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Board no longer powers up #28
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can you still communicate with the controller via the SWD interface (e.g. still program it?), if powered only via the SWD interface? |
Maybe also check with magnification that there is no bent pin/short or any other metal flicker sticking somewhere. |
I wonder if BEMF could have kill it. Because when I drive the motor from the output fast enough, the MCU resets. @Quas7 Do you have idea why is it restarting? The input voltage is stable and current is never reversed. - Hmm, maybe that's the key, because I think the board have reverse polarity protection diode. So if that diode doesn't allow the current to flow in reverse, the internal voltage will rise high. Though, I would expect the linear regulator to heatup, and no MCU reset. ....Hah, while writing this I run it with a drill for a bit longer, while it was reseting. It seems the A4950 didn't handle BEMF. Mosfet are shorted and it is drawing 0.4A continuously now. Bummer. Anyway, I still don't udnerstand why it was resetting. I guess for now I am going to stick with MKS42B which doesn't have reverse polarity diode. I also put clamping diode on supply lines to protect for overvoltage. |
The damage was due to lack of protection against BEMF and reverse polarity protection not allowing to sink current back to power supply. |
I'm afraid I fried my board. I have been very careful to power down before making any connection or switch changes. Now the green LED no longer turns on. Just on the off chance that I can resurrect this thing, Has anyone else saved one of these?
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