In the interrupt routine you need to clear the interrupt.
Check to see that you are doing that.

George

Hello all,

I am monica from germany.I am using NIOS in cyclone FPGA.I have problem
with PIO interrupts.
Environment details

Quartus Software : version 4.2 build 178 01/19/2005 SJ full version
Nios software    : version 1.1.0 build 137
FPGA             : Altera cyclone

I have a input signal which should generate interrupt on every rising
edge.So I have used a PIO to capture the signal and generate the IRQ
for every rising edge.

PIO settings :
width : 1bit
direction : input only
Edge capture reg
synchronously capture : yes
rising edge :yes
generate irq : yes
edge : yes

The software hangs at
"alt_irq_register(TEST_CONTINUE_PIO_IRQ,(void
*)&global_flag,&intr_timer);"

However software works fine,If I change the PIO settings to

width : 1bit
direction : input only
Edge capture reg
synchronously capture : yes
rising edge :yes
generate irq : yes
level : yes

I am trying to find out what might be causing my software hang if I use
"edge" instead of "level".

Did anybody face this sort of wierd behaviour? or is this a bug in
Quartus software?

I have already wasted lot of time to find out a solution for this
problem.

I will be obliged if anybody can throw some light on this issue.

Thanking you,
Monica Dsouza