I have a system that uses EIRQ2 on GPIO4 to service an interrupt from an external device. Overall the sytsem operates correctly, except when a powered reset is activated, by pressing the reset button. Occasionally the system does not restart correctly and flashes the yellow LED to indicate the fault.
I have checked out what is happening and it seems that at times when the reset pressed the external device is in a state where it is holding the Interrupt active low. This seems to generate an interrupt during the initial boot process, and the unit fails to start.
A previous iteration of the board had the external device interrupt connected to EIRQ3, but this did not seem to cause the problem.
Has anyone any info on how the interrupt system is initially set up and why GPIO4 being held low would cause this type of problem?