Search found 1156 matches

by tofro
Mon Nov 20, 2017 5:29 pm
Forum: QL Emulation
Topic: Q-emuLator and macOS High Sierra
Replies: 5
Views: 304

Re: Q-emuLator and macOS High Sierra

Try typing anything with either caps lock on or the shift key held down - the letters appear correctly, but space, return, delete, the arrow keys - none of these respond. A general bug or just my setup? Keyboard membrane of your emulated QL is probably broken - They tend to do that with age. Order ...
by tofro
Sat Nov 18, 2017 5:40 pm
Forum: General QL Chat
Topic: Sinclair QL printer (Seikosha) cable
Replies: 8
Views: 396

Re: Sinclair QL printer (Seikosha) cable

Simon, on the DB-25 end, 1 is "Shield" (which is normally GND) and 7 is "signal ground" (which is normally GND as well). For non-exotic applications like QL-to-printer, that is the same. So, feed 7 of the 9-pin to both 1 and 7 on the DB-25. On second thought, shielding (the mesh ...
by tofro
Fri Nov 17, 2017 12:45 pm
Forum: Hardware
Topic: Q68 Notice 3 - Update
Replies: 43
Views: 1957

Re: Q68 Notice 3 - Update

Speed reduction: Note that, even if the contention created by video circuitry eats a lot of memory bandwidth, the 256 and 64k colour modes are way easier (and faster) to handle than the original QL modes: Setting a pixel in mode 4 or 8 means ⋅ pick the word containing the pixel from video ...
by tofro
Tue Nov 14, 2017 3:17 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 658

Re: Engineering mules....

I remember that article from QL User, but can't remember whether it actually worked. It apparently doesn't attempt to reset the 8049. Jan. Jan, as far as I remember, this shouldn't be necessary - The 8049 resets itself already when seeing <CTRL><ALT>7 after sleeping for a while. Before that, it iss...
by tofro
Tue Nov 14, 2017 12:09 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 658

Re: Engineering mules....

The simplest you can do is have QMON loaded in your QL - That redirects the level 7 interrupt into the debugger.

Tobias
by tofro
Mon Nov 13, 2017 7:27 am
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 658

Re: Engineering mules....

My guess is the debugging device was software only (Some specific ROMs). I have, however, never heard of any of such versions that would have survived. So I'd guess another time and assume these ROMs were made on the go when looking for a specific problem and later discarded.

Tobias
by tofro
Sun Nov 12, 2017 10:33 am
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 95
Views: 5965

Re: Microdrive Unit Design

Technical docs and hardware shows there are 2 heads, so your calculations need to reflect that 2 heads are in use. Erm, no. Probably not. There is no mechanism that ever uses the two tracks on the tape in a parallel way . The tracks are being used for alternate bits , most probably to compensate fo...
by tofro
Thu Nov 09, 2017 12:17 pm
Forum: Hardware
Topic: PSU alternative?
Replies: 55
Views: 8135

Re: PSU alternative?

Setting the ground reference of the +/- 12 V lines to the +9V line looks weird, at first, but you need to look into the PSU in order to understand it. Sinclair has simply saved on one strand of wire, the 14VAC ground. Most probably, the complete transformer is one continuous winding, the input to th...
by tofro
Thu Nov 09, 2017 11:07 am
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 95
Views: 5965

Re: Microdrive Unit Design

vanpeebles wrote:This has been a very enjoyable and interesting thread to read :)

...so far. Please keep it going ;)
by tofro
Wed Nov 08, 2017 1:19 pm
Forum: Software & Programming
Topic: QubATA 3.10 I/O area address
Replies: 9
Views: 365

Re: QubATA 3.10 I/O area address

I just had a short check on it: The driver appears to do some interesting things: In windev_asm (INIT), it seems to copy itself from ROM into allocated RAM and patch the detected hardware addresses directly into the code. Not the most RAM-efficient method, but would make relocating the driver to som...

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