128 lines
4.3 KiB
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128 lines
4.3 KiB
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==================
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Espressif ESP32-C3
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==================
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The ESP32-C3 is an ultra-low-power and highly integrated SoC with a RISC-V
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core and supports 2.4 GHz Wi-Fi and Bluetooth Low Energy.
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* Address Space
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- 800 KB of internal memory address space accessed from the instruction bus
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- 560 KB of internal memory address space accessed from the data bus
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- 1016 KB of peripheral address space
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- 8 MB of external memory virtual address space accessed from the instruction bus
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- 8 MB of external memory virtual address space accessed from the data bus
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- 480 KB of internal DMA address space
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* Internal Memory
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- 384 KB ROM
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- 400 KB SRAM (16 KB can be configured as Cache)
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- 8 KB of SRAM in RTC
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* External Memory
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- Up to 16 MB of external flash
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* Peripherals
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- 35 peripherals
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* GDMA
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- 7 modules are capable of DMA operations.
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ESP32-C3 Toolchain
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==================
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A generic RISC-V toolchain can be used to build ESP32-C3 projects.
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SiFive's toolchain can be downloaded from: https://static.dev.sifive.com/dev-tools/riscv64-unknown-elf-gcc-8.3.0-2019.08.0-x86_64-linux-ubuntu14.tar.gz
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Second stage bootloader and partition table
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===========================================
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The NuttX port for now relies on IDF's second stage bootloader to carry on some hardware
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initializations. The binaries for the bootloader and the partition table can be found in
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this repository: https://github.com/espressif/esp-nuttx-bootloader
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That repository contains a dummy IDF project that's used to build the bootloader and
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partition table, these are then presented as Github assets and can be downloaded
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from: https://github.com/espressif/esp-nuttx-bootloader/releases
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Download ``bootloader-esp32c3.bin`` and ``partition-table-esp32c3.bin`` and place them
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in a folder, the path to this folder will be used later to program them. This
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can be: ``../esp-bins``
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Building and flashing
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=====================
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First make sure that ``esptool.py`` is installed. This tool is used to convert
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the ELF to a compatible ESP32 image and to flash the image into the board.
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It can be installed with: ``pip install esptool``.
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Configure the NUttX project: ``./tools/configure.sh esp32c3-devkit:nsh``
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Run ``make`` to build the project. Note that the conversion mentioned above is
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included in the build process.
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The `esptool.py` command to flash all the binaries is::
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esptool.py --chip esp32c3 --port /dev/ttyUSBXX --baud 921600 write_flash 0x0 bootloader.bin 0x8000 partition-table.bin 0x10000 nuttx.bin
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However, this is also included in the build process and we can build and flash with::
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make download ESPTOOL_PORT=<port> ESPTOOL_BINDIR=../esp-bins
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Where ``<port>`` is typically ``/dev/ttyUSB0`` or similar and ``../esp-bins`` is
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the path to the folder containing the bootloader and the partition table
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for the ESP32-C3 as explained above.
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Note that this step is required only one time. Once the bootloader and partition
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table are flashed, we don't need to flash them again. So subsequent builds
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would just require: ``make download ESPTOOL_PORT=/dev/ttyUSBXX``
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Debugging with OpenOCD
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======================
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Download and build OpenOCD from Espressif, that can be found in
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https://github.com/espressif/openocd-esp32
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If you have an ESP32-C3 ECO3, no external JTAG is required to debug, the ESP32-C3
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integrates a USB-to-JTAG adapter.
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OpenOCD can then be used::
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openocd -c 'set ESP_RTOS none' -f board/esp32c3-builtin.cfg
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For versions prior to ESP32-C3 ECO3, an external JTAG adapter is needed.
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It can be connected as follows::
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TMS -> GPIO4
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TDI -> GPIO5
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TCK -> GPIO6
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TDO -> GPIO7
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Furthermore, an efuse needs to be burnt to be able to debug::
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espefuse.py -p <port> burn_efuse DIS_USB_JTAG
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OpenOCD can then be used::
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openocd -c 'set ESP_RTOS none' -f board/esp32c3-ftdi.cfg
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Peripheral Support
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==================
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The following list indicates the state of peripherals' support in NuttX:
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========== ======= =====
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Peripheral Support NOTES
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========== ======= =====
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GPIO Yes
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UART Yes
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SPI Yes
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I2C Yes
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DMA Yes
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Wifi Yes
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SPIFLASH Yes
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Timers Yes
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Watchdog Yes
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RTC Yes
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RNG Yes
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AES Yes
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eFuse Yes
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ADC Yes
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Bluetooth Yes
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LED_PWM Yes
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SHA Yes
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RSA Yes
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========== ======= =====
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