DMA-controller doesn't generate an interrupt after changing the transaction type once

Hello Pillemann (sounds german to me),

I do not check how the transfer ends. I set up the dma controller to end when the length register reaches zero and the driver checks that length is a integer multiple of the transfer type's length in bytes (ie. 4 or 8 in my case).

I watched the length register in signal tap. It always reaches zero even if no interrupt is generated.

I fixed the problem in not changing the transfer type. Every transfer is double word. That doubled the throughput, too.

I normally do not reset the go bit but I tried to - without success. Only a reset before changing the transfer type soluted the problem. But the reset operation reduced the throughput significantly.

My driver generates a timeout if no interrupt occures. I will check the status register after a timeout and post it.

I'm using Quartus 10.0 SP1.

Regards from Hamburg,

Frederik