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Building an internal grayscale card for the SE/30

nickpunt

Well-known member
Congrats @Bolle that's huge! 😁

As for the greyscale, can't wait to see & hopefully be able to pick up a copy of the final product!
 

reukiodo

Active member
Any plans to integrate it with your replacement se/30 board? (and maybe integrate asante ethernet while you're there?) ;)
 

Mac-Man

Member
I’m new to this forum and I’m probably asking a dumb question, but would 256 greyscale graphics significantly slow down the speed of the Mac?
 

Byrd

Well-known member
It does, but having an accelerator negates the slow down which I'd imagine most would also be using in a souped up SE/30 with greyscale. My experience with a SE/30 PDS video card (640 x 480 x 256 colours) is colour games suitable for higher end '030 Macs are relatively slow
 

Mac-Man

Member
Thanks for the explanation Byrd! In that case it would probably not be very useful without an accelerator, but cool it’s possible nonetheless.
 

APPLCOLC

Member
It does, but having an accelerator negates the slow down which I'd imagine most would also be using in a souped up SE/30 with greyscale. My experience with a SE/30 PDS video card (640 x 480 x 256 colours) is colour games suitable for higher end '030 Macs are relatively slow
About this, would it be the main processor that the greyscale card uses, or would it be the FPU? I don’t exactly know all too much about hardware, but I have a feeling using numbers besides binary (like the Mac’s black and white) would have to use some sort of integer. I wouldn’t know, however.
 

GeekDot

Well-known member
0, 1 and every unfractioned number until infinity is an integer;-)

All used in this case is the CPU and the bus. Very simple said: the CPU writes bytes over thr bus into video RAM. A digital-analog coverter creates signals for the CRT. Voila: A picture.

It's simple bitmap graphics. Thr faster the CPU can shift bytes, the faster the graphics.
No fancy blitters or acceleration involved here.
 

GeekDot

Well-known member
I’m new to this forum and I’m probably asking a dumb question, but would 256 greyscale graphics significantly slow down the speed of the Mac?

Just as an appetizer and to soothe your concerns... it's not really slowing things down.
Here's the Speedometer 4.02 QuickDraw benchmark comparison to a Color Classic.

20220511_165815.jpg

...aaaand that's at the same resolution as the Color Classic (i.e. 512×384, not 512x342)
[Yes, that's a really battered SE/30... it's my test Guinea pig - just in case it goes up in flames 🔥 :devilish:]
 

Mac-Man

Member
Thanks for sending the comparison GeekDot! I also found out the Color Classic actually has the same processor speed as the SE/30, so now my concerns are basically gone. I do have another question though. As far as I can tell from reading this forum, and also by seeing your picture of the comparison, that this graphics card will only support 8-bit grayscale mode. Is this correct? If it's not capable of switching to other graphics modes (especially 1-bit), will this not break/crash some games/applications that needs this?
 

olePigeon

Well-known member
@Mac-Man I believe the grayscale mod is intended to be used with a video card. So the ability to display other graphics modes would be completely dependent on the video card that is installed. I've never owned one, but I would guess that B&W is still there. I have run into the occasional video card that skips 16 colors, though, which is annoying.
 

GeekDot

Well-known member
Thanks for sending the comparison GeekDot! I also found out the Color Classic actually has the same processor speed as the SE/30, so now my concerns are basically gone. I do have another question though. As far as I can tell from reading this forum, and also by seeing your picture of the comparison, that this graphics card will only support 8-bit grayscale mode. Is this correct? If it's not capable of switching to other graphics modes (especially 1-bit), will this not break/crash some games/applications that needs this?
This is correct... at the moment.
The original Formac ProNitron card on which this design is based used a software controllable "switch" to change the video clock(-devider) so that it could display 1- and 8-bit.
@Bolle had a hard time fiddling with this and ended up doing "8bit only" for now. But he can fill you in much better than I can... I'm just the software guy (and happy to flick that switch any time 😉).

So yes - Currently, if a game/application insists on b/w it will get a "𝖁𝖊𝖗𝖇𝖔𝖙𝖊𝖓!" from the card and send back home :cry:
 

Mac-Man

Member
Thanks for the explanation again @GeekDot, that clears up a lot of uncertainties I had. I hope that you and @Bolle are able to figure out how this "switch" works, that would make the card a whole lot more useful. In any case, I'm really impressed what you guys have done so far. Ever since I was a child I dreamt of grayscale mode on (back then) my dad's SE/30. I now got that Mac working again thanks to all the helpful info on this website.
 
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