The Sinclair QL Forum

Hi Martyn,

martyn_hill wrote: Wed Jul 02, 2025 9:03 am If @Peter is reading this, I do have a question regarding how QIMSI Gold compares to the Q68/QZero in terms of memory access contention when running tight software loops - in particular, whether there is the same uncontended memory area (SRAM) available on the QIMSI-G, or, if indeed there is no requirement to use the same mechanism I employed in ND-Q68 of relocating the physical NW routine/Supervisor Stack into SRAM to ensure consistent timing?

Yes it has the same SRAM area $19000...$1BFFF, and the same mechanism should be applied.
Additionally, it has SRAM from 0 to $7FFF, which the Q68 has not.

martyn_hill wrote: Wed Jul 02, 2025 9:03 am This will have a bearing on how swiftly I can adapt ND-Q68 to the QIMSI-G...

It already works fine.

Hi Dilwyn,

dilwyn wrote: Wed Jul 02, 2025 9:39 am I wasn't too sure from reading the QIMSI Gold manual if the 47ohm resistor and clamp diode are already on the board

Yes they are.

dilwyn wrote: Wed Jul 02, 2025 9:39 am (so needing only the 330 ohm resistor on the jack socket contact?).

Yes, only the termination resistor.

dilwyn wrote: Wed Jul 02, 2025 9:39 am What held me back from adding the network was the worry over a third cable tugging on the fairly fragile connection on the ROM slot (accidentally moving the video cable is sometimes enough to upset the QIMSI).

My advice would be: Get one of the fantastic cases from Marcel_X. It provides good mechanical stability: QIMSI (Gold) without case is no fully satisfying solution mechanically - but using the expansion port would have increased costs and made it difficult to use (Super)GoldCard, TrumpCard, QubIDE etc. as companion. Which can be useful in order to copy files from IDE drives, floppy or microdrive.

I did consider an expansion port "carrier board", where QIMSI Gold could be mounted more firmly. But that would further increase the variety of devices that I need to design and support. Another distraction from the more important QL60 project. Maybe an idea someone else could implement.

Hi Peter!

Peter wrote: Wed Jul 02, 2025 9:20 pm Hi Martyn,
It already works fine.

Oh, great! That is a relief - one less item on my To-do list!