The Sinclair QL Forum

I consider the chat a strictly private conversation. It is like persons meeting in a room or a phone conference in real life. I'd like to be asked for permission, even if the chat is recorded only privately. And I clearly disagree that a log with my chat conversation becomes public. If this is chang...

I'm looking for a working replacement keyboard, which fits into the QL case, called the Schön keyboard. Only German version.

See here: http://www.rwapadventures.com/ql_wiki/i ... ards#toc_1

With ISA at least the buffering was relatively well defined, while on the QL it's either non-existent or a rather haphazard combination of all sorts of things. I'll get back to this a bit later on regarding SGC/Aurora Absolutely. Whenever I talked about the extended connector pinout, it was under t...

ISA (16-bit) has a few more ground lines interspersed, and the empty area is actually a bit smaller due to vertical connectors being used on a motherboard with 4 layers and decent buffering, not like the QL. Still it runs at about max 2x the speed legally and when the 16-bit extension is used - so ...

-> Dave: Isn't it more relevant what future QL gear would plug into it? -> Nasta: The HF return path length is not what matters for the inductance, but the area encircled by it (and the signal line). If both PBCs have decent ground planes (and I don't see why there would be a large hole in those pla...

The intent is to create a grounded area with no loops larger than 30cm possible. I can not follow you here. Using only C29 and C30 as additional GND pins would result in about 7 cm max. distance from any pin (including GND) to the next GND pin. Indeed: in 30 years, a very much needed accessory card...

There is a problem created by the ground and power pins being at opposite ends of the connector, which has caused ground/signal integrity problems for Nasta in the past. Placing a ground point close to the VIN pins seems a solid decision. That could be C29 and C30, 4 pins seems a bit much. Address ...

I might add that I had actually considered designing a video converter chip using these signals. I was only hindered by lack of time and higher importance of other QL projects. Compared to a full video controller, using these signals does not require data and address lines, so there is much less 5V ...

The cable should not be too bad, because every second line is ground, which allows defined impedance. However, SDHC cards differ in driver strength, so I really have no idea which length is possible.

[...] although it would be interesting to see whether an Aurora may impact on this at all. I'm also curious, because the Aurora offers much better signal quality than the QL mainboard. There is also the question of THOR / Q40 / Q60 users - and whether any of the options will work on those machines,...