An Even Simpler Fix When Upload Fails

  • If you are having trouble uploading your firmware, a low value non polarized capacitor on the RST line might help. I used a 0.068 uF ceramic cap because it was close by, but 0.1 uF is more standard and might be easier to find.

    If you connect one side to RST, the other can be connected to BAT, 3.3V, or GND.

    alt text

    You can't go wrong if you use a non polarized capacitor like shown here, but be super careful if you use a polarized capacitor. The polarity of the capacitor is opposite if you use RST/GND vs (RST/3.3 or RST/BAT). You can ruin the capacitor if you get it backwards. Polarized caps get damaged and become conductive if they are reversed. If you reverse one, best to throw it away.

    It doesn't seem intuitive to connect it to BAT or 3.3 instead of GND, but it basically does the same thing. The reason why I like BAT is because it's close to RST on the connector. I just plug it in, like a jumper whenever I need to program.

  • 0_1519712214333_coreUploadFails.png

  • @m5stack

    You might be missing the point of my post. I did see your solution on the other thread. The reason why I'm avoiding your solution is that it requires some detailed SMT soldering. Many people don't have the ability, equipment, or components to do SMT rework. I do have an air rework station, but I still avoid doing SMT rework whenever I can.

    I'm still using my original solution (plugging a 0.1uF non polarized ceramic capacitor in the connector between RST and BAT) and it's worked perfectly for me. Do you see any problem with what I am doing? You just posted some pictures without text so I don't really know what your point is.

  • @scotts Hi Scott,

    I'm pretty sure that was just added as another possible fix.... without intending to suggest that there was anything wrong with your solution.... indeed I am about to follow your suggestion and add a ceramic cap to a proto board.

    Here's another approach again... very creative and neat. This is from the highly recommended macsbug website: