ESP32-C3 DevKit

The ESP32-C3 DevKit is an entry-level development board equipped with either an ESP32-C3-WROOM-02 or an ESP32-C3-MINI-1. ESP32-C3-WROOM-02 and ESP32-C3-MINI-1 are SoMs based on the RISC-V ESP32-C3 CPU.

Most of the I/O pins are broken out to the pin headers on both sides for easy interfacing. Developers can either connect peripherals with jumper wires or mount ESP32-C3 DevKit on a breadboard.

ESP32-C3-DevKitC-02

ESP32-C3-DevKitM-1

Buttons and LEDs

Board Buttons

There are two buttons labeled Boot and RST. The RST button is not available to software. It pulls the chip enable line that doubles as a reset line.

The BOOT button is connected to IO9. On reset it is used as a strapping pin to determine whether the chip boots normally or into the serial bootloader. After reset, however, the BOOT button can be used for software input.

Board LEDs

There is one on-board LED that indicates the presence of power. Another WS2812 LED is connected to GPIO8 and is available for software.

Configurations

All of the configurations presented below can be tested by running the following commands:

$ ./tools/configure.sh esp32c3-generic:<config_name>
$ make flash ESPTOOL_PORT=/dev/ttyUSB0 -j

Where <config_name> is the name of board configuration you want to use, i.e.: nsh, buttons, wifi… Then use a serial console terminal like picocom configured to 115200 8N1.

coremark

This configuration sets the CoreMark benchmark up for running on the maximum number of cores for this system. It also enables some optimization flags and disables the NuttShell to get the best possible score.

Note

As the NSH is disabled, the application will start as soon as the system is turned on.

gpio

This is a test for the GPIO driver. It uses GPIO1 and GPIO2 as outputs and GPIO9 as an interrupt pin.

At the nsh, we can turn the outputs on and off with the following:

nsh> gpio -o 1 /dev/gpio0
nsh> gpio -o 1 /dev/gpio1

nsh> gpio -o 0 /dev/gpio0
nsh> gpio -o 0 /dev/gpio1

We can use the interrupt pin to send a signal when the interrupt fires:

nsh> gpio -w 14 /dev/gpio2

The pin is configured as a rising edge interrupt, so after issuing the above command, connect it to 3.3V.

nsh

Basic configuration to run the NuttShell (nsh).

ostest

This is the NuttX test at apps/testing/ostest that is run against all new architecture ports to assure a correct implementation of the OS.

pwm

This configuration demonstrates the use of PWM through a LED connected to GPIO2. To test it, just execute the pwm application:

nsh> pwm
pwm_main: starting output with frequency: 10000 duty: 00008000
pwm_main: stopping output

rmt

This configuration configures the transmitter and the receiver of the Remote Control Transceiver (RMT) peripheral on the ESP32-C3 using GPIOs 8 and 2, respectively. The RMT peripheral is better explained here, in the ESP-IDF documentation. The minimal data unit in the frame is called the RMT symbol, which is represented by rmt_item32_t in the driver:

The example rmtchar can be used to test the RMT peripheral. Connecting these pins externally to each other will make the transmitter send RMT items and demonstrates the usage of the RMT peripheral:

nsh> rmtchar

WS2812 addressable RGB LEDs

This same configuration enables the usage of the RMT peripheral and the example ws2812 to drive addressable RGB LEDs:

nsh> ws2812

Please note that this board contains an on-board WS2812 LED connected to GPIO8 and, by default, this config configures the RMT transmitter in the same pin.

rtc

This configuration demonstrates the use of the RTC driver through alarms. You can set an alarm, check its progress and receive a notification after it expires:

nsh> alarm 10
alarm_daemon started
alarm_daemon: Running
Opening /dev/rtc0
Alarm 0 set in 10 seconds
nsh> alarm -r
Opening /dev/rtc0
Alarm 0 is active with 10 seconds to expiration
nsh> alarm_daemon: alarm 0 received

spiflash

This config tests the external SPI that comes with the ESP32-C3 module connected through SPI1.

By default a SmartFS file system is selected. Once booted you can use the following commands to mount the file system:

nsh> mksmartfs /dev/smart0
nsh> mount -t smartfs /dev/smart0 /mnt

timer

This config test the general use purpose timers. It includes the 4 timers, adds driver support, registers the timers as devices and includes the timer example.

To test it, just run the following:

nsh> timer -d /dev/timerx

Where x in the timer instance.

usbconsole

This configuration tests the built-in USB-to-serial converter found in ESP32-C3 (revision 3). esptool can be used to check the version of the chip and if this feature is supported. Running esptool.py -p <port> chip_id should have Chip is ESP32-C3 (revision 3) in its output. When connecting the board a new device should appear, a /dev/ttyACMX on Linux or a /dev/cu.usbmodemXXX om macOS. This can be used to flash and monitor the device with the usual commands:

make download ESPTOOL_PORT=/dev/ttyACM0
minicom -D /dev/ttyACM0

watchdog

This configuration tests the watchdog timers. It includes the 2 MWDTS, adds driver support, registers the WDTs as devices and includes the watchdog example application.

To test it, just run the following command:

nsh> wdog -i /dev/watchdogX

Where X is the watchdog instance.