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MrDave

Coco background. Color

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2 hours ago, MrDave said:

Does anyone know if the screen color can be changed in the color basic rom ? I can easily reprogram the rom..

Ask what you can do for your coco .. not what your coco can do for you

 

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Yes, it can be changed...   

I'm not sure exactly where in the ROM it is, but I can ask some people I know...

 

All the Smart People I know that know the CoCo hang out on a Discord Server....

 

MarkO

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Ahh i seen you on cocotalk.. i'm dave of dave & sharron. Lol i suppose if i really wanna play with the roms i could swap in a static ram to figure everything out by trial.. but someone must have done it already...

Thanks

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On 12/24/2019 at 7:35 AM, MrDave said:

Does anyone know if the screen color can be changed in the color basic rom ? I can easily reprogram the rom..

I was under the impression that the text (and background) colour was fixed by the 6847 video chip. I have never seen any software that changes the standard BASIC/OS screen colour.

 

There is a software way to switch the screen to an orange colour; it is used in the cartridge game Poltergeist. Alas, I have long since forgotten the details. 

 

It is also possible to force inverted video (light green text on a darker green background), but that requires a hardware modification.

 

If you look at some of the few other applications of the 6847 video chip (including a prototype computer adapter for the Atari 2600!), they all have the same 32x16 green screen with black text. 

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When i piggy back soldered in my 6309 on top of the 6809 cpu a couple of pins had a bad connection and funny enough the background was orange with no text.. but im sure the basic rom must till the vdg which starting mode to use...

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Funny from basic i can poke at ff22 to change modes to real lower case.. orange background  orange or green outside border and inverse the screen too ! It looks like orange on dark red really cool.. but as soon as basic tried to print it put it back to green lol. If i cant find it in rom i may hardware attack the vid chip !

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Posted (edited)

Ok so I have this figured out now

On alot of coco2's even in xroar ( coco2b mode)

Poke &H0167,&H39

Poke &HFF22,&H78

The first command locks out basic from resetting the vdg the second is a poke into the vdg the 7 can be a 7,6,5,4,3,2,1,0 and the second digit an 8 for orange or 0 for green

The top bits are for wideScreen..inverse,,lowercase. Try it out !

20200104_184910.jpg

Edited by MrDave

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Posted (edited)

My sweet coco2 6309e / 6809e ..dual cpu ..dual eprom !

 

20200104_222639.jpg

Edited by MrDave

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On 1/4/2020 at 6:42 PM, MrDave said:

 

20200104_184910.jpg

 

Was there any commercial (or even amateur) software that used this mode? 

 

I am unsure if I like it more or less than the standard green screen. Neither is choice is great. 

 

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Not sure about commercial software.. but text based applications like edtasm etc are alot nicer like this

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On 12/28/2019 at 5:53 PM, MrDave said:

Ahh i seen you on cocotalk.. i'm dave of dave & sharron. Lol i suppose if i really wanna play with the roms i could swap in a static ram to figure everything out by trial.. but someone must have done it already...

Thanks

 

Yep, that's me...   One of the CoCoTALKers that's been there since the First Show...  ;)

 

The Tandy CoCo Discord Server is https://discord.gg/4J5nHXm

 

MarkO

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On 1/4/2020 at 5:42 PM, MrDave said:

Ok so I have this figured out now

On alot of coco2's even in xroar ( coco2b mode)

Poke &H0167,&H39

Poke &HFF22,&H78

The first command locks out basic from resetting the vdg the second is a poke into the vdg the 7 can be a 7,6,5,4,3,2,1,0 and the second digit an 8 for orange or 0 for green

The top bits are for wideScreen..inverse,,lowercase. Try it out !

 

 

Good Information....

 

MarkO

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On 1/6/2020 at 10:56 PM, jhd said:

 

Was there any commercial (or even amateur) software that used this mode? 

 

I am unsure if I like it more or less than the standard green screen. Neither is choice is great. 

 

Yes I thought it was cool for a text adventure:

 

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If you change the poke to &HFF22 to &H70 you'll get inverted (light text on dark) instead of light background with dark text.

 

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