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hello ,
this is my first try on the MAME emulator project.
Board info :
CPU : MC68000 8mhz
Video : MC6845
Audio : AY3-8912
I have done for the moment :
1. mapping of the board
2. skeleton of the driver (software run, but still some i/o todo)
3. dump of ROM ,NVRAM, emulation of PAL
currently , I am lost in the decoding of the video section
VIDEO RAM work with 2 BYTES
1 ATTRIBUTE BYTE (color + bank select)
1 TILE BYTE
there is a BYTESWAP at the output of ROM GFX plus
a funny use of clock in the RASTER ROW.
I have attached a DUMP of the videoram and the schematic
if someone can help me.
thanks
Yves
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Re: video tilemap problem
[Re: yves]
#281666 - 04/06/12 06:54 AM
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Personally I never use tiles, I'd rather output the pixels myself. This gives you full control of the display. Take a look at the zrt80 driver in MESS. This shows the basic concept for outputting lines of dots on the screen. You will need to change the 'for' loop to pick up every 4th byte ( change x++ to x+=4 ).
Notice where 8 pixels are output, bits 7 to 0, left to right. Since your character generator has a different order, put the order here. This saves you the overhead of doing BITSWAP8.
Once you have text on the screen, then you can start thinking about implementing the attributes.
> hello ,
>
> this is my first try on the MAME emulator project.
> Board info :
> CPU : MC68000 8mhz
> Video : MC6845
> Audio : AY3-8912
>
> I have done for the moment :
> 1. mapping of the board
> 2. skeleton of the driver (software run, but still some i/o todo)
> 3. dump of ROM ,NVRAM, emulation of PAL
>
> currently , I am lost in the decoding of the video section
> VIDEO RAM work with 2 BYTES
> 1 ATTRIBUTE BYTE (color + bank select)
> 1 TILE BYTE
>
> there is a BYTESWAP at the output of ROM GFX plus
> a funny use of clock in the RASTER ROW.
>
> I have attached a DUMP of the videoram and the schematic
> if someone can help me.
>
> thanks
>
> Yves
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Re: video tilemap problem
[Re: yves]
#281684 - 04/06/12 11:38 AM
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> hello ,
>
> this is my first try on the MAME emulator project.
> Board info :
> CPU : MC68000 8mhz
> Video : MC6845
> Audio : AY3-8912
>
> I have done for the moment :
> 1. mapping of the board
> 2. skeleton of the driver (software run, but still some i/o todo)
> 3. dump of ROM ,NVRAM, emulation of PAL
>
> currently , I am lost in the decoding of the video section
> VIDEO RAM work with 2 BYTES
> 1 ATTRIBUTE BYTE (color + bank select)
> 1 TILE BYTE
>
> there is a BYTESWAP at the output of ROM GFX plus
> a funny use of clock in the RASTER ROW.
>
> I have attached a DUMP of the videoram and the schematic
> if someone can help me.
>
> thanks
>
> Yves
Nice... haven't seen a Winning Touch machine in many years - they were once commonplace in Victoria Australia, almost every gaming venue/pub/hotel had one! The games we had down here were all 5- or 10-game multigame units rather than standalone games.
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Re: video tilemap problem
[Re: Robbbert]
#281699 - 04/06/12 04:13 PM
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thanks for your help Rob ,
I have changed my video section to use pixel drawing.
still need to figure out the use of :
1. U14 Rom char Adress A0 ,A1 (connected to clock divider)
2. this would give character of 8x32 ? (why not use Ra0..Ra5)
I doing test for the moment without the attribute Byte.
have a nice week end
yves
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