1. If external power supply is required, just connect the external power supply + level to the 5V position and GND to the negative pole. (Supports 3.3-6V power supply). 2. Remember, you cannot connect USB when connecting external power supply. You can only choose one between USB and external power supply. 3. Enter download mode: long the BOOT key of ESP32C3, then the RESET key, release the RESET key, and then release the BOOT key. At this time, ESP32C3 enter download mode. 4. You need to re-enter download mode every time you connect. Sometimes the port be unstable and disconnected after pressing it once. You can judge it by the port recognition sound. 5. ESP32C3 is optimized for IoT and wearable technology applications. It is a high-performance, low-power development board with both cost-effectiveness and advanced functions. It is suitable for a wide range of low-power IoT projects. Powerful CPU:ESP32-C3,32-bit RISC-V single-core processor, running up to 160 MHz WiFi:802.11b/g protocol, 2.4GhHz,support Station mode, SoftAP mode, SoftAP+Station mode, hybrid mode Bluetooth:Bluetooth 5.0 Due to different batches, the product appearance and printed text , but it not affect the use. Colour:Black Material:Plastic Package Contents: 2 * unsoldered development boards 4 * pin headers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.