Is this, then, inaccurate?
If the 4000 supports dma to the mediator from fast & chip memory...
A4000 with Buster 9 and 11 does support DMA to fast memory on the motherboard and the chip memory, as well as between Zorro III cards. DMA from Zorro III to CPU board memory must be supported by the CPU card (e.g. all phase5 cards do).
Regarding the Mediat*r4000: it has six Zorro III slots (plus one for the bridging card), but the Buster has only five bus request lines... strange. But to decide if it does DMA from Mediator to Amiga, check the following:
- does it work with Buster 7? If so, it is non-DMA, as Buster 7 doesn't support Zorro III DMA *at all*. There's no way of checking the Buster revision in software, so you would have to activate DMA by a software switch.
- does the software ask about Buster 9 or 11? DMA is buggy on Buster 9, and you need to take some workarounds for this, so if the software doesn't care about these differences, DMA is unlikely.
- check the bridging card between Zorro III and PCI: check pins 60 (/BRn) and 64 (/BGn) on the Zorro connector. These two lines are mandatory for Zorro III DMA (as well as E7M on pin 92); if they are not connected, Zorro III DMA is *not* possible at all. If they are connected and DMA is active, then short low pulses on /BRn (140ns, synchronized to raising edge of E7M) must be there, as well as longer phases with /BGn being low (which is DMA active).
Michael