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LPC43xx Timer Interrupt Issue

Question asked by Sam Crosse on Jun 13, 2018
Latest reply on Jun 18, 2018 by Hui_Ma

I have written some pulse control software for LPC4337 @ 200MHz.  Some code is in M0 but of no consequence.  Most of the code is in M4.

 

M4:-

It uses 4 timers (0-3), and 4 Match compares per timer.  1us timer clock

 

The Matches generate interrupts, and those interrupts check the IR[] to find the source, clear that bit, and manually control an individual GPIO output.

 

Something strange is happening.  At random intervals (anywhere from 18 seconds to 20 mins), Timer 2 Match 3 INT gets missed! ALL OTHER TIMER INTS ARE OK.  It will miss a single INT, then next time the compare register is set the INT works fine.  

 

I cannot explain it, all INTs use similar code, and the code that sets the compare registers is similar.

So, Timer 0 Match 0-3 OK

Timer 1 Match 0-3 OK

Timer 2 Match 0 OK, 1 OK, 2 OK, 3 Glitches (IR[2] & 0x08)

Timer 3 Match 0-3 OK

 

 

 

SCT is unused

 

-Sam

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