - 320 KB ROM - 512 KB SRAM (16 KB can be configured as Cache) - 16 KB of SRAM in RTC * External Memory - Up to 16 MB of external flash * Peripherals - 35 peripherals * GDMA - 7 modules are capable of DMA operations. ESP32-C6 Toolchain ================== A generic RISC-V toolchain can be used to build ESP32-C6 projects. It's recommended to use the same toolchain used by NuttX CI. Please refer to the Docker `container `_ and check for the current compiler version being used. For instance: .. code-block:: ############################################################################### # Build image for tool required by RISCV builds ############################################################################### FROM nuttx-toolchain-base AS nuttx-toolchain-riscv # Download the latest RISCV GCC toolchain prebuilt by xPack RUN mkdir riscv-none-elf-gcc && \ curl -s -L "https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/download/v13.2.0-2/xpack-riscv-none-elf-gcc-13.2.0-2-linux-x64.tar.gz" \ | tar -C riscv-none-elf-gcc --strip-components 1 -xz It uses the xPack's prebuilt toolchain based on GCC 13.2.0-2. Installing ---------- First, create a directory to hold the toolchain: .. code-block:: console $ mkdir -p /path/to/your/toolchain/riscv-none-elf-gcc Download and extract toolchain: .. code-block:: console $ curl -s -L "https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/download/v13.2.0-2/xpack-riscv-none-elf-gcc-13.2.0-2-linux-x64.tar.gz" \ | tar -C /path/to/your/toolchain/riscv-none-elf-gcc --strip-components 1 -xz Add the toolchain to your `PATH`: .. code-block:: console $ echo "export PATH=/path/to/your/toolchain/riscv-none-elf-gcc/bin:$PATH" >> ~/.bashrc You can edit your shell's rc files if you don't use bash. Building and flashing NuttX =========================== Bootloader and partitions ------------------------- NuttX can boot the ESP32-C6 directly using the so-called "Simple Boot". An externally-built 2nd stage bootloader is not required in this case as all functions required to boot the device are built within NuttX. Simple boot does not require any specific configuration (it is selectable by default if no other 2nd stage bootloader is used). For compatibility among other SoCs and future options of 2nd stage bootloaders, the commands ``make bootloader`` and the ``ESPTOOL_BINDIR`` option (for the ``make flash``) are kept (and ignored if Simple Boot is used). If other features are required, an externally-built 2nd stage bootloader is needed. The bootloader is built using the ``make bootloader`` command. This command generates the firmware in the ``nuttx`` folder. The ``ESPTOOL_BINDIR`` is used in the ``make flash`` command to specify the path to the bootloader. For compatibility among other SoCs and future options of 2nd stage bootloaders, the commands ``make bootloader`` and the ``ESPTOOL_BINDIR`` option (for the ``make flash``) can be used even if no externally-built 2nd stage bootloader is being built (they will be ignored if Simple Boot is used, for instance):: $ make bootloader .. note:: It is recommended that if this is the first time you are using the board with NuttX to perform a complete SPI FLASH erase. .. code-block:: console $ esptool.py erase_flash Building and flashing --------------------- First, make sure that ``esptool.py`` is installed. This tool is used to convert the ELF to a compatible ESP32-C6 image and to flash the image into the board. It can be installed with: ``pip install esptool==4.8.dev4``. Configure the NuttX project: ``./tools/configure.sh esp32c6-devkitc:nsh`` Run ``make`` to build the project. Note that the conversion mentioned above is included in the build process. The ``esptool.py`` is used to flash all the binaries. However, this is also included in the build process and we can build and flash with:: make flash ESPTOOL_PORT= ESPTOOL_BINDIR=./ Where ```` is typically ``/dev/ttyUSB0`` or similar and ``./`` is the path to the folder containing the externally-built 2nd stage bootloader for the ESP32-C6 as explained above. Debugging with ``openocd`` and ``gdb`` ====================================== Espressif uses a specific version of OpenOCD to support ESP32-C6: `openocd-esp32 `_. Please check `Building OpenOCD from Sources `_ for more information on how to build OpenOCD for ESP32-C6. You do not need an external JTAG to debug, the ESP32-C6 integrates a USB-to-JTAG adapter. .. note:: One must configure the USB drivers to enable JTAG communication. Please check `Configure USB Drivers `_ for more information. OpenOCD can then be used:: openocd -c 'set ESP_RTOS hwthread; set ESP_FLASH_SIZE 0' -f board/esp32c6-builtin.cfg If you want to debug with an external JTAG adapter it can be connected as follows: ============ =========== ESP32-C6 Pin JTAG Signal ============ =========== GPIO4 TMS GPIO5 TDI GPIO6 TCK GPIO7 TDO ============ =========== Furthermore, an efuse needs to be burnt to be able to debug:: espefuse.py -p burn_efuse DIS_USB_JTAG .. warning:: Burning eFuses is an irreversible operation, so please consider the above option before starting the process. OpenOCD can then be used:: openocd -c 'set ESP_RTOS hwtread; set ESP_FLASH_SIZE 0' -f board/esp32c6-ftdi.cfg Once OpenOCD is running, you can use GDB to connect to it and debug your application:: riscv-none-elf-gdb -x gdbinit nuttx whereas the content of the ``gdbinit`` file is:: target remote :3333 set remote hardware-watchpoint-limit 2 mon reset halt flushregs monitor reset halt thb nsh_main c .. note:: ``nuttx`` is the ELF file generated by the build process. Please note that ``CONFIG_DEBUG_SYMBOLS`` must be enabled in the ``menuconfig``. Please refer to :doc:`/quickstart/debugging` for more information about debugging techniques. Peripheral Support ================== The following list indicates the state of peripherals' support in NuttX: ============== ======= Peripheral Support ============== ======= ADC No AES No Bluetooth No CAN/TWAI Yes DMA Yes ECC No eFuse No GPIO Yes HMAC No I2C Yes I2S No Int. Temp. No LED No LED_PWM Yes MCPWM Yes Pulse Counter No RMT No RNG No RSA No RTC Yes SD/MMC No SDIO No SHA No SPI Yes SPIFLASH Yes Timers Yes UART Yes Watchdog Yes Wifi Yes XTS No ============== ======= Supported Boards ================ .. toctree:: :glob: :maxdepth: 1 boards/*/*