Originally Posted by Jacques
And what will happen in case +2MB trapdoor could be set by its jumpers to add +0.5 MB CHIP (1 MB in total) by itself, will the rest of SLOW/FAST add to the ACA500 RAM?
That might work. I always had the internal 1.8MBytes memory expansions in the back of my head when I designed the ACA500. These expansions were popular in Germany, and since they were a lot more cost effective than any external memory expansion, I think they were popular outside Germany, too.
Keep in mind that only a few of these 1.8M expansions can turn part of the expansion into Chipram. While it is *possible* to do that all with just a Gayle-adapter (and no CPU adapter), I don't know if the knowledge how to accomplish that was already out there in the late 80s/early 90s when these expansions were popular. Those expansions that actually worked with 1M chip and 1.5M ranger-mem mostly used a CPU-adapter, but that won't work properly with the ACA500.
So.. if you have one of those rare internal expansions that give you 1M chipram and 1.5M ranger-mem with just a Gary-adapter but no CPU-adapter, then you can expect it to work with the ACA500. If you are unsure if your expansion will work properly, I'm happy to take a close look at the Gary-adapter - please open a new thread in another part of this forum for that, so we can discuss technical details outside this news-thread.