It's been some time now since my last site update, mostly because of my lack of time...
Anyway, back to "work" with a new project : design a "Chat Mauve" video adapter clone at first, then maybe an enhanced version. The "Chat Mauve" adapter was designed to provide a RGB output on a SCART connector, for Apple //c computers. At Silicium, despite owning many Apple //c units, we've been able to find only one of those adapters so far, hence this idea of making a clone.
The adapter comes in a very small beige box. I opened it, expecting to find only a couple of passive components or simple logic chips in so few space, and I found myself quite surprised, as the box contains only a single custom chip (along with its voltage regulator) !
As expected, I didn't find anything useful on the web, so I searched for some information about the Apple //c video output and Apple II computers hardware. After some reading, it seems that making a RGB output out of the video signals provided isn't a trivial task, but doesn't seem too hard either.

Then I remembered a nice project I found on the web some time ago : the SUMP Logic Analyzer. It's an open-source FPGA-based logic analyser, with a client software in Java. It uses the Spartan-3 Starter Board as a primary target, which is fine, as I own one of those. So I decided to give it a try, as it should fit nicely for the project's purpose.

First step : put all the adapter's connector signals on a breadboard, and see which ones are used by the custom chip.



No big suprise here, almost all of them are used... Second step, set up the logic analyzer...



... and start analyzing, which is what I'm about to do now. I spent some time these last days to add a VHDL export to the SUMP Logic Analyzer Client, so I could use analyzer results as testbenchs for the upcoming design. On a side note, I'm using my Samsung NC10 "netbook" to run the logic analyzer client... Who said that netbooks are only suitable for basic tasks ? ;)