[BBC-Micro] Reversing the Tube ULA (destructively)

John Kortink kortink at inter.nl.net
Tue Oct 26 11:23:32 BST 2010


On Tue, 26 Oct 2010 08:03:58 +0100, "David Harper"
<dl.harper at btopenworld.com> wrote:

>[...]
>
>The 80186 does DMA and uses the Tube to do it in the Master512. It does 
>this, however, simply by using the normal Tube data transfer facilities, but 
>the DRQ line from the Tube chip is connected to DRQ0 on the processor, 
>rather than NMI as it is for some other processors.

I've not seen any copro that uses DRQ-out as NMI-in.
After all, there's an NMI-out.

Have I missed one ?


John Kortink

-- 

Email    : kortink at inter.nl.net
Homepage : http://www.inter.nl.net/users/J.Kortink

GoMMC, the ultimate BBC B/Master/Electron storage system :
http://web.inter.nl.net/users/J.Kortink/home/hardware/gommc

ReCo6502, the Acorn 6502 Second Processor on steroids :
http://web.inter.nl.net/users/J.Kortink/home/hardware/reco6502




More information about the bbc-micro mailing list