Search found 171 matches

by janbredenbeek
Thu Nov 23, 2017 9:58 pm
Forum: Software & Programming
Topic: Q68 Powered Arcade Game
Replies: 22
Views: 581

Re: Q68 Powered Arcade Game

That is exactly what is hidden behind the "scheduler list" concept mentioned above - The scheduler is driven by basically the same 50/60Hz timer that also drives the vertical blank interrupt. Same concept, other name. A scheduler list is a routine address you hand over to the OS to be cal...
by janbredenbeek
Sat Nov 18, 2017 12:04 pm
Forum: Hardware
Topic: Q68 Notice 3 - Update
Replies: 44
Views: 2101

Re: Q68 Notice 3 - Update

Hi Peter, A few more general points, when it comes to Q68 purchase decisions: 3. Ethernet: This was only tested on a hardware level. Although I had some experience with QL native TCP/IP and ethernet 15 years ago, I can not promise to release driver software for the Q68. It is possible that I do some...
by janbredenbeek
Wed Nov 15, 2017 9:49 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 669

Re: Engineering mules....

Hi Nasta, Thanks for the extensive explanation, though I have one small correction: IPL1 generates interrupt level 2, not 1. The original 68000 had three lines IPL0, 1 and 2, corresponding to the binary equivalent of the interrupt levels. On the 68008 IPL0 and 2 are tied together giving Level 5 when...
by janbredenbeek
Wed Nov 15, 2017 2:29 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 669

Re: Engineering mules....

Full recovery may not be possible. True, you don't know what already has been corrupted by the time you press CTRL-ALT-7. It's use is mainly to inspect memory and registers for debugging purposes rather than to give you a chance to save your work after a crash (which you should do regularly anyway)...
by janbredenbeek
Tue Nov 14, 2017 4:11 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 669

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, 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 issues t...
by janbredenbeek
Tue Nov 14, 2017 2:29 pm
Forum: Hardware
Topic: Engineering mules....
Replies: 16
Views: 669

Re: Engineering mules....

Hi, just wandering what is the line, ZX8302 uses to raise `mdv gap interrupt' to MC6800. IPL1? It's used to read the microdrives - when a gap on the tape passes the head the interrupt is triggered so the 68008 can read in the sector or sector header. It's also used for the 50Hz interrupt - QDOS onl...
by janbredenbeek
Wed Nov 08, 2017 3:06 pm
Forum: General QL Chat
Topic: Error message on #1
Replies: 8
Views: 418

Re: Error message on #1

Hi Christian I would doubt an MDV hardware fault giving rise to the #0/#1 message behaviour. As for #0 being free or busy - if the cursor has already returned and flashing - as is often the case once the save routine has successfully written and during the automatic verify phase - then #0 will be '...
by janbredenbeek
Mon Oct 30, 2017 8:56 am
Forum: Software & Programming
Topic: FTYP of sub-directories on SDC...
Replies: 11
Views: 575

Re: FTYP of sub-directories on SDC...

As I remember from a TT interview in QL Today, the original idea behind duplicating the header information in both the directory and file itself was to make microdrives more robust against a damaged directory file. Incidentally, the MDV driver stores the complete file information in the file header ...
by janbredenbeek
Sun Oct 29, 2017 2:19 pm
Forum: Software & Programming
Topic: A guide to programming the Sinclair QL
Replies: 25
Views: 1202

Re: A guide to programming the Sinclair QL

I've written several programs in C when I was already an experienced QL coder (it was not before the early 90s when C68 appeared which was the first decent C compiler for the QL). I even wrote a library in C to implement pop-up windows and menus as I didn't want to rely on the PE when distributing p...
by janbredenbeek
Sat Oct 28, 2017 9:25 am
Forum: Hardware
Topic: QL MODE 8 Flash Bit
Replies: 12
Views: 654

Re: QL MODE 8 Flash Bit

I've done it in a Videotex/Viewdata/Prestel terminal program. [...] That explains how well you knew about the Flash bit details! Thanks for explaining it on ql-users! Pity that your program will hardly be of use on the Q68... Now when I think of it... Teletext is still being used here in NL, it's e...

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