Yet Another USB Programmer / USB to TTL serial converter.
Yes there are lots of them out in the market utilizing different converter chips. What we did with ours was take the CH340 chip added couple of transistors and few  passive components and made it dual purpose adapter. 1 is a basic USB to serial TTL converter with all RS232 pins routed to the sides.  2 we routed selective Rx/Tx/DTR pins to 6 pin header for standard pinout  used in various programming and control uses.  3 with couple transistors and 2x3 header we made turned that ports for ESP specific programmer that will put the microcontroller automatically in programming mode.

The board can be populated with CH340G needing additional 12MHz crystal or CH340C .


Additionally 3.3v regulator provided 750mA of current selectable between it and 5.0V to the target board if needed. If jumper is not placed target board will need to be powered by external power source.







 

Features of the  board

o     LCh340c or CH340G controller    
o     LED indicators
        o Power
        o   Target
o   Standard 6 pin header for programming    

o   All RS232 signals from CH340 chip routed to outer headers   

o   2x3 header for ESP programing with auto reset and programing mode   

o    mini USB connector