SX52 Protoboard NTSC project
cbmeeks
Posts: 634
galaxy.signaldev.com/~cbmeeks/gpu/
**I hope this isn't in the wrong place but since it is centered around the SX52, I thought it would be OK.**
These are some pics of my SX52-based GPU. I am building a home-brew computer and am currently working on the video section.
I have to admit, I have "stolen" most of the video design from Andre' Lamothe's XGS. But, he is aware.
Anyway, I have written plenty of B/W and even some color rasters in software but when it comes to color, you NEED hardware to get any kind of performance. I have been tweaking/experimenting with Andre's design.
In a nutshell, what he does is take some buffers and a couple of multiplexers to create a hardware delay for the color burst signal. Works pretty well! The SX52 has almost no work to get color.
I won't say I am going to improve his design, but I am going to try and get a few things that the XGS doesn't do (to my knowledge). For example, the XGS will not let you get a complete range of colors on one scanline. You can get MOST of the NTSC color wheel but not all. To get the last half, you have to change your color burst and use a negative reference. I really don't like doing this. I'm not knocking him, just I want something easier.
For example, the Commodore 64 had 16 colors and you could have all 16 on the same scanline without any tricks. I want the same.
I do have about 14 colors now with 8 levels of luma (over 100 colors). But, some are really unstable and some actually destroy the sync! Argh!!
Anyway, I just thought I would open the doors for discussion if anyone is interested. If so, I can post better pics of my board, drawings, etc.
Thanks!
cbmeeks
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
**I hope this isn't in the wrong place but since it is centered around the SX52, I thought it would be OK.**
These are some pics of my SX52-based GPU. I am building a home-brew computer and am currently working on the video section.
I have to admit, I have "stolen" most of the video design from Andre' Lamothe's XGS. But, he is aware.
Anyway, I have written plenty of B/W and even some color rasters in software but when it comes to color, you NEED hardware to get any kind of performance. I have been tweaking/experimenting with Andre's design.
In a nutshell, what he does is take some buffers and a couple of multiplexers to create a hardware delay for the color burst signal. Works pretty well! The SX52 has almost no work to get color.
I won't say I am going to improve his design, but I am going to try and get a few things that the XGS doesn't do (to my knowledge). For example, the XGS will not let you get a complete range of colors on one scanline. You can get MOST of the NTSC color wheel but not all. To get the last half, you have to change your color burst and use a negative reference. I really don't like doing this. I'm not knocking him, just I want something easier.
For example, the Commodore 64 had 16 colors and you could have all 16 on the same scanline without any tricks. I want the same.
I do have about 14 colors now with 8 levels of luma (over 100 colors). But, some are really unstable and some actually destroy the sync! Argh!!
Anyway, I just thought I would open the doors for discussion if anyone is interested. If so, I can post better pics of my board, drawings, etc.
Thanks!
cbmeeks
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
Comments
I've been checking out your progress on the XGS forums.
could you post a better pic of the gpu or a schematic.
nice work!· I hope to get more involved with the XGS this winter.
DAN
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DTQ
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks