FTDI won't upload to 3.3V ProMini

Other Miscellaneous
1

Hi.

I have an ISL29125 board and a 3.3 V ProMini. I cut and re-soldered the jumper on a 5 V FTDI so I could use it with this setup. I checked the FTDI in Windows 10 Device Manager and it thinks it’s working properly. However, I can’t upload the test code for this device, or any code, to the 3.3 V ProMini. When I tried uploading the same code with a 5 V FTDI and a 5 V ProMini (without connecting the ISL29125 to this 5 V board, of course), the code uploaded with no problem. Windows tries to assign COM8 for the 3.3 V FTDI and COM7 for the 5 V FTDI, but when I try to upload through the 3.3 V FTDI the IDE error messages just say that it’s not synced and can’t upload. no matter what port I try to use.

Am I doing something wrong here? Is the converted 3.3 FTDI somehow not working even though Device Manager thinks it is?? Suggestions? Help?

2

Windows released an update a while ago that broke the drivers; try re-installing them https://learn.sparkfun.com/tutorials/ho … rivers/all and see how that goes, and maybe afterward try using the 3.3v with a different 3.3v device and see if it is able to communicate

3

Well, my Windows think that the best drivers for this device are already installed. When I tried the FTDI setup.exe file, it wouldn’t install anything else because it said I already had the best drivers installed. As I said before, the 5 V FTDI works perfectly well. Why should the 3.3 V be any different? It is true, as I said before, that I’m using a “5 V” FTDI where I changed the jumper for 3.3 V operation. I have carefully checked the resistance across the original 5 V jumper to make sure that connection is broken.