Re: PCcard (2)

jbevren_at_starbase.globalpc.net
Date: 2001-04-10 01:42:26

On Mon, 9 Apr 2001, David M. Lloyd wrote:

> On Mon, 9 Apr 2001 jbevren@starbase.globalpc.net wrote:
> 
> > If you're wanting to do DMA from an ISA card, you can have the DRQ
> > lines cause an interrupt on the c64, which would react by tristating
> > the 6522(s) and then asserting DACK.  After this, you can use "Pseudo
> > DMA", which consists of convincing the card that its on a (very slow)
> > DMA channel by manually toggling the lines to clock data in.  Mind
> > you, ISA's dma doesnt provide the destination address from the
> > expansion card.  It's actually the DMAC's responsibility to do this,
> > so we dont need to change the address lines.  We simply provide ISA
> > bus signals. *wink*
> 
> Or you can do it in hardware with a 6844 or 68B44 from Motorola, you
> should still be able to get them somewhere.  Then you can have _real_ DMA

This product is discontinued.  I wont use it ;)

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