AW: DMA transfer over PCI

["Heiner, Andreas" <HeinerA@Becker.de>]

Hi Dinesh,

Please take a look into the spec first to understand the basics of the bus.

1. The PCI bus is a multi master bus.
2. The minimum transfer size is one byte!
3. There is no central DMA engine available.

This means:

You can only transmit data over the PCI bus by DMA if your card is capable
to initiate a bus master access. The minimum size depends on the
implementation if this DMA engine (in the add-in card). Please take a look
into the spec of this card.

Regards,

Andreas


-----Ursprüngliche Nachricht-----
Von: Dinesh Kumar [mailto:eyesol@rediffmail.com] 
Gesendet: Freitag, 25. Oktober 2002 09:38
An: pci-sig@znyx.com
Betreff: DMA transfer over PCI


Hi all,
I have a PCI add-on card attached to Intel mother board.  The on 
board memory of target card is less (640 bytes ) so that it needs 
to transfer the data very frequently to host. Is it possible to 
initiate a  burst DMA transfer for less volume of data. Is there 
any minimum data volume requirement to trigger DMA across PCI. 
Please suggest the references.

Thanks in advance
Dinesh