[Grbl_Esp32 Issue#222] Can’t upload firmware depending to what’s connected to D2 (MPCNCV1P2 Pinout)

Hi,

I’ve wired a prototype with MPCNCV1P2 pinout. I used level shifter modules with KSA1298 transistors (CMS marking J18). On the low V part of modules, there are 10K pullups.

After wiring i could not flash anymore via serial. Since my ESP module was solederd on my own shlied, i could not detach it. I searched a lot to find what wass messing the prog function and found.

It was because off the 10K resistor pullup on D2. I used instead a transistor basically wired (PNP) with success since is was not needing pullup. Flashing via serial was back.

I hope this could help somebody else, and maybe this could be put on “programming GRBL” wiki page : Avoid pullups on D2 and don’t wire modules you don’t kow how they are cabled..

Sincerely,

JP CIVADE