This project is a simple board to program and debug ESP32 chip using a USB-C port.
The core is a CP2104 USB-to-Serial converter and it uses the RTS and DTS signals to reset the MCU in boot mode for programming.
The programming post is a 6-pins JST PH SMT connector, with the following mapping:
| Pin # | Signal Name | Note |
|---|---|---|
| 1 | +3.3V | |
| 2 | GND | |
| 3 | TX | From host to target |
| 4 | RX | From target to host |
| 5 | RESET | The board has a button shorting this line to GND |
| 6 | BOOT0 | Should be connected directly to GPIO0 |
You can find the BOM on Octopart via this link.
| Reference Designator | Manufacturer | Product Number | Description | Quantity | Value | Tolerance | Rating | Package |
|---|---|---|---|---|---|---|---|---|
| U1 | Diodes Inc. | AP2112K-3.3 | 3.3V 600mA LDO w/ EN | 1 | SOT25 | |||
| U2 | Silicon Labs | CP2104 | USB-to-UART Bridge | 1 | QFN-24 | |||
| ESD1 | ON Semiconductor | ESD5B5.0ST1G | TVS Diode 5V | 1 | SOD523 | |||
| ESD2 | LittelFuse | SP3401 | TVS Diode Arrays for USB | 1 | JEDEC MO-229 | |||
| D1 | Würth Elektronik | 150060RS75000 | Red LED | 1 | 0603 | |||
| D2 | Würth Elektronik | 150060GS75000 | Green LED | 1 | 0603 | |||
| D3 | Würth Elektronik | 150060BS75000 | Blue LED | 1 | 0603 | |||
| Q1 | Diodes Inc. | MMDT2222A | Dual Small Signal NPN Transistor | 1 | SOT363 | |||
| C1, C2, C4 | 10µF, 10V SMT Ceramic Capacitor | 3 | 10µF | ≤±20% | ≥10V | 0603 | ||
| C3 | 1µF, 10V SMT Ceramic Capacitor | 1 | 1µF | ≤±20% | ≥10V | 0603 | ||
| C5* | 4.7µF, 10V SMT Ceramic Capacitor | 1 | 4.7µF | ≤±20% | ≥10V | 0603 | ||
| R1, R2 | 5.1kΩ SMT Resistor | 2 | 5.1kΩ | ≤±1% | 0603 | |||
| R3 | 100kΩ SMT Resistor | 1 | 100kΩ | ≤±5% | 0603 | |||
| R4, R5, R6 | 10kΩ SMT Resistor | 3 | 10kΩ | ≤±5% | 0603 | |||
| R7 | 330Ω | 1 | 330Ω | ≤±5% | 0603 | |||
| R8 | 120Ω | 1 | 120Ω | ≤±5% | 0603 | |||
| R9 | 91Ω | 1 | 91Ω | ≤±5% | 0603 | |||
| J1 | Molex | 105450-0101 | USB-C SMT Connector | 1 | ||||
| J2 | JST Inc. | S6B-PH-SM4-TB(LF)(SN) | 6-Pins SMT JST PH Connector | 1 |
Notes:
- *
C5is only required to modify the device OTP memory. It can be ignored.- Red LED is for power, Blue LED is for host RX, Green LED is for host TX.