wiki/en/hardware-programmer-ch341a-voltage-fix.md

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CH341A Programmer

Fixing high voltage bug

Early versions, prior ver. 1.7, of the cheap and popular CH341A Mini Programmer have a nasty bug where voltage levels on data lines remain at 5V despite the programmer being set to 3.3V with the jumper.

@ddemos1963 came out with an interesting hack to fix the issue in an efficient and artsy way.

Here's what you do.

Sever the connection between between 5V power line and the CH341A chip. With a sharp utility knife, cut the trace on the back of the programmer board.

Connect 3.3v output leg of the voltage regulator to pin 9 of CH341A IC bridging it to a corresponding trace at a nerby capacitor.

Restore power to the chip re-routing 3.3V voltage from 3v3 pin to pin 28 of CH341A IC through 5V pin connector on the header.

Software

• SNANDer or this fork
• microsnander from OpenIPC
• ch341prog
• flashrom
• DIY BCQ CH341A forum (Chinese, use Chrome automatic translation)
• CH341A Programmer (Russian, use Chrome automatic translation)