Re: How to test if your memory card is DMA compatible?

[David Wilson <mcs6502@gmail.com>]

On Jun 4, 1:50 am, "AMart79...@gmail.com" <AMart79...@gmail.com>
wrote:
> How do you test if your memory card is DMA compatible?  Is there a
> specific program to use to test this??

If the memory card has more than 4 banks of 256KB (max 1MB) or 4 banks
of 1024KB (max 4MB) then it is not DMA compatible as the IIgs memory
slot only provides 2 bits of bank selection.

To have more than 4 banks a card must decode A16..A23 from the data
bus during phase 1. The only problem with this is that while the 65816
outputs this, the DMA circuitry does not. A program could not test
this without an appropriate card to generate DMA data flow.