SAM7X Demo and PIT Spurious Interrupt Issue

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                 

SAM7X Demo and PIT Spurious Interrupt Issue

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

SAM7X Demo and PIT Spurious Interrupt Issue

Have you included a spurious interrupt handler? AT91C_BASE_AIC->AIC_SPU  = (int) AT91F_Spurious_handler;