Search found 342 matches

by Nasta
Tue Jan 14, 2020 11:08 pm
Forum: Hardware
Topic: QL-VGA
Replies: 33
Views: 1187

Re: QL-VGA

As far as I know, there isn't a version of the 8301 ULA that actually implements this. It was obviously planned but may never have been implemented. Actually I tried "POKE hex('18063'),64" on my German issue 6 or something QL and the display gets weird and the poll frequency changes to 60...
by Nasta
Sun Jan 12, 2020 4:35 pm
Forum: Hardware
Topic: QL-VGA
Replies: 33
Views: 1187

Re: QL-VGA

Dave wrote:Since the NTSC flag in the 8301 allows 60Hz output, would that simplify things? Or is the 60Hz tied strictly to different resolutions?


As far as I know, there isn't a version of the 8301 ULA that actually implements this. It was obviously planned but may never have been implemented.
by Nasta
Wed Jan 08, 2020 12:24 am
Forum: Hardware
Topic: Issue 8 discussions...
Replies: 143
Views: 18312

Re: Issue 8 discussions...

Well, running late on this side cause I had to re-install the computer, which involves putting a new OS on it and then putting the old one in a virtual machine on the first one. On the plus side, this ended up with my current 27" 2k monitor being replaced by a 40" 4k TV which I'm using as ...
by Nasta
Wed Dec 11, 2019 9:44 pm
Forum: Hardware
Topic: Issue 8 discussions...
Replies: 143
Views: 18312

Re: Issue 8 discussions...

I discovered a small error in the schematic, the /BGACK line on the CPU must be connected to +5V instead of /BG (corrected on the schematic).
The rest should be fine and accept the GAL code I prepared.
by Nasta
Sat Dec 07, 2019 11:22 pm
Forum: Hardware
Topic: Issue 8 discussions...
Replies: 143
Views: 18312

Re: Issue 8 discussions...

Well, I have a few minutes to write here, so here goes: I have all but dropped out of the project for a while because job stuff interfered. Unlike most other jobs, my (now ex-)job comes 'into season' during summer and especially in August and September, but as other co-operants are involved which us...
by Nasta
Fri Oct 11, 2019 11:37 pm
Forum: Hardware
Topic: DIY QubIDE Parts list
Replies: 15
Views: 1710

Re: DIY QubIDE Parts list

top.jpg bottom.jpg Note red arrows. There are a couple of different problems, when you can see the outline of the PCB pad around the solder, it's likely a bad/cold solder joint/ There are also a few pins on the SIL resistor pack where the surrounding ground fill has been exposed, and it's possible ...
by Nasta
Thu Oct 10, 2019 10:06 am
Forum: Hardware
Topic: Microdrive spinning ad infinitum...
Replies: 30
Views: 2210

Re: Microdrive spinning ad infinitum...

The inductors on the switching regulator produce a rather large stray field which is probably being induced directly into the head and electronics. Even on the original QL the left microdrive has a metal shield between it and the motherboard stuff and in that setup there is FAR less electromagnetic ...
by Nasta
Tue Oct 08, 2019 10:19 pm
Forum: Hardware
Topic: Microdrive spinning ad infinitum...
Replies: 30
Views: 2210

Re: Microdrive spinning ad infinitum...

Check that the 8302 ULA is well and alive. This sounds like either an interrupt is left 'hanging' or the MDV select signal or some other logic is - in either case, it's the 8302 that generates those control signals. Reversing the 5V polarity is REALLY dangerous and can easily damage any chip in the ...
by Nasta
Tue Oct 08, 2019 10:13 pm
Forum: Hardware
Topic: DIY QubIDE Parts list
Replies: 15
Views: 1710

Re: DIY QubIDE Parts list

Someone else may know if this should work? (I'm not familiar with this board, or it's circuit diagram) If you remove all the plug-in IC's ( it looks like the two SMD IC's have something to do with the IDE socket), and plug it in. Does the QL work normally, or do you still get the bars? If you do th...
by Nasta
Tue Oct 01, 2019 8:20 am
Forum: Hardware
Topic: DIY Fpu Unit for STFM
Replies: 28
Views: 4634

Re: DIY Fpu Unit for STFM

Hi, Cannot help thinking more about $Fxxx and $Axxx. The emulation can be achieved through exception trap vectors. As on plain MC68000/8 $Fxxx and $Axxx machine code instructions simply do not exist. So the attempt excecuting them leads to an exception that can be caught by a handler. The respectiv...