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SAM7X Demo and PIT Spurious Interrupt Issue

Posted by Çağlar Akyüz on January 31, 2007
I am using SAM7X Web demo with GCC. In addition to the default Demo settings, I added an SPI interrupt and vApplicationTickHook function. My problem is that vApplicationTickHook function is called (sometimes) accidentally(i.e. spurious interrupt). It should be called within each 1 msec. It is called generally but sometimes period changes to ~ 40 microsec and then 1 msec again. Following is the what I see on my scope.(I'm toggling a pin in vApplicationTickHook)

--------- ---------- ---------
| | | | |
| | | | |
| | | | |
---------- ---- ---------
1msec 1mes 1mes 40u 1msec 1mesc ..................

I relized that if I send less data from Ethernet, occurence of these abnormal pulses decreases,also. I wonder if anybody has faced this kind of behaviour.

Best regards,
Caglar Akyuz

RE: SAM7X Demo and PIT Spurious Interrupt Iss

Posted by Çağlar Akyüz on January 31, 2007
I'm sorry for the last message because that scope output was not what I intended to draw. Let me clarify :

1 msec High, 1msec Low, 1msec High, 40 microsecond low, 1msec High...and goes like that.

Sorry for the inconvenience.

Caglar Akyuz

RE: SAM7X Demo and PIT Spurious Interrupt Iss

Posted by embeddedc on January 31, 2007
Have you included a spurious interrupt handler?

AT91C_BASE_AIC->AIC_SPU = (int) AT91F_Spurious_handler;

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