The Sinclair QL Forum

And with RASL/CASL of the QL's DRAM inactive, the multiplexer could be switched faster. I might overlook something, but I think even zero waitstates is doable despite the multiplexers. Fortunately the mux select and output enable lines are separate from RAS and CAS, as well as the DRAM WE. That bei...

And it is a bit more complicated, don't forget that ula in this bus has to check for the dsmc suddenly going high again by an expansion card and abort it's operation. So it can not function arbitrary fast or it will not give the card access. If it controlled all the ram and not the 128K it could ig...

Here's a little hint that might be useful: The QL memory map has an informal unassigned area of 16k right 'under' the bottom of the screen 0 RAM. Originally the on-board IO for the QL has been documented as residing in a 64k block of addresses starting at $10000, however, if one looks at what addres...

Unfortunately I don't have a GC, but I do remember there were several revisions of the INGOT for the GC, maybe that's the reason?

Maybe this has been addressed before but does your implementation uses the same pixel/memory layout as the 16 colour Aurora mode ? François No, this is based on regular mode 8 except the original flash bit is used as a brightness bit. It means that for each pixel, two bits out of four are in the ev...

Pr0f wrote: ↑Sun Dec 04, 2022 7:44 am ... A winding with 500mH inductance would give a reactance of 157 Ohms.

...And that would be very low for a primary reactance of that size transformer. The primary inductance will easily be in the tens of H region.

Excellent work Leon! The black version looks better to me. The reason why composite will look bad is that the patterning produces a 2.5MHz frequency component which is not well filtered in the PAL coding process (Sinclair used a simplified circuit for the PAL modulation chip which does not filter ch...

The extra resistors should be connected to the voltage divider before the series capacitor connected between it and the actual RGB pins of the PAL chip. The extra resistor should be connected to the common point of the 8.2k resistor from the RGB signals and 1k resistor to ground, as well as the afor...

AFAIK the ATF1508AS can be used in place of EPM7128S (as used here ). But at about the same price (ATF1508 is largest in range). ATF1508S can also be had in a TQFP100 package which is small and thin, so much so that with a multilayer PCB it may be possible to squeeze the whole board within the outl...

Checked, mine is the old CLA2310 in a ceramic case, so perhaps one of the first ones...