The Sinclair QL Forum

If you give me a schematic, I'll build it. :) If you can find out where the Trumpcard keeps it's ROM, and what addresses it uses for the WDC1772, I could do it easily. The actual RAM expansion bit is dead easy - 2x 512k x 8 SRAM, one GAL. And there would be plenty of space and free pins left in the...

The possibility of making more romdisqs does exist - if Tony Firshman is interested. That said, his design does use the very smallest flash chips that are near-impossible to solder by hand. I would have used a larger flash package and made the PCB 5mm wider just to make them much easier to assemble...

When the GF was designed, it was already clear that one would have to wait for some possible future ColdFire CPU that would put all that was taken out of the 68k architecture to make a Coldfire, back into it. In particular the debacle of the MCF5401 ColdFire MK1 which was actually a 68EC040 with a m...

Now, as I said, the actual CPLD programming was never written as a program, but it was designed. One overwhelming reason for this was that two competing companies that were the only ones at the time to produce sensible CPLDs that could be used, AMD and Lattice, ended up by AMD completely pulling out...

I'm confident a short run of low cost floppy interfaces with 512K of RAM will surface in the next few months from one source or another - there is sufficient demand. Why not make it two 512k SRAM chips and make it real snazzy - the extra cost is negligible (a WDC1772 costs more second hand than bot...

The trumpcard uses a PAL chip (at least the Trumpcard II which uses 256k x 4 RAM chips, so only 6 of them instead of the original 24!). However, you can do better today. The Trumpcard, for instance, uses a counter to generate a refresh address for the RAM, whereas even the 256k x 4 RAMs implement on...

HArdware-wise this is a very interesting interface. In theory it could just as well manage emulation of any keyboard with an 8x8 key matrix. It uses a MPU to interpret the key-presses of an XT/AT keyboard and writes it into an 8x8 dual-port memory, made out of TTL chips. The memory implements an 8x8...

OK this is going to be a long one (isn't it always :) ) but you did ask for it. What follows has a lot of references to the GF, a product that never saw the light of day, but that I spent a huge amount of time designing. What is more important, because it was to be a 'synthesis' of sorts of all prev...

QL systems are realistically limited to 512M (that shoould really be plently :P) since decoders must leave A29, 30, 31 as don't care. Otherwise Qliberator and anything compiled with it will not work. I can't imagine ever building a system with more than 16MB, since the most capacious SGC system has...

Here's where I'm at: 16MB 32-bit RAM (not all wired in) if used with an EC020 - up to 4GB with 68020 QL systems are realistically limited to 512M (that shoould really be plently :P) since decoders must leave A29, 30, 31 as don't care. Otherwise Qliberator and anything compiled with it will not work...