Using Alpha Blending Mixer Megacore with Nios II

Hello,

I've got a problem interfacing Nios II and the VIP suite, especially with the Alpha Blending Mixer Megacore.

My problem is that I can't stop the mixer. Basically, I set the Go bit to '0' and then poll the status register to check the result. But it never goes down.

Here is my function which is used to start and stop the megacore:

alt_u32 ALT_VIP_FRAME_READER_GOBIT(alt_u32 vipBaseAddress, alt_u32 go){

alt_u32 status ;

alt_u32 watchdog = 0x00;

do{

IOWR(vipBaseAddress, ALT_VIP_FRAME_READER_CONTROL_REG, go);

status = IORD(vipBaseAddress, ALT_VIP_FRAME_READER_STATUS_REG);

watchdog++;

}

while( (status != go) && (watchdog != TIMEOUT) );

return status;

}

Do you see anything wrong with that method?

Regards,

Lionel.