ESP32 Modules with CH340 USB Chips Running at 5V instead of 3.3v on Tx/Rx?
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- เผยแพร่เมื่อ 29 ก.ย. 2024
- These ESP32 modules have a CH340 USB chip configured to run at 5v instead of 3.3v so I'm fixing these. Some modules also have weird wifi signal strength issues but I can't seem to improve that on all of them.
Discussion on ESP32 with CH340 issues community.home...
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So my RX is 5V as well, while the TX is 3.3v
This is when powering from USB.
Powering from 3V3, RX is 2.6V and TX is 3.3V.
If someone can tell if the RX dropping that low is to be expected while not transmitting, please let me know.
is that while applying 3.3 V to the Vin pin? and is that with a CH 340 chip?
I think the module vin pin is intended to take higher than 3.3 V so the onboard regulator can bring it down to 3.3 but I’m not sure if the regulator on these modules just passes through 3.3 in to out without a drop out.
having 2.6 on the Rx pin is definitely not normal and it’s around the bottom threshold for detecting logic high which I think is 2.65 V when running at 3.3 V so it definitely needs to be run differently to get that back to 3.3 V.
I usually buy the versions that use an external antenna so that I have some freedom to get better signal coverage.
Nice find, clever fix, interesting mystery...
Very good explanation. USB IC provides the level shifting when it is connected to a 5V USB port. Why CH340 is connected to 5V? Doesn't cost anything, in fact they could have saved those 2 resistors. About the RSSI, would like to see the difference between the original modules from ESSPRESSIF and the clones.