A2091 and Zorro-II DMA memory

[Heiroglyph]

Wow, that's an eye opener to me.  I thought you couldn't do DMA with ZorroII cards to high memory.

I knew the lines were there, but assumed the cards weren't made to support it.

[Heiroglyph]

Ah, ok, that's what I thought.  Thanks for clearing that up.

[Heiroglyph]

The lines aren't there, it's impossible for a zorro 2 card to use more than 24 bits of address. While zorro 3 cards use the same connector, the extra address and data bits are multiplexed.
 
The easiest way of making sure there is memory available for the card to DMA is to populate the A2091 with ram.

Dang, I hoped nobody would call me on that one :roflmao:

I have no idea what I was thinking.  I've been looking at bus specs so much the last few days my brain must have just scrambled the two.