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EAGLE component library
USB to 3.3V-5V serial TTL adapter
This post is about experimental USB to 3.3V/5V serial TTL adapter which we build recently to work with both 5V and 3.3V MCUs. This project is mainly based on CH340G seral-USB chip. CH340G is cheap and commonly available serial-USB convert IC and now it's commonly found on Chinese versions of Arduino development boards.
is another possible alternative for this kind of project, but we drop it because of its famous
device driver base chip locking issues
. Also compare with FT232, CH340G is cheap, commonly available and simple to construct with minimum number of components.
In this module we incorporate 5V/3.3V voltage selector switch to avoid interface matching issues due to different voltage levels of main-board/MCU and serial TTL adapter.
Prototype version of CH340G base USB to serial adapter.
In prototyping stages we use CH340G with breadboard by using SO-16 to DIP16 adapter and supplied PCB is also based on using the same adapter. Except CH340G all the other components in this project are standard through-hole type components and may not need any special soldering techniques for construction.
In prototyping we test this adapter successfully with several MCUs which including
. The device driver for CH340G is available to download at
Project Related Downloads
Schematic and PCB design related to USB 3.3V/5V serial TTL adapter
CH340G - Technical manual for USB to serial IC
FT232 - USB UART IC
help on how to format text
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