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Palette

Submitted by VELESOFT on Sun, 2006-04-23 20:35.


Sam Coupé | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8

The Coupé’s palette is 128 colours of which 16 can be chosen (MODE1,2&4) or 4 in MODE3 - see Screen Modes.

The palette can be altered on a per-line basis using the line interrupts in MODEs 2-4 to give multiple colours on screen or to produce effects in the border, see Fred 41 menu for a good example.

Originally the machine was to have 64 colours due to a shortage of pins on the ASIC, see Hardware Bugs and Limitations but intervention by Bo Jangeborg whilst writing Flash! upped it to 128:

“I convinced them to do away with the hardware flash in the high colour modes. That allowed for a significantly larger pallet. I think it went from 64 to 128 colours. That also allowed me to transfer some pictures from the Atari without too big a degradation.”

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ooops no delete comment

Submitted by rogerjowett on Tue, 2009-12-15 15:23.

no way of getting back to the page of a list we have been looking at either
or expalantion why the list has 123456 pages when teh list is alhpabetical wouldnt letters be better then we might be able to navigate a bit easier say goto letter g etc instead of having to remember which page it was on
does site use itu t v44?

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line interrupt

Submitted by rogerjowett on Tue, 2009-12-15 15:24.

can line interrupt change a palette colour
how many times could this occur on a single scan line please?

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Palette change

Submitted by stoned on Thu, 2010-01-21 22:26.

Yes you can use line interrupt to change palette colour.

After a little test I have found you can change a palette cell up to 9 times in a scan line but only once before your out of border area and the last change will only effect the last few pixels. If you can write code in external memory you can change the colour 3 times in the border area and up 18 times in the line.

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dma is supposed to be 10 times faster than z80

Submitted by rogerjowett on Tue, 2010-06-29 13:06.

how many palette changes per line could dma handle please
is there a dma compatibel with the mayhem accelerator or the internal processor ripout velesoft method - if the ram mounted on the processor ripout method is fast enough to keep up with an accelerated processor could it have a dma on there too
woudl the processor and dma need to take turns using the bus or is there like the ez80190 with two dma and an asynchronous bus preventing processor halts during dma data tranfers
please help
anyone got retro x to save an hdf file for atom lite in sim coupe convert avi video to sam please
im using windows media player fullsc reen rez of 320x 200 then using debut to capture desktop screencast video to 256x192 retro wont accept a 512x192 avi file virtual dub converts to old avi or segmented
retro x converts to tap file but is unwatchable even in the tpa viewer that comes with retro x
dunno how to put a tap file into simkoop please

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