PCG graphics on MZ 800

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fitus
Posts: 48
Joined: Tue Jun 12, 2018 8:52 pm

PCG graphics on MZ 800

Post by fitus » Mon Mar 09, 2020 9:28 pm

Hello,
is it possible to use PCG graphics on MZ 800 Basic (1Z016)?

Sharpals
Posts: 23
Joined: Sat Jul 14, 2018 5:39 am

Re: PCG graphics on MZ 800

Post by Sharpals » Tue Apr 14, 2020 1:44 pm

i´ll think no :-(

Please look at ste sm800 page at page 7.

You can use it in MZ700 Mode and in Basic, if you write by hand ( poke and in,out ) values into that area at $C000 - $CFFF ( CGram )

In MZ800mode the CG area is used as DRAM ...

But you have an Patterncomand in MZ800 Basic and you can define your own patern and draw them on screen.

PATTERN
( PAT. )
800 Allows the user to define his own graphics pattern. It is used in the form PATTERN [PC,sm]n,text data
The colour specification consists of palette code and superimpose mode, although this can be omitted, in which case the current colour specification will be used. The command must be followed by the number of rows of 8 dots, and the actual format of each row is controlled by the text data which must correspond to the binary representation of the dot patterns.

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HajdaM
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Joined: Sun Apr 05, 2020 11:29 am

Re: PCG graphics on MZ 800

Post by HajdaM » Wed Apr 15, 2020 9:06 pm

Basic 1Z016 has no support for MZ-700 PCG mode as far as I know. It supports only 320x200 and 640x200 modes with or without extra DRAM.

Technically it could be possible to switch to MZ-700 mode in assembler call and do some drawings and maybe switch back ;-)

Instead of CGRAM Basic has an area in memory on address $2000 which is used to store what characters are on each position of the screen - there could be characters on screen even if they are not drawn and vice versa.

To draw a character, I believe drawing routine switches to rom memory to access characters map, but it's possible to use POKE to change which address of memory is used. This allows to introduce alternative characters mapping if that is what are you after. Some Basic programs used $EFE0 memory area to store alternative mapping.

I created some primitive editor of character mappings in BASIC back in the days, if you want to take a look in emulator. But it's only in Czech language ;-) "N" followed by empty text will load one of two included mappings and "V" will switch BASIC to use it - almost like a font...
https://hajdam.zdechov.net/download/?sh ... finice.zip
Image

fitus
Posts: 48
Joined: Tue Jun 12, 2018 8:52 pm

Re: PCG graphics on MZ 800

Post by fitus » Sun Apr 19, 2020 9:36 am

I understand Czech quite well ;) . Thanks for information. I am trying to get to life some ´´software projects´´ from my childhod...

Sharpals
Posts: 23
Joined: Sat Jul 14, 2018 5:39 am

Re: PCG graphics on MZ 800

Post by Sharpals » Fri Jul 10, 2020 1:50 pm

Technically it could be possible to switch to MZ-700 mode in assembler call and do some drawings and maybe switch back
If you do that, your screen will be destryed :-( ( Ok not your hardware :-) )

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