| 6502.org http://forum.6502.org/ |
|
| CRTC core http://forum.6502.org/viewtopic.php?f=10&t=2151 |
Page 1 of 2 |
| Author: | Dajgoro [ Fri Apr 13, 2012 2:49 am ] |
| Post subject: | CRTC core |
Hi! In another topic, i was discussing the idea of a 3d module. But as for now it lacks a important component, and that is a sort of CRTC (video display generator) that would generate 8 bit color(R 2-bit,G 2-bit,B 2-bit,Luma 2-bit, i suppose this scheme would work) graphics, with the max resolution of 192x256(for now). I don't really know how pal video is generated, so i don't really know how to make this from scratch. Could someone strip down some other project that implements color video generation, so it might be adjusted to fit the description. It would be great if this would fit in a XC9536 cpld, because they are kinda inexpensive. Also it should be similar to the MC6847, continuously loading pixels from video ram, with the fs signal output. This could be used to develop future projects, also it could be used in other projects(any project where there is a mcu that does some sort of graphic, and renders it). I also made a c++ program in visual studio that emulates the device described above, it works fine on win xp, but on win7, it displays in super slow motion... Is there a good and simple way to display simple graphics in C(i tied many solutions that Google gave me, but none worked). |
|
| Author: | BigEd [ Fri Apr 13, 2012 4:32 am ] |
| Post subject: | Re: CRTC core |
Hi Dajgoro The PACE project has some video controllers in VHDL, including the 6847: https://svn.pacedev.net/repos/pace/sw/s ... ent/video/ Cheers Ed |
|
| Author: | ElEctric_EyE [ Fri Apr 13, 2012 9:14 am ] |
| Post subject: | Re: CRTC core |
Also, Peter Wendrich has written a version of the VIC-II, 656x for C-64 in VHDL in the Syntiac Pages. Hunt inside the .zip file. |
|
| Author: | fachat [ Fri Apr 13, 2012 2:40 pm ] |
| Post subject: | Re: CRTC core |
ElEctric_EyE wrote: Also, Peter Wendrich has written a version of the VIC-II, 656x for C-64 in VHDL in the Syntiac Pages. Hunt inside the .zip file. But watch for the license... - as far as I read it, it is not what OSF would call open source (IANAL) André |
|
| Author: | ElEctric_EyE [ Sat Apr 14, 2012 12:20 am ] |
| Post subject: | Re: CRTC core |
Very true! I did not read his license... Bad habit of mine... At least he has posted his work, so others can learn from the code without explicity copying and using it. That attitude I can appreciate! |
|
| Author: | Dajgoro [ Sat Apr 14, 2012 11:58 pm ] |
| Post subject: | Re: CRTC core |
Thanks for the links! mstram (Mike) maild me this fpga soc system that he found, with an integrated vga controller, link: http://www.fpgacpu.org/xsoc/ |
|
| Author: | Arlet [ Sun Apr 15, 2012 6:22 am ] |
| Post subject: | Re: CRTC core |
If somebody makes the hardware, and sends me a board, I'll volunteer to write some Verilog for a video generator. |
|
| Author: | Dajgoro [ Sun Apr 15, 2012 2:55 pm ] |
| Post subject: | Re: CRTC core |
I could build a board, but i currently only have xc9536 cpld, can this cpld be used, or would you need something more powerful(the xc9573?). I aim on cheap components, and some fpga can be really hard to find and expensive(i also like the plcc package, since i can solder the socket on perfboard), i also usually shop on ebay... |
|
| Author: | Arlet [ Sun Apr 15, 2012 3:19 pm ] |
| Post subject: | Re: CRTC core |
Here's a display controller using an XC95108: http://elm-chan.org/works/crtc/report.html It's probably hopeless to try to fit in a smaller device. And his design even includes an external IC for PAL/NTSC modulation. Of course, you could use the 65org16 Dev board. It has everything required for video generation, and plenty of room left over in the FPGA to add some 3D functionality. |
|
| Author: | Dajgoro [ Sun Apr 15, 2012 3:40 pm ] |
| Post subject: | Re: CRTC core |
This is great, but i can't find any XC95108 in plcc on ebay, any other cheap store where i could get one, without getting robbed on shipping prices? |
|
| Author: | Dajgoro [ Sun Apr 15, 2012 4:05 pm ] |
| Post subject: | Re: CRTC core |
Could this fit in the XC9573 if the resolution is shrunken down to 192*256? |
|
| Author: | Arlet [ Sun Apr 15, 2012 4:36 pm ] |
| Post subject: | Re: CRTC core |
Dajgoro wrote: Could this fit in the XC9573 if the resolution is shrunken down to 192*256? Hard to say, but as that would only save 2 or so macrocells, it's not very likely. |
|
| Author: | Dajgoro [ Sun Apr 15, 2012 6:23 pm ] |
| Post subject: | Re: CRTC core |
Any suggestions where to find the 95108 in plcc? |
|
| Author: | BigEd [ Sun Apr 15, 2012 6:36 pm ] |
| Post subject: | Re: CRTC core |
I tried to investigate the implementation. The project is described in ABEL HDL (pdf), which needs an older version of the Xilinx tools: perhaps version 10 is the latest which will support it. I had some success using 8.2 command-line tools (with cribs from here) to convert to user-unfriendly vhdl and then synthesising in version 11. It still failed to fit a XC95108-7-PC84 with default tactics or even with adjusted tactics: Code: Mapping a total of 108 equations into 6 function blocks....................................ERROR:Cpld:892 - Cannot place signal VSI. Consider reducing the collapsing input Attempting to reduce the input or product term limits seem to lead to an impasse with:limit or the product term limit to prevent the fitter from creating high input and/or high product term functions. Code: ERROR:Cpld:837 - Insufficient number of macrocells. The design needs at least 109 but only 108 left after allocating other resources. So this design does seem to be right on the limit, if not a little over. Probably re-writing the ABEL in a modern HDL and studying the implementation would be the thing to do, if it is worth pursuing - or using the supplied JEDEC files if it is good enough as is, which means targeting the exact device. Cheers Ed |
|
| Author: | Arlet [ Sun Apr 15, 2012 6:42 pm ] |
| Post subject: | Re: CRTC core |
BigEd wrote: So this design does seem to be right on the limit, if not a little over. Nice work. Fitting this in a smaller device is even more impossible than I had guessed. |
|
| Page 1 of 2 | All times are UTC |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|