This module is pin compatible with ESP-01M.
There are two different versions of this module:
- C3FN4 with 4Mb flash
- C3-2M with 2Mb flash. This version is not recommended for Tasmota due to low flash space.
To put the module in flash mode pull GPIO9 low before powering on. GPIO8 is already pulled high.
Flash using Tasmota Web Installer using Tasmota32c3 4M Flash option.
esptool.py --chip esp32c3 --baud 460800 --before default_reset --after hard_reset write_flash -z --flash_mode dout --flash_freq 40m --flash_size detect 0x0000 bootloader_dout_40m.bin 0x8000 partitions.bin 0xe000 boot_app0.bin 0x10000 tasmota32c3.bin
For normal operation connect EN to VCC (pull high) to enable the C3 chip. GPIO9 has an internal pullup and it needs to be high on power up for the module to boot so try and avoid that pin similar to GPIO0 on ESP8266.
ESP32’s are power hungry on boot and the USB to serial adapter might not be able to provide enough power for that. Use a stable 3.3v power supply that can supply more than 500 mA