The Sinclair QL Forum

Here's a brief outline on some projects I am working on. The main reason for 'slowly' is because I am not a programmer. I think none of my machines (and they included so many new peripherals) would have been possible, if I had not written basic software support for all of them myself . I usually di...

I am thoroughly surprised a 700MHz ARM based SOC sould not read fast enough from GPIO. Someone is not programming it very well... usually bare GPIO (ports) can run at 25+ MHz speed, which is actually enough since once a byte/word is read, the rest of processing works at full speed. Surprisingly, no...

Dave wrote:

lezanderson wrote:Real time Clock & Calendar for Time Date: DS12887/DS1310 etc

There's so many RTC choices it's sickening....

For a chance of software support, it could make sense to use the Q68's DS1374 which includes a reset generator.

I recall the high precision timer in the Q68 is 40MHz. I don't know if that just happened to be the clock of the Q68, or if there was a specific reason you chose that, but 25ns is a nice time interval because it is so easily countable to get "real" times. I was also considering a clock ti...

It is interesting that the Q68 has 2 SD slots. I saw two card slots mandatory, in case someone wanted to use the Q68 as a stand-alone QL-style computer. In this case, one needs the possibility to copy or backup mass storage from one media to another. Doing this via RAM disk would be uncomfortable f...

On the Q68 extension bus, can the /DS data strobe be used as a reliable clock, for example as a timer or to clock data into/out of an external device? I know this seems obvious, but there's some subtleties to it I don't understand. Sorry Dave, it is my shortcoming not to have documented the timings...

I think it might be easier from a hardware perspective to have a 32,768 Hz timer, and if that is too fast simply /2 for 16384 Hz. That frequency would be of restricted use, e.g. it is too slow to generate network timings. If there are enough registers available, I'd recommend the CPU clock (Pin 25 ...

BTW - given recent experience re-working the QNET driver around Q68's hardware-timer, I can say that any 8302 replacement should have a high precision timer included - it would make any further QNET driver development soooo much easier... A high-precision timer is also helpful for other tasks, wher...

The SUBJECT TO CONDITIONS is that this device would not support microdrives because of strict timing, and also would likely not support QLNET. The QLNET timings depend almost completely on the 68K CPU and its memory. The added delay by the 8302 register accesses should be neglegible. As far as I ca...

It should be noted that (to my knowledge) the only hardware dependent things used directly and not through an OS driver are the RTC seconds counter in the 8302 and the mode control register in the 8301. Not quite ;) During compatibility tests of the Q68, Detlef found that few (two?) games access th...