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Post by tokra on Feb 4, 2016 23:22:11 GMT
800x600 does not change the horizonal sync - it is still at 127 for register 0 = 128 char positions. I only let the display end at position 106 instead of 100 (register 35). You also need to change register 1 to 100 (to display 8*100=800 pixels) and adjust the horizontal sync-position (register 2). Here is the register-setting copied straight out of "VDC Mode Mania 1.1".
8020 data0,127,1,100,2,112,3,137,4,92,5,6,6,92,7,87,8,3,9,6,25,135,26,32,28,255,35,106,-1,-1:rem vdc 800x600 mono
It is a good idea to be careful with register 0 updates that go too high. One of my 1901s barely displays PAL-mode (at 15625 Hz) at value 127 for register 0, while the other can go up to 130.
Not really. In fact the reverse sync mode is only useful for old EGA-monitors. I was able to display a singal on a modern flatscreen without changing the sync (using the 8563 VDC-chip). VDC VGA Mania does exactly that. For that I have to lower register 0 to 63 (64 char positions) to get a horizontal frequency near the VGA-signal of 31469 Hz. I get to 16000000 / (64 * 8) = 31250 Hz which is close enough for most monitors. However the widest horizontal resolution I could get that way was 400 (50 chars) monochrome or 360 color (45 chars).
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Post by tokra on Feb 4, 2016 23:13:51 GMT
This effect works by changing register 34 (Display Enable start) from 125 to a lower value like 115. I can also force the effect on my 1901 by just turning the knob to shift the picture to the right. The usual value for Display Enable Start is 125, which means the display is enabled at position 125 of a raster line. On PAL you have 128 char-positions (register 0 = 127) and on NTSC 127 (register 0 = 126). As Hydrophilic calculated back on commodore128.org the VDC has a 16 Mhz Dot Clock. For NTSC you have 16000000 Hz / (127 * 8) = 15748 Hz which is the horizontal NTSC frequency and for PAL: 16000000 / (128 * 8) = 15625 Hz which is the horizontal PAL frequency. Of these 127 or 128 char-positions 80 are used on a regular text screen. Display is disabled at position 100 and re-enabled at the far right at position 125 (in anticipation of the next line). Apparantly the 1901 gets out of whack and displays strange colors if you re-enable the diplay during the flyback-phase. Nothing you can reproduce on other devices or sensibly use in a demo.
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Post by tokra on Feb 3, 2016 15:16:29 GMT
For VIC-1 (in VIC20) I have done some measurements on NTSC and PAL, you have to differentiate about what is displayed and theoretical values. On the 1084-monitor I can squeeze the picture and these are the maximum resolutions that displayed by the chip: PAL: 224x283 plus 284th line in rastercolor NTSC: 200x233 plus 234th line in rastercolor Theoretical values based on cycles: PAL: 71 x 4 = 284x312 NTSC: 65 x 4 = 260x261 For VIC-II there is info around the net, like dustlayer.com/vic-ii/2013/4/25/vic-ii-for-beginners-beyond-the-screen-rasters-cycle384 x 284 seems to be displayble on PAL-C64s when you can squeeze the picture. On VDC actually 720x700 is the largest resolution done yet. I have done 640x400 non-interlaced which would be 800 lines interlaced but that mode would need too much RAM. Problem with large resolutions horizontally and vertically are more the display-devices which are unable to display them because of their weird timing. As I showed with VDC VGA Mania you can squeeze a 31,5kHz-frequency out of the VDC but must reduce the horizontal resolution to do so.
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Post by tokra on Jan 19, 2016 10:13:57 GMT
I agree the post I quoted does not go too much into technical details, but basically I think it is right. Symbos limited to 128K would be "boring" and you could not really do much with it. As I understand Symbos needs a method to more or less instantly swap 16K blocks in memory. The REU can transfer 1 byte per cycle, so it would 32768 cycles to actually swap a memory block with the on-board-memory.
The VDC itself is another bottle-neck. All data has to go through the $d600/$d601 registers. GEOS 128 is a good example of what is possible with the C128 and 80 column-mode. I wouldn't completely rule out Symbos a possiblity on the C128 but a lot of ground work would need to be done regarding memory management with the REU and graphical display with the VDC. Whether it would be fast enough needs to be seen.
P.S.:Multicolor and interlace are very different concepts, but the VDC can basically do colourful graphics without interlace using the 8x2 mode for example. I'm not sure using interlace would be a good idea for an OS that you are supposed to actually work with.
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Post by tokra on Jan 14, 2016 13:54:28 GMT
There was post on the Yahoo Group for Symbos back in 2007 which I quote below: groups.yahoo.com/neo/groups/symbos8bit/conversations/messages/963Hi Julian, > I'm surprised no Commodore 128/128D owners having > requested a port, or have they? Yes, I had several requests for a C128 port. I met a guy on the VCFe in Munich 1,5 years ago who helped me to collect all necessary information about its hardware. I don't remember exactly, but maybe the MMU would make it possible to run SymbOS. Unfortunately there are several reasons, why a port doesn't make much sense: - the Z80 is clocked with 2MHz only, which is quite slow. - there is still no usable multicolour bitmap graphic mode. IIRC SymbOS would end up with 320x200x2 or 640x200x2. - there are no usable memory expansions, which provide that flexible banking SymbOS requires. They all were mostly only used as Ram discs and therefore do only provide a very limited memory mapping. That means, that SymbOS would be always limited to 128KB, which is boring. It's exactly the same reason, why a Spectrum +2/+3 port wouldn't make that much sense. Only B/W graphics (256x192x2 colours, as there is no bitmap mode) and not more than 128K, as the existing memory expansions do not allow that what SymbOS needs as a minimium. Somehow sad, but it also shows, which computers are really powerful ;-)) (just joking). CU, Prodatron
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Post by tokra on Nov 18, 2015 16:22:22 GMT
? Last I heard it was renewed for a third season to air summer 2016. Says so on amctv.com as well.
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Post by tokra on Aug 1, 2015 11:09:06 GMT
I´m using a GBS-8220 successfully on PAL with my Richard42-board. I´ve had a defective GBS-8220 before that did not work on either PAL or NTSC. I think "the GBS-8220 does not work on PAL" is a myth. This could easily be debunked since the VDC can be put into PAL or NTSC mode by software:
Set to NTSC: SYS DEC("CDCC"),32,4:SYS DEC("CDCC"),29,7:SYS DEC("CDCC"),126,0 Set to PAL: SYS DEC("CDCC"),38,4:SYS DEC("CDCC"),32,7:SYS DEC("CDCC"),127,0
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Post by tokra on May 28, 2015 8:08:23 GMT
The way I see this question is that you first have to calculate how many shares there are to give around. 4 "full" shares and 8 1/4 shares = 6 total shares. One "full" share = ($4,500,000 - $1,260,000) / 6 = $3,240,000 / 6 = $540,000 One quarter share = $540,000 / 4 = $135,000
So each grandchild will receive $135,000 and each child $540,000 8 x $135,000 + 4 x $540,000 = $3,240,000
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Post by tokra on Feb 26, 2015 22:12:09 GMT
Re-animating this thread... I sent in a bug to VICE back when I released my CP/M Tron-game: sourceforge.net/p/vice-emu/bugs/270/Z80 speed has been working a lot better since VICE 2.4, although now it is a little too fast, at least it's not half-speed anymore. Sadly, I really don't know C and have no real understanding of the VICE-codebase at all. I think between you and me we know the most about interlace-modes on the C128 and VIC20 - you with your VIC-IIe-interlace, me with all those VDC-modes and my two VIC-20 demos for NTSC-machines that use interlace. Especially VIC-20 NTSC-interlace is pretty straightforward, although there are still some timing issued with the NTSC-VIC-emulation in general that I would have to investigate further. For the VDC it would be good start if emulation allowed for larger screen areas first, and interlace later.
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Post by tokra on Jan 29, 2015 21:06:37 GMT
Interesting, what kind of hacks did you do to VICE and which does the VICE team include/not include? Do you file them on the sourceforge-project?
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