View Single Post
Old 14th May 2019, 5:38 pm   #36
john_newcombe
Pentode
 
Join Date: Apr 2019
Location: Skipton, North Yorkshire, UK.
Posts: 146
Default Re: Gemini 80-Bus System

Thanks for the info re: the IVC, I am using a 25ms strobe which was working fine and 4Mhz is provided from the backplane. I will have a probe around with a scope and see if I can come to any conclusions. I know that the Z80, CRT controller and RAM are all good so hopefully it will be something simple.

RPM_2.1.zip

The eprom came with the machine, I also have the versions 0.1, 2.0 and 2.2.

There was an article in 80 Bus News that described details of how to take v2.0 to v2.1 and then on to v2.3 (there was no 2.2, despite me having one!). When I get round to patching it I will post it here.
john_newcombe is offline   Reply With Quote