[Oberon] RGB display in Oberon RISC5

[thomas.kral at email.cz]

Hi Joerg,

Using palettes would utilise memory while offering more colours. This would 
also possibly bring it close to Ceres-2. The two procedures bellow taken 
from Display.Def of Ceres-2 project, do they imply the use of a colour map 
(palette)?

PROCEDURE SetColor*(col, red, green, blue: INTEGER);
PROCEDURE GetColor*(col: INTEGER; VAR red, green, blue: INTEGER);

>From H/W point of view, coudl it  be more difficult to implement in Verilog?

Tomas


---------- Původní zpráva ----------
Od: Jörg Straube <joerg.straube at iaeth.ch>
Komu: ETH Oberon and related systems <oberon at lists.inf.ethz.ch>
Datum: 20. 4. 2016 8:30:11
Předmět: Re: [Oberon] RGB display in Oberon RISC5

"Hi Magnus

Thx for preparing VID.v
As the original ProjectOberon has only 1M of memory, it's a pity to waste 
25% of your 4 bit color layout. Basically, we could use 16 colors instead of
8.
Instead of mapping the bits directly to RGB, I would rather use the 4 bits 
as index into a color palette.

Display.Mod has to be adapted accordingly.

Jörg

> Am 18.04.2016 um 21:59 schrieb Magnus Karlsson <magnus at saanlima.com>:
> 
> I have made an updated version of VID.v with support for an RGB video 
buffer.
> 
> The video buffer is now 4x larger (about 40% of the total 1 MB RAM) and 
video refresh will use up about 40% of the memory bandwidth.
> 
> See http://saanlima.com/forum/viewtopic.php?f=14&p=1786#p1783 for Verilog 
code and bit files for Pepino_LX9 and Pepino_LX25.
> 
> Magnus
> --
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