Author
| A possible alternative for the OCM?
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PingPong
msx master
Posts: 1026 |  Posted: June 24 2006, 11:24 |
Quote:
| @ping: I think they're somewhere on ESE's site. I doubt they're 100% up to date, but I remember seeing at least some V9938 code there.
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Can you give me the URL? |
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Sonic_aka_T
msx guru
Posts: 2269 | Posted: June 24 2006, 12:05 |
Quote:
| Quote:
| @ping: I think they're somewhere on ESE's site. I doubt they're 100% up to date, but I remember seeing at least some V9938 code there.
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Can you give me the URL?
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y00 lazy git!  |
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Sonic_aka_T
msx guru
Posts: 2269 | Posted: June 24 2006, 12:14 |
oh, and here is the VDP code...  |
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PingPong
msx master
Posts: 1026 | Posted: June 24 2006, 12:32 |
Quote:
| oh, and here is the VDP code...
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very thx! |
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legacy
msx professional
Posts: 516 | Posted: June 24 2006, 12:54 |
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Leo
msx freak
Posts: 238 | Posted: June 24 2006, 23:09 |
I am trying to port this code from ohanaka on the digilient board with a spartan 3S.
I have a problem because there is one SRAM on this board which access have to be shared
between cpu and VDP. I have some solutions but it always end up with strange video signal.
Though i can see the msx basic1 boots on the RTL I have . I am currently preparing my wedding
for the very next weeks so I will see this problem later on august.
I have Xess and digilent board with spartan 3S1000 , the vdp+z80+rom+psg+ppi fit in 40% of the core.
I recommend the Z80 core from fpga arcade, the one from opencores is buged.
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flyguille
msx master
Posts: 1225 | Posted: June 25 2006, 04:59 |
which? the one z80 that can runs up to 250mhz?
is severals, which you means?
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Leo
msx freak
Posts: 238 | Posted: June 25 2006, 10:35 |
At first I had a version with VDP+Z80 and minimal rom of 2K all inside the fpga.
Actually a Z80 alone can run fast but with external sram this slows down.
For instance : there is a 10ns access sram on digilent board + I budget 10ns for pad/pcb delay => 20ns period = 50MHz Freq.
Moreover If this access is shared between VDP/CPU , the speed is around 50/2 = 25MHz.
In fact I use the same 21MHz clock for VDP and Z80.
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PingPong
msx master
Posts: 1026 | Posted: June 29 2006, 19:57 |
Quote:
| Moreover If this access is shared between VDP/CPU , the speed is around 50/2 = 25MHz.
In fact I use the same 21MHz clock for VDP and Z80.
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Do you mean that you have somewhat that emulates z80+vdp ready ? At stage of test?
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Prodatron
msx master
Posts: 1110 | Posted: June 29 2006, 22:30 |
Btw, you can download the complete source code of the CPC TREX core here:
http://www.symbos.de/download/cpctrex-quartussnapshot10.zip
The very interesting thing here could be the completely new Z80 implementation: It needs only half of the LEs of the OpenCore T80, is very fast and seems to be completely bug free. The only disadvantage is, that it's not commented. |
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Leo
msx freak
Posts: 238 | Posted: June 30 2006, 22:14 |
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PingPong
msx master
Posts: 1026 | Posted: June 30 2006, 22:22 |
Thx, I already know this. I was thinking you had your own implementation...
Do you think it is possible to have a "turbo" VDP implementation?
(More quicker commands, more than 8 sprite per horiz. scan line? for example?) |
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AuroraMSX
msx master
Posts: 1264 | Posted: June 30 2006, 22:26 |
Quote:
| Do you think it is possible to have a "turbo" VDP implementation?
(More quicker commands, more than 8 sprite per horiz. scan line? for example?)
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This one could give you a start |
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wolf_
msx legend
Posts: 4781 | Posted: June 30 2006, 22:28 |
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Sonic_aka_T
msx guru
Posts: 2269 | Posted: June 30 2006, 23:27 |
Quote:
| Do you think it is possible to have a "turbo" VDP implementation?
(More quicker commands, more than 8 sprite per horiz. scan line? for example?)
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That should be fairly easy, a matter of a few values I suppose. This would of course decrease backwards compatibility unless it could be made 'switchable' which would be a bit more difficult I guess. |
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