121 lines
4.7 KiB
Plaintext
121 lines
4.7 KiB
Plaintext
README for the Espressif ESP32-C3 DevKit
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=======================================
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The ESP32-C3 DevKit is an entry-level development board equipped with either
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an ESP32-C3-WROOM-02 or an ESP32-C3-MINI-1.
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ESP32-C3-WROOM-02 and ESP32-C3-MINI-1 are SoMs based on the RISC-V ESP32-C3 CPU.
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Most of the I/O pins are broken out to the pin headers on both sides for easy
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interfacing. Developers can either connect peripherals with jumper wires or
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mount ESP32-C3 DevKit on a breadboard.
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ESP32-C3 Features
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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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The configurations provided are using a generic RISC-V toolchain to build ESP32-C3 projects.
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It 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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Buttons and LEDs
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================
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Buttons
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-------
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There are two buttons labeled Boot and RST. The RST button is not available
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to software. It pulls the chip enable line that doubles as a reset line.
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The BOOT button is connected to IO9. On reset it is used as a strapping
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pin to determine whether the chip boots normally or into the serial
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bootloader. After reset, however, the BOOT button can be used for software
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input.
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LEDs
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----
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There is one on-board LED that indicates the presence of power.
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Another WS2812 LED is connected to GPIO8 and is available for software.
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Configurations
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==============
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nsh
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---
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Basic configuration to run the NuttShell (nsh).
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gpio
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____
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This is a test for the GPIO driver. It uses GPIO1 and GPIO2 as outputs and
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GPIO9 as an interrupt pin.
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At the nsh, we can turn the outputs on and off with the following:
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nsh> gpio -o 1 /dev/gpout0
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nsh> gpio -o 1 /dev/gpout1
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nsh> gpio -o 0 /dev/gpout0
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nsh> gpio -o 0 /dev/gpout1
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We can use the interrupt pin to send a signal when the interrupt fires:
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nsh> gpio -w 14 /dev/gpint2
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The pin is configured as a rising edge interrupt, so after issuing the
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above command, connect it to 3.3V.
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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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If the project isn't clean, please run `make distclean` before configure.sh or
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run configure.sh with -E option.
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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 `esptool.py --chip esp32c3
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--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 use build and flash with:
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`make download ESPTOOL_PORT=/dev/ttyUSBXX ESPTOOL_BINDIR=../esp-bins`
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The "../esp-bins" path is the path to the folder containing the bootloader and the
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partition table 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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