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MCF52259 Spurious interrupt, help tracking it down

Question asked by FridgeFreezer on Jan 13, 2011
Latest reply on Jan 21, 2011 by TomE

A bit cheeky as I've already posted in the CW section but not had much luck:


We are using an MCF52259 on our own PCB, CW7.2. We have interrupts and ISR's set up for:



UART0,1 & 2


PIT0,1 (as fixed interval timers)

DTIM0,1,2,3 (variable freq, driving stepper motors)

RTC (seconds)


All seem to be working correctly, but at seemingly random intervals we are getting spurious interrupts. There seems to be no pattern to it - we can shove data up the UARTS, drive motors, leave the thing idle, whatever and sometimes it is fine for hours but other times it hits the spurious ISR in seconds. In our current prototype we are not using UART2, but I have left the ISR in place doing a dummy read of the Rx buffer and clearing any flags.


I have read MJBSwitzerland's excellent post about spurious interrupts, but nothing contained in it seems to have helped.


Does anyone have any wisdom on how to track down the source of the problem?