Pro mini and CP2012 uart not syncing

Hi folks
I got this Pro Mini from Ali Express

That took 18 days to get from China to Scotland.

I had got this CP2012 USB to uart serial converter thingymabob.

I had seen a video by that Indian man, oh what is his name. He says Hello Friends. He had similar boards, and just plugged the pins of the CP2012 board into the thru holes on the Pro mini. As they've got the serial pins along one edge. Tho my CP2012 board has 5v and 3.3v on those pins. The CP2012 chip got hot. So I pulled the board out of the USB. And Bent the 3.3v pin out of the way.

The cp2012 stays cool. red led is on that board. Power led and blinking led on the Pro mini.
I got the cp2012 drivers from Silicon labs. installed and my pc says working ok.

But Arduino IDE cant sync thru it. tries 10 times.

Oh yeah, I have some electronics experience. I have an UNO as well.

I tried searching for answers. couldn't find much.


Does CP2102 have a DTR pin? You need that connected to Promini DTR pin (which goes thru 0.1uF cap to Reset pin).
I can't open your link, maybe that will be easy to add, maybe not.

The pinout is different.

The pro mini pinout is:

Gnd (NC - sometimes grounded) +5v, TX, RX, DTR.

That adapter is:

3.3v Gnd +5v Tx, Rx, DTR

So the 3.3v pin should not be connected, and the gnd pin needs to be connected to the pin on the end. Make sure that you have it connected the right way around, not backwards.

You may have trashed the adapter, though, since you shorted it's 3.3v to ground. Check by disconnecting everythign else from the adapter, and connect Tx and Rx pins, then open serial monitor, send some text down it, and see if you get it back. If you don't, either the drivers are messed up , or you trashed the USB adapter by shorting 3.3v to ground.

I copied the URLs of the parts. But they seem to need to be pasted into a browser search engine, cant be clicked on. No idea why.
They have good photos of the boards on the original listings.

The Pro mini has


DTR RXD TXD +5v GND 3.3v Is the pins on the CP2012

I'll try connecting the TXD and RXD pins together and sending stuff from the serial monitor.
Not today tho. As I think it would just be rude words I would be sending.


(I can't open a lot of links, they are blocked here, so it's not you)

Well I switched my PC on today. I put a wire to TX RX on the Cp2012. It initialy didnt like it. I unplugged from USB, then in again. It was ok. I opened the serial monitor. Im not sure whats supposed to happen. I did get it to print what I wrote at the top, into the lower box.
Thought Id give the Pro Mini a try again. Just poking the programmers header pins thru the Pro minis thru holes.
I checked boards and ports in the IDE. Then uploaded blink to it. It worked. So I put the blink times at 100. So I havent broken it.
I had put another CP2012 on my watch list. think I’ll get one just in case.
I’ll solder the programming header pins to the Pro Mini as thats where the 5v is. I just placed the battery wires in the holes, to try it

Oh I was going to post a picture. But it needs a URL. Im so sick fed up with Photobucket and Flickr. There so fiddly to get to work with forums. That its not worth all the hassle for a grainy little photo. :confused:

So Reply, and Attach the picture instead. Then we can click it here to open it.