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The Icon Bar: General: For Sale: VIDC Enhancer boards
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For Sale: VIDC Enhancer boards |
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PaulV (19:25 24/6/2012)
sirbod (20:10 24/6/2012)
hairydalek (15:09 26/6/2012)
sirbod (20:26 26/6/2012)
PaulV (20:54 26/6/2012)
sirbod (22:54 26/6/2012)
PaulV (00:15 27/6/2012)
sirbod (07:21 27/6/2012)
PaulV (11:17 27/6/2012)
Phlamethrower (11:51 27/6/2012)
sirbod (13:12 27/6/2012)
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Paul Vernon |
Message #120684, posted by PaulV at 19:25, 24/6/2012 |
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Posts: 118
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As you're all probably aware, I've had a short run of VIDC Enhancer boards made and I'm now in a position to look at selling some of those boards. I've verified that the boards can be fitted to and work in the A300/A400, A400/1 and A3000 series' of Archimedes and have managed to create an installation and user manual for the boards covering all of these motherboards.
There's been quite a lot of insterest in the boards and there's a limited supply so I'm initially going to restrict sales to one per person although if there's enough interest, I may be persuaded to have another run of boards made.
The manual which covers pretty much everything you need to know about VIDC Enhancers and what they actually deliver for the Archimedes and you can download it from my site at the following address:
http://www.retro-kit.co.uk/user/custom/Acorn/3rdParty/RetroKit/VIDCEnhancer/manuals/VIDC-Enhancer-manual.zip
Before you place an order for one of them, I'd strongly recommend that you read the manual to see what's involved in fitting it and what the board can deliver.
Whilst I recommend the riser board config for the A300, A400 and A400/1 series of machines, you can fit the non-riser version of the board in a solder free configuration if you really don't fancy carrying out the work to install the riser board config. In general though, the Sync on Green fix that the riser board version delivers is a neat and flexible solution to that problem and gives you the best way of switching between different monitor types for the future on those machines.
I've created an order form where you can order (but not pay) for an Enhancer board as there's been interest from many different sources so managing that will be easier. I'll be taking orders on a first come, first served basis and contact you to confirm the order and arrange payment via PayPal or cheque if you prefer that.
So without further ado, here's the order form:
http://www.retro-kit.co.uk/Order-VIDC-Enhancer/
Paul |
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Jon Abbott |
Message #120686, posted by sirbod at 20:10, 24/6/2012, in reply to message #120684 |
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Posts: 402
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Pefect timing, my A440/1 turned up yesterday  |
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Paul Dunning |
Message #120705, posted by hairydalek at 15:09, 26/6/2012, in reply to message #120684 |
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It’s working well on my A300 series machine. |
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Jon Abbott |
Message #120708, posted by sirbod at 20:26, 26/6/2012, in reply to message #120684 |
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Posts: 402
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Working great on my A440/1, no more purple hue and MODE 31 (800x600) works great.
Just need to figure out how to get games to behave nicely! |
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Paul Vernon |
Message #120709, posted by PaulV at 20:54, 26/6/2012, in reply to message #120708 |
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Posts: 118
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That's great news from both of you. I've got the warm fuzzies knowing that there's a bit of hardware I built out there in the wild.
@Jon, with RISC OS 3 the game modes like 12 and 15 get re-mapped to VGA safe modes with odd screen sizes and refresh rates.
To that end, there is some letter boxing for some games due to the fact that the VGA re-mapped screen modes have 352 lines and the original screen modes have 256 lines. Because the 25.175MHz oscillator is still not available the letter boxing is worse on the older Arc's than those that do have the middle speed oscillator like the A5000.
Some later games are better though. Speedball 2 for instance detects the VGA monitor settings and adjusts to it accordingly so it looks like the NTSC Amiga screen mode which my Amiga version of Speedball 2 plays like anyway so it's very playable.
Zarch on the other hand, requires that you manually switch to MODE 15 before you launch the game. Rather interestingly, using a TFT screen with Zarch on and ARM3 processor removes the glitching that you see on a CRT monitor so it's still playable (although extremely fast).
Paul |
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Jon Abbott |
Message #120710, posted by sirbod at 22:54, 26/6/2012, in reply to message #120709 |
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Posts: 402
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Very high quality board, I'm very impressed.
re Games...Diggers uses 640x400 @ 50 or 100Hz - both result in an "out of sync" on the monitor, so I'm guessing the mode isn't being remapped.
At some point I'll start testing all the games on the A440/1, so will find out the other games with issues.
Is the module source code available, I'm curious to see what it does and if it can be modified to fix said games. |
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Paul Vernon |
Message #120711, posted by PaulV at 00:15, 27/6/2012, in reply to message #120710 |
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Thanks for your kind comments.
The VIDC Enhancer effectively multiplies the on board clock by a factor of 1.5 so I'm puzzled as to why you're seeing a vertical refresh rate of 50 or 100Hz. The 100Hz clock speed would be being put out if RISC OS was asking for a 70Hz remapped mode on the A400/1 series because it doesn't have a 25.175MHz signal, it asks for 70Hz but gets a refresh rate 4.7% slower because the clock is running at 24MHz so you end up with 66.7Hz or thereabouts. With the VIDC enhancer forced into its on state in that mode you'd end up with the 100Hz you're seeing...
The module source code is on the floppy that I packaged with the board. All it does is have a lookup table of modes and sets some to "Enhanced" when you change modes, it checks its lookup table and sets the AuxIO pin to high or low to activate or deactivate the Enhancer part of the board.
I've also been tinkering with the code and my alterations are in a second source file on the disc which changes the module name, default modes, * commands and finally the AuxIO pin that activates the board. I did this because I had a thought that I could double decker two VIDC Enhancer boards with one fitted with a 25.175MHz oscillator and feed the on board clock signal through both boards. Using two Aux IO pins to control the two boards.
Having two modules memory resident is a quick hack on my part to test out the feasibility of the idea and that part at least works. Ideally the functionality could be built into one module to control two VIDC Enhancer boards providing full speed refresh rates for the VGA modes so they'd be standards compliant and not need "forgiving" monitors to work correctly.
I've got a handful of 25.175MHz oscillators on order and I'm going to experiment a little bit with the code to see if I can achieve the functionality in the one module.
If it works it'll provide the re-mapped modes at the full 70Hz refresh rates and the letter boxing although still present will be less severe and match the output of the A5000 and later RISC OS 3 machines like the A30x0's.
My only concern is cross talk on the clock connecting cable so I'm not going to say it's entirely do-able until the 25.175MHz oscillators arrive...
EDIT: I should add, Appendix B in the manual I provided shows the modes RISC OS 3 generates. Any marked with note 3 are re-mapped when a VGA/SVGA monitor is in use.
Paul
[Edited by PaulV at 00:24, 27/6/2012] |
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Jon Abbott |
Message #120712, posted by sirbod at 07:21, 27/6/2012, in reply to message #120711 |
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Posts: 402
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Ah, that explains why Diggers misbehaves. It loads a module, which finds a free mode (by systematically testing if they're valid) and then creates its own 50/100Hz mode in the first free slot it finds.
I'll look at modifying the module code, so that is bases the remap on the requested screen's width/height instead of fixed modes. That may allow additional support for games with odd resolutions.
EDIT: Correction, Diggers uses 320x200 @ 50 or 100Hz
[Edited by sirbod at 08:31, 27/6/2012] |
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Paul Vernon |
Message #120713, posted by PaulV at 11:17, 27/6/2012, in reply to message #120712 |
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Posts: 118
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You can use the * command AutoVIDCset to set extra modes as being enhanced as at the moment Diggers will be relying on the 24MHz clock speed from the motherboard.
This does however mean you'd have to know what mode Diggers would be choosing in advance so if it's going along looking for an available non-defined mode to use. I'm not sure "Enhancing" the mode it creates will work though, you'd have to check both the H and V frequencies on your monitor and then see if it supports frequencies 1.5x those it reports. If it does, enabling the Enhancer should work.
Paul |
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Jeffrey Lee |
Message #120714, posted by Phlamethrower at 11:51, 27/6/2012, in reply to message #120713 |
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I'm not sure "Enhancing" the mode it creates will work though, you'd have to check both the H and V frequencies on your monitor and then see if it supports frequencies 1.5x those it reports. If it does, enabling the Enhancer should work. There are a couple of other options you could explore - the bottom two bits of the VIDC control register indicate what clock divider to use (1/3, 1/2, 2/3 or 1/1), so depending on which frequency Diggers is requesting you might find that you can change it to use a slightly different one that's a better match for your monitor. E.g. instead of 24MHz*2/3 (16MHz) you could use 36MHz*1/2 (18MHz).
Unfortunately, it looks like 18MHz and 36MHz are the only two additional frequencies that a 36MHz crystal will provide you, compared to the standard 24MHz one. |
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Jon Abbott |
Message #120715, posted by sirbod at 13:12, 27/6/2012, in reply to message #120714 |
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Posts: 402
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Yes, I'm looking through my paper copy of the original chipset manual at the minute, to see if its possible to manipulate the MODE after it's gone active to better match the monitor.
On the VIDC page, I found my notes from writing ModeExt and a long list of video mode register settings for some rather odd resolution modes - I can't for the life of me remember what they were used for! Great days LOL |
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The Icon Bar: General: For Sale: VIDC Enhancer boards | |
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