[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re(2): Re(2): External DMA interrupts



Hi Per.
>
>Do you get the data out on the external DMA channel as expected ?

Yes.
>
>
>One reason could be if you enable the external DMA interrupt (in the 
>interrupt mask) before you start the external DMA channel. Possibly there
>is also a small latency after giving the start command to the external
>DMA 
>channel until it is actually started.

Yes, i had the external DMA interrupt enabled *before* I started the
external DMA. I thought that the interrupt will be triggered when the run
bit will be cleared, not when the run bit *is* clear. After this change in
the code I receive only one interrupt, the expected one. 
One final question : If I enable the interrupt after starting the channel,
what happend when DREQ ist still high ? Is it possible to loose an
interrupt because the transfer has been started/finished (e.g. burst mode,
only one burst) before I enable the interrupt ? 
>
>I hope this helps

Yes, thanks a lot !

	Arne Bockholdt
>

Dipl. Inform. Arne Bockholdt
REA Elektronik GmbH
Teichwiesenstr. 1
64367 Mühltal-Waschenbach
Tel. +49 (0) 6154 / 638-115, Fax -195
ABockholdt@xxxxxxx.de