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Reset problem with MKL26Z

Question asked by John Brown on Nov 5, 2016
Latest reply on Nov 5, 2016 by John Brown

Reset problem witk MKL26Z

 

My custom board will run fine if the P&E Multilink is connected and I execute Flash from file, and it will continue to run if I then disconnect the SWD header(probably not advisable, but proved a point). However, it refuses to run if I then power cycle it. The reset pin still measures 3V3, and there do not appear to be any pulses on the reset pin according to my scope.

The original design had a 100nF cap to ground, and a 10k to 3V3, but I removed the cap some time ago, as I was having problems, which later turned out to be the result of P&E numbering their headers the wrong way round, which had confused our hardware designer.

Would be grateful for any insight.

 

I have now tried replacing the 100nF cap, but to no avail. I don't think the reset pin on the chip is the problem, as it does reset the chip if pulled low(it kills the running code, anyway), but the processor won't start up again. I have added a small piece of code to turn on an LED, that happens before even initializing the PLL, bit it doesn't even get that far.

I'm at a loss to know how to debug this, as when the debugging tool is connected, it works perfectly!

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