CH340C-Module

This CH340C-Module is a specialized ESP32 programmer PCB that simplifies the programming process by incorporating auto-programming functionality. This means there's no need for manual interaction with the ESP32 during programming, such as pressing buttons on the board. Additionally, it supports Power Delivery (PD), allowing the attached ESP32 to be powered from a PD source at 5V.

Visual Overview

Key Features

• Compact Design: The module is designed to occupy minimal space, making it ideal for streamlined setups.
• Power Delivery Support: Compatible with Power Delivery, enabling the ESP32 to run directly from a 5V PD source.
• USB-C Connectivity: Utilizes a USB-C connection for modern, reversible, and reliable connectivity.
• Auto-Programming: Simplifies the programming process by eliminating the need for manual button presses on the ESP32 during programming.

Schematic

Part List

The following table contains all the parts required for the CH340C-Module, along with their corresponding printed names. The parts are listed in the recommended order of soldering.

Reference	Part Name	Description
J1	CQ-USB-C16PSMT01	16 Pin female USB C connector
U2	CH340C	Programming IC, SOP-16 package
R1	0603-5.1k	Resistor, 0603 sized, 5.1 kilo Ohm
R2	0603-5.1k	Resistor, 0603 sized, 5.1 kilo Ohm
C1	0603-100nF	Capacitor, 0603 sized, 100 nano Farad
C2	0603-4.7uF	Capacitor, 0603 sized, 4.7 micro Farad
JP1	Jumper	short: mid (VCC) with left/inner (3V3) or right/outer (5V)
U4	AO3400	N-Channel Mosfet, SOT-23 package
U3	AO3400	N-Channel Mosfet, SOT-23 package
U1	AMS1117 3.3V	5V to 3.3V Voltage regulator, SOT-223 package

Libraries / Footprints used

• https://github.com/sparkfun/SparkFun_Eagle_Settings/blob/main/ulp/exp-lbrs.ulp
• https://snapeda.com/parts/AMS1117/Advanced+Monolithic+Systems/view-part/
• https://snapeda.com/parts/AO3400/Alpha+%2526+Omega+Semiconductor+Inc./view-part/
• https://snapeda.com/parts/CH340C/WCH/view-part/
• https://snapeda.com/parts/CQ-USB-C16PSMT01/Shenzen%20Chuangqin%20Technology/view-part/?ref=search&t=CQ-USB-C16PSMT01
• https://github.com/epukaza/eagle-libraries/blob/master/eagle-ltspice.lbr
• https://github.com/sparkfun/SparkFun-Eagle-Libraries/blob/main/SparkFun-Jumpers.lbr

Driver

https://wch.cn/download/CH341SER_ZIP.html

Key Takeaways

• The CH340C can be powered with 3.3V or 5V. The input Voltage translates to its TX voltage and 5V is too high for e.g. an esp32, so it gets powered with 3.3V
• The 3V pin of the CH340C needs to be connected to GND with a 100nF capacitor, else it will not work and not show up in device manager
• Connecting it with wrong polarity (5V and GND) gets the chip hot quickly, but doesn't break it when cutting the power off soon (like 20 seconds)
• The minimum circuit, only to check if a CH340C ic is functional, consists of a usb port with (5V, D-, D+, GND) connected to the CH340C as well as the said 100nF capacitor from its 3V pin to GND
• The capacitor (C2) between EN and GND needs to be high enough, else the auto reset will not work. 100nF was too little, so the IDE was stuck at Hard resetting via RTS pin... and the module had to be plugged out and in again manually. Increasing the capacitance to 4.7uF solved this and the auto reset works fine with that.

Sponsorship - PCBWay

The physical PCB's and stencil are sponsored by PCBWay.
Overall i am very satisfied with the quality of the pcb's, especially with

• the matte surface finish
• the cover of the vias, which almost feel like plugged, so there is no way to accidentally put solder in there to cause a short circuit
• the traces, which are covered better than other manufacturers do and cannot be brushed/scraped away easily. Big plus for that

One thing i missed was clearer texts (white) on the pcb's, but printing those in good quality, especially sized at 0.6mm, can be challenging.
I am very pleased to get these sponsored by PCBWay and can recommend their service, especially for the high quality you get and the huge amount of configurable settings.

Video preview

Recording.2023-12-08.222351.mp4