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Old 30 June 2020, 18:12   #1
JuanLuis
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Trying to show 256 colors AGA images

I have shown an 32 color OCS image on screen without problems, but I was unsuccessful with AGA colors. The image is shown with incorrect colors.

I am switching palette bank setting 3 MSB in BPLCON3 in order to set palette color entries beyond 31 and I'm using LOCT=1 in order to set less significant nibbles of palette color entries.

- Is it needed setting anything more to change palette colors in AGA or setting BANKx and LOCT in BPLCON3 is enough to set COLORxx registers properly?

WinUAE debugger doesn't show palette bank switching or color nibble selection with 'e' command.

- Does WinUAE debugger support palette switching and color nibble selection?

When I'm showing 320x200 AGA images...
- ... is it needed to set FMODE to 3 (BPAGEM=BPL32=1, Bitplane Fetch by 8 bytes, double CAS)?

Thanks in advance.
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Old 30 June 2020, 18:43   #2
mcgeezer
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Quote:
Originally Posted by JuanLuis View Post
I have shown an 32 color OCS image on screen without problems, but I was unsuccessful with AGA colors. The image is shown with incorrect colors.

I am switching palette bank setting 3 MSB in BPLCON3 in order to set palette color entries beyond 31 and I'm using LOCT=1 in order to set less significant nibbles of palette color entries.

- Is it needed setting anything more to change palette colors in AGA or setting BANKx and LOCT in BPLCON3 is enough to set COLORxx registers properly?

WinUAE debugger doesn't show palette bank switching or color nibble selection with 'e' command.

- Does WinUAE debugger support palette switching and color nibble selection?

When I'm showing 320x200 AGA images...
- ... is it needed to set FMODE to 3 (BPAGEM=BPL32=1, Bitplane Fetch by 8 bytes, double CAS)?

Thanks in advance.
When you run 'ea' in WinUAE are you colours loaded in the registers correctly?

You don't need to set anything in FMODE.

Also check you have BPLCON0 set correctly for 8 planes.
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Old 30 June 2020, 21:11   #3
JuanLuis
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Quote:
Originally Posted by mcgeezer View Post
When you run 'ea' in WinUAE are you colours loaded in the registers correctly?

You don't need to set anything in FMODE.

Also check you have BPLCON0 set correctly for 8 planes.
I have just found the error. It was a problem skipping color registers. Now I can view the image with 256 colors without problems.

However, if I set FMODE to 3 instead of 0 the image is shown misaligned. Should I modify DDFSTRT, DDFSTOP with FMODE set to 3?

I would like to use the maximum bandwidth of AGA.

Thanks McGeezer.
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Old 30 June 2020, 21:31   #4
mcgeezer
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Quote:
Originally Posted by JuanLuis View Post
I have just found the error. It was a problem skipping color registers. Now I can view the image with 256 colors without problems.

However, if I set FMODE to 3 instead of 0 the image is shown misaligned. Should I modify DDFSTRT, DDFSTOP with FMODE set to 3?

I would like to use the maximum bandwidth of AGA.

Thanks McGeezer.
You need to compensate your modulo for x4 DMA fetch.

For a standard 320x200 display you could use $38 to $B0.

Set your modulo to what is required then subtract 8.

Here's an abstract from the link I provide below on AGA programming.

*******************************************************************************
Bplmod: The modulo is usually in aga mode the same as in normal mode minus 8.
So if your normal modulo = 0 then the agamodulo is -8. (if you use FMODE=3!)
if you use FMODE =$2 then the modulo is -4.
*******************************************************************************


http://www.amigacoding.com/images/9/97/RandyAGA.txt
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Old Yesterday, 07:43   #5
JuanLuis
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It works fine with module -8. Now I can see the image with 256 colors and FMODE=3.

Thanks McGeezer.
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