Search found 613 matches

by iss
Sat Apr 28, 2018 1:16 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Apple nibbles are '5+3' for the old 13 sector format, and '6+2' for the 16 sectors format which we are using. First are read 256 octets, they hold 256 x 6-bit bytes and next 86 octets give additional 2 bits. I succeeded to fix loading with help of temp 256-bytes buffer without any speed impact! :) H...
by iss
Thu Apr 26, 2018 9:31 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

So no a bug... a feature ? ;)
Sure! The most important thing is always to think positively :).
by iss
Thu Apr 26, 2018 9:27 pm
Forum: Technical questions
Topic: 8DOS: overlay RAM control?
Replies: 6
Views: 586

Re: 8DOS: overlay RAM control?

I guess the engineers at Pravetz really internalised the idea of soft switches! The engineers from Pravets only stole Oric but they forgot to 'borrow' Microdisc too. :) The FDC is entirely 'one man show' - the author of the hardware and DOS-3.3 adaptation is Borislav Zachariev - student at that tim...
by iss
Thu Apr 26, 2018 8:43 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Thanks for the rich info about NIB and WOZ image formats, ThomH! The minimum I wish to add to Oricutron is support of any sector interleave. Else I think it's not worth to add half- and quarter-track positioning ability and all that stuff which in the Apple's world is used for different protection s...
by iss
Thu Apr 26, 2018 8:09 pm
Forum: Technical questions
Topic: 8DOS: overlay RAM control?
Replies: 6
Views: 586

Re: 8DOS: overlay RAM control?

Everything you wrote is correct. 8D FDC is exactly the same as Apple][ and it uses the 16-sector WOZ state machine P6 ROM. All 16 FDC registers are the same and are mapped at $310..$31F. There are only 2 differences from Apple: - no slots ; - boot ROM is shorter version - only 224 bytes instead of A...
by iss
Tue Apr 24, 2018 11:13 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Well done - the "special build" works! I'll make a clip tomorrow. But I noticed one bad effect - in an undetermined moment graphics mode is switched back to text :?, pictures continue to be loaded but the mode remains text. In ~90% of cases when this happens is the Oric-1 picture just loaded, but I ...
by iss
Sat Apr 21, 2018 1:07 pm
Forum: Technical questions
Topic: oric atmos boot stuck at AA pattern
Replies: 14
Views: 932

Re: oric atmos boot stuck at AA pattern

Nice work, seb! About the R0* in my old post - it depends on amplification of the particular chosen transistor - it should be in range 200 Ohms ... 2kOhms, or maybe even more. It's not danger to experiment with any R value, the best is to use 10k trimmer and adjust the picture. I think you can get b...
by iss
Fri Apr 20, 2018 11:11 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Well, I finished the new controller and I'm very happy to say it works perfect! On the right is old broken one FDC, on the left - the new beast (still with trimmers for fine adjusting of the MAP signal), 20180421_000450.jpg And here is my version of the slideshow "as is" running on real hardware: :s...
by iss
Fri Apr 20, 2018 10:48 pm
Forum: Tape and floppy disk converters
Topic: FloppyBuilder evolution
Replies: 89
Views: 38709

Re: FloppyBuilder evolution

I'm advancing slowly in FloppyBuilder for 8D-FDC hardware. Here you can see optimized version of my test demo from previous post running on real 8D FDC. It's faster than in Oricutron :). [media]https://youtu.be/Vs5_dNjJal0[/media] I'll make some code cleanup and will post sources and all technical d...
by iss
Tue Apr 17, 2018 10:33 pm
Forum: Technical questions
Topic: Microdisc connectors
Replies: 10
Views: 1067

Re: Microdisc connectors

Generally powering trough expansion slot is not wrong and it 'highly likely' ;) will work always. Although for me it's not good practice for very simple reason - the purpose of ribbon cables (and connectors) are to be signal cables i.e. for low currents (for instance about 100mA) where Oric wants >6...
by iss
Tue Apr 17, 2018 10:15 pm
Forum: Technical questions
Topic: oric atmos boot stuck at AA pattern
Replies: 14
Views: 932

Re: oric atmos boot stuck at AA pattern

+1 for diagnostic ROM else the usual suspects are RAM chips - btw, very interesting rare chips Inmos Ims2600.
Do you have any modifications on back of the PCB? And one easy thing: check if the NMI button works i.e. its contacts are not permanently connected.
by iss
Tue Apr 17, 2018 9:49 pm
Forum: Technical questions
Topic: Microdisc connectors
Replies: 10
Views: 1067

Re: Microdisc connectors

And about the PSU. Here is one broken original Microdisc PSU - the plastic insulation is so old that it's not 'plastic' anymore. It waits silently its turn to be repaired one day... :) 1.jpg 2.jpg But more interesting here is the schematic (sorry for the ugly drawing): 3.jpg Important thing is that ...
by iss
Tue Apr 17, 2018 9:29 pm
Forum: Technical questions
Topic: Microdisc connectors
Replies: 10
Views: 1067

Re: Microdisc connectors

As to powering the Oric, normally this is done directly from the Microdisc through the ribbon cable to the Oric... I think normally you can't power Oric with the ribbon cable. This is original Microdisc controller - pin 33 on the ribbon connector is not connected to +5V track. Yes, it looks like it...
by iss
Wed Apr 11, 2018 8:19 pm
Forum: Technical questions
Topic: Microdisc connectors
Replies: 10
Views: 1067

Re: Microdisc connectors

Reference to Microdisc connectors here and here (China 10 pcs cheep but long waiting) and an eBay search . Maybe you can find them somewhere closer to your place. About the power supply - I suppose you have a PC PSU - if so DON'T USE the 12V to power Oric together with Microdisc and floppies - there...
by iss
Sun Apr 08, 2018 3:32 pm
Forum: Operating systems
Topic: FastBoot/FastLoad on Pravetz 8D/Disk II
Replies: 35
Views: 2872

Re: FastBoot/FastLoad on Pravetz 8D/Disk II

Great sources! :)
One VIA specific thing: the value for timers must be '-2' for precise timings, i.e. #4FBA-2=#4FB8.
And this 1.0205 Mhz - I think it's apple][ clock, for Oric in my opinion it need to be exactly 1.0 MHz.