Color GAL5, color board for MZ80KC/1200

psmart
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Re: Color GAL5, color board for MZ80KC/1200

Post by psmart » Fri May 01, 2020 3:34 pm

Hi,

When I made the first version of the board I didn't have as much info as I do now, the designs are more an evolution than ground up design so all the information your providing and what Im digging up should hopefully result in a better v2 design.

In all honesty, I didn't fully consider compatibility with the MZ-700, I dug up what information I could find and noticed that Nibbles Lab used his own attribute definition and the information I had to hand was the MZ-700 manual hence basing this boards attribute definition on the 700. After going through a set of old books recently I found my old MZ-80A manual and on page 167 (attached) it showed the A's definition for the attribute RAM. So I need to take this all onboard and produce a design which is fully compatible with the 700 (ie. disable bit 3 in 700 mode) and with the 80A specification for the attribute. How I will map this in with the CGROM selection will need some thought, perhaps in 80A mode the CGROM selection is by U9 only.

wrt CP/M: It makes sense to have a standard ASCII CGROM, I do the mapping in the CBIOS at the moment, the case exists for both where an 80A has 80col mode but no CGROM adapter or a board like this design where you can maintain both the original CGROM (for non CP/M programs) and an ASCII CGROM for better CP/M compatibility.

It is food for thought, thank-you, the next board I also want to have the DIN output sockets, any idea why there were 2 cutouts?
IMG_1226.jpg

psmart
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Re: Color GAL5, color board for MZ80KC/1200

Post by psmart » Fri May 01, 2020 4:08 pm

Just had a quick check, the manual on the original.sharpmz.org is different to my original manual. Mine is dated September 1981 and has a lot more pages, it also has the serial number 080311-250981.

hlide
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Re: Color GAL5, color board for MZ80KC/1200

Post by hlide » Fri May 01, 2020 6:48 pm

MZ-80 A: I was unaware of that information. But the color format from the color display connector is just 8 plain bits with non specific meaning. It is up to you to decide what to do with those D0-D7. The page you posted probably concerns a color board they did which has that interesting color lever (do they mean level?). In fact, to what does that level apply? to foreground? to background? to both in a character basis? I would expect more having 16 colors (R,G,B and L) for both foreground and background.

Honestly, I wonder what it would be more useful, more color sets or more character sets.

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Re: Color GAL5, color board for MZ80KC/1200

Post by hlide » Fri May 01, 2020 6:56 pm

Just as an example for my 1024-character set board in my MZ-700 (using D3 to expand a 512-character set into double). I added that 256-character set as semigraphics 4-level 2x2 blocs:
mz-700 CGROM-G.png
mz-700 CGROM-G.png (110.21 KiB) Viewed 2275 times
I always found the original 16 "2x2 square dot" blocks ugly.

The character format is:

Code: Select all

D0-D1: "Color" of upper left "pixel"  
D2-D3: "Color" of upper right "pixel"
D4-D5: "Color" of lower left "pixel"
D6-D7: "Color" of lower right "pixel"
 
Color: 00 is full background, 01 is almost background, 10 is half foreground, half background and 11 is full foreground.

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Re: Color GAL5, color board for MZ80KC/1200

Post by mz-80a » Fri May 01, 2020 7:00 pm

psmart wrote:
Fri May 01, 2020 4:08 pm
Just had a quick check, the manual on the original.sharpmz.org is different to my original manual. Mine is dated September 1981 and has a lot more pages, it also has the serial number 080311-250981.
Yeah, that doesn't match up at all with my MZ-80A manual whatsoever. Never seen that. And never seen colour on an MZ-80A
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Re: Color GAL5, color board for MZ80KC/1200

Post by hlide » Fri May 01, 2020 7:12 pm

The advantage of using D7 and D3 in attribute byte is that you can pick up to 1024 characters on the same display (supposedly you fit your set in SRAM and you can alter it, you can do 320x200 graphics). That's another reason I'm not sure having European and Japanese characters in the same 1024-character set (with a lot of duplicated characters) is a good choice.

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Re: Color GAL5, color board for MZ80KC/1200

Post by psmart » Sat May 02, 2020 2:13 pm

I had a more closer look at my manual, the MZ80A was purchased circa mid 1982 and it has a similar number of pages to the pdf on original.sharpmz.org, the latter is either lacking pages or skips the blanks in its pdf numbering. I've attached the differences that I could see without page by page comparison.

My apologies hlide, I kept typing hilde and not hlide as your username!!! I lived in Germany for quite some time so I must have been reading what I expected rather what was printed!!!

It is very interesting the way you have managed a CGROM to give pixel graphics, this was one of the things that the Sharp MZ80's and 700 lacked, it would have been so easy for Sharp to have added it but I guess memory wasn't cheap back then. Taking your information on board, I can use some of the extract latch U9 outputs to give options, either original MZ80A as per the attached manual, MZ700 where bit 3 is always 0 or your design where you map 4 character sets to give appearance of pixel graphics.

The MZ80A Im guessing it is intensity of the whole character, foreground + background, probably not so relevant but nice to keep things as close to original as possible. Nibbles Lab probably knew this because his design uses D5:D0 as the colours and he ignores D7:D6.

Many thanks.
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psmart
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Re: Color GAL5, color board for MZ80KC/1200

Post by psmart » Sat May 02, 2020 2:16 pm

IMG_1228.jpg

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Re: Color GAL5, color board for MZ80KC/1200

Post by psmart » Sat May 02, 2020 2:17 pm

IMG_1229.jpg

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Re: Color GAL5, color board for MZ80KC/1200

Post by mz-80a » Mon May 04, 2020 6:23 pm

psmart wrote:
Sat May 02, 2020 2:13 pm
I had a more closer look at my manual, the MZ80A was purchased circa mid 1982 and it has a similar number of pages to the pdf on original.sharpmz.org, the latter is either lacking pages or skips the blanks in its pdf numbering. I've attached the differences that I could see without page by page comparison.

I have literally never seen those pages. And I have owned a number of different MZ-80A manuals before passing them on to other people. This is my own one:
IMG-5564.jpg
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