The IFR in TMS320C6670 can not be set

Dear all,

When debug with TMS320C6670, I found the event in EVTFLAG0 has been set, but the IFR can not be set. Refer to the exhibit.

Enviorment : use TMDSEVM6670LE, use on board emulator, just connect the core and load the GEL file(attached).

1.First, check the core register

2.INT8 not enable，use INT8 for test，then check INTMUX2(view memory at 0x01800108)

3.INT8 map to event8，check if event8 has occured (the bit is set/clr)，check EVTFLAG0(view memory at 0x01800000)

4.EF8 is '0'，write 0x00000100 to EVTSET0(0x01800020)，manual set EF8.

5.Check core register, IF8 not set

I also try other INT(4-15) with the corresponding  bit in IER set(the interrupt is enabled), and then manually set the event.

The IFR can not set either.

What's wrong with it?

Any advice will be helpful.

Best regards!