Edge triggered external interrupt MPC8260.

[supriyoganguly]

Hello,

We are user of MPC8260.We are using IRQ4 interrupt line in edge triggered mode.The core is getting the interrupt.But when I try to read SIVEC register, it shows '0'. I am not getting proper value in SIVEC.

[r8070z]

Have a great day,

There can be spurious interrupt or software error. Spurious means that interrupt source is disappear before SIVEC reading (for example due to floating IRQn configured for level mode). To test your IQR4 handler mask all interrupt sources except IRQ4 in SIMR and write all ‘1’ to SIPNR before enable external interrupt in MSR. If in this case you still get interrupt with SIVEC=0 then there is software error. Check that IRQ4 really set for edge triggered mode and that interrupt handler does not mask IRQ4 bit in SIMR or clear pending IRQ4 bit in SIPNR  before SIVEC reading. Short but comprehensive description of the MPC8260 interrupt controller operation you can find in training document https://www.nxp.com/docs/en/supporting-information/TPQ2CH12.pdf

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