Search found 513 matches

by iss
Fri Dec 08, 2017 10:59 am
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

Clipboard01.jpg Clipboard02.jpg Clipboard03.jpg Well, this are samples with the changed schematic (AND instead NAND), now the reference SYNC is BEHIND the derived SYNC's with exactly 1 full period, so no big difference and in common it doesn't matter which variant will be used. For me the important...
by iss
Thu Dec 07, 2017 8:47 pm
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

@NigthBird: No, I don't think this simplification will work. After the XOR we must have NOT to invert the logic and enable the clock only when the clocks are the same . BUT , (looking again at the traces) if we change the NAND to AND (7400 -> 7408) then maybe the 1/2 cycles delay will be eliminated...
by iss
Thu Dec 07, 2017 11:27 am
Forum: Games
Topic: Blake's 7 feedback and review thread
Replies: 97
Views: 4113

Re: Blake's 7 feedback and review thread

Attached is 'Floppy.cpp' from the SVN with fixed CRC. I added missing 'compute_crc' calls where they are needed.
Floppy.cpp.zip
(8.83 KiB) Downloaded 4 times
by iss
Wed Dec 06, 2017 1:29 pm
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

At end one interesting case ! Clipboard04.jpg Clipboard05.jpg Here, after power-on the reference ULA started with 60Hz but the child ULA's with 50Hz. This actually confirms that the synchronization logic works :). To not happen such case, the reference ULA should be fed with proper data to initializ...
by iss
Wed Dec 06, 2017 1:10 pm
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

Clipboard02.jpg
Clipboard03.jpg
On the traces CLK, CLK1,CLK2,CLK3 are 12Mhz clocks and VSYNCH/HSYNC are visible.
You can see how the reference SYNC is 1/2 of the 12MHz period before the child's SYNCH's.
I think It's worth to sacrifice one ULA as reference.
(continue below...)
by iss
Wed Dec 06, 2017 12:40 pm
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

Hello all! Below are updated schematic and test results. I think we have working synchronization :) sch.jpg 20171206_014751.jpg In short how it works: I used one ULA (U2) as reference, its SYNC signal is compared with the SYNC form a "child" ULA (U5,U6,U7), so if both SYNC's are the same then the cl...
by iss
Thu Nov 30, 2017 9:09 pm
Forum: Hardware hacks and extensions
Topic: And now, box for the controller.
Replies: 7
Views: 738

Re: And now, box for the controller.

The Good, the Bad and the Ugly :) 20171130_213534.jpg 20171130_213704.jpg 20171130_213745.jpg I started with the right one using ABS material, but the result was extremely fragile - the supports broke before printing was finished. The left and the middle boxes are from PLA material and they are real...
by iss
Thu Nov 30, 2017 12:26 pm
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

Is the printer port bi-directional? I thought it could only send data. I'm sure you know this well ;), it's bi-directional, every bit can be set independently as IN or OUT, think about the joysticks... About the RAM overlay - if it's requirement then maybe microdisc for every machine is best choice...
by iss
Thu Nov 30, 2017 10:37 am
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

Yep, I think the parallel port is the best option for communication between machines - easy to drive and no additional hardware. Maybe it will be better to use it as kind of (a)synchronous serial interface with two lines STB (for output) and ACK (for input), emulating something standard as protocol ...
by iss
Thu Nov 30, 2017 8:42 am
Forum: Hardware hacks and extensions
Topic: Microdisc controller + Amplibus, do you want another batch? CLOSED LIST.
Replies: 86
Views: 24597

Re: Microdisc controller + Amplibus, do you want another batch?

I'm candidate! If there is no other with more urgent needs I'll take it "as is" - controller+amplibus. My reason to want it is that I just printed 2 boxes but have only one controller. They are so beautiful (I will post pictures in related thread). :mrgreen: If you put my name on laurentd75's place ...
by iss
Thu Nov 30, 2017 12:50 am
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

4.jpg 5.jpeg ... and here is the setup. The idea was to power-on the thing, so all ULA's are well "saturated" and then using the button to enable the clock signal, hoping that all ULA's will run synchronized. It didn't work, but at least it was easy to build. :lol: This weekend I'll try to make som...
by iss
Thu Nov 30, 2017 12:29 am
Forum: Technical questions
Topic: Merging video output?
Replies: 32
Views: 1566

Re: Merging video output?

1.jpg
2.jpg
3.jpg
3 ULA's in parallel - more details below...
by iss
Mon Nov 27, 2017 5:17 pm
Forum: Technical questions
Topic: Right angle IDC connector
Replies: 4
Views: 189

Re: Right angle IDC connector

http://uk.farnell.com/3m/d3431-5302-ar/connector-header-34pos-2row-2/dp/2672493 http://uk.farnell.com/amp-te-connectivity/2-5499141-8/header-r-a-34way/dp/1298809 Previously I used to buy from their local distributor and they are fine. See at bottom of pages for alternatives (if not available on stoc...
by iss
Thu Nov 23, 2017 11:59 pm
Forum: Emulators
Topic: Yet Another (EDIT: now also for Linux)
Replies: 46
Views: 10781

Re: Yet Another

Cool! ... and it works! :) Nice RGB and composite emulation. All my DSK images are running fine, but I found that original Blake's 7 (v1.1 - English) fails to boot, there is error after each sector was read: CRC error; terminating Maybe the problem is in the image (Chema?). One wish from me: I want ...