UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Gemini 80-Bus System

john_newcombe · 8th Jul 2019, 9:02 am

Hi Neal, wow!, thank you for your assistance.

The anomaly around the CRTC is down to my notes being a tad messy. The /OE /WE stated for the CRTC were in fact the signals for the Workspace RAM. The IORQ is signalling the CRTC as expected.

I will check the MUX lines as you suggest and then move on to check the DOT clock and IC25.

I have the RP/M monitor installed in the main CPU so should be able to install and run some code to do some I/O on port 0xb3.

I will let you know how I get on...

8th Jul 2019, 9:02 am	#137
john_newcombe Hexode Join Date: Apr 2019 Location: Skipton, North Yorkshire, UK. Posts: 252	Re: Gemini 80-Bus System Hi Neal, wow!, thank you for your assistance. The anomaly around the CRTC is down to my notes being a tad messy. The /OE /WE stated for the CRTC were in fact the signals for the Workspace RAM. The IORQ is signalling the CRTC as expected. I will check the MUX lines as you suggest and then move on to check the DOT clock and IC25. I have the RP/M monitor installed in the main CPU so should be able to install and run some code to do some I/O on port 0xb3. I will let you know how I get on...