diff options
author | Bryan McPhail <bmcphail@vcmame.net> | 2017-06-27 17:02:07 -0400 |
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committer | Bryan McPhail <bmcphail@vcmame.net> | 2017-06-27 17:02:07 -0400 |
commit | 455fc201af1d74deda8b3defa08cf551d6be2ad3 (patch) | |
tree | eb5677796312ee9fe5ad388a2b661384d6e08600 | |
parent | dad7fca1f75e1d1e6ba766ab15bbe0e4e905a24e (diff) |
Add alternate revision of Cobra Command. Add correct palette weighting for all Dec8 games
-rw-r--r-- | src/mame/video/dec8.cpp | 35 |
1 files changed, 13 insertions, 22 deletions
diff --git a/src/mame/video/dec8.cpp b/src/mame/video/dec8.cpp index 6f44238d372..cf46a380697 100644 --- a/src/mame/video/dec8.cpp +++ b/src/mame/video/dec8.cpp @@ -50,28 +50,19 @@ sprites. Convert the color PROMs into a more useable format. - Real Ghostbusters has two 1024x8 palette PROM. - I don't know the exact values of the resistors between the RAM and the - RGB output. I assumed these values (the same as Commando) - - bit 7 -- 220 ohm resistor -- GREEN - -- 470 ohm resistor -- GREEN - -- 1 kohm resistor -- GREEN - -- 2.2kohm resistor -- GREEN - -- 220 ohm resistor -- RED - -- 470 ohm resistor -- RED - -- 1 kohm resistor -- RED - bit 0 -- 2.2kohm resistor -- RED - - bit 7 -- unused - -- unused - -- unused - -- unused - -- 220 ohm resistor -- BLUE - -- 470 ohm resistor -- BLUE - -- 1 kohm resistor -- BLUE - bit 0 -- 2.2kohm resistor -- BLUE - + Real Ghostbusters has two 1024x8 palette PROM, other games in this driver + use palette RAM. + + Real Ghostbusters, Cobra Command, Gondomania, Oscar at least are confirmed + to use two custom resistor packs marked DECO RM-C3 to convert the digital + palette for analog output. + + Each pack contains two channels with resistor values of 220 ohms, + 470 ohms, 1 kohm, 2.2 kohm and 4.8 kohm, however the highest resistance is + not used as these games are only 4 bits per channel. + + This leads to weightings per bit of 0xe, 0x1f, 0x43, 0x8f. + ***************************************************************************/ PALETTE_INIT_MEMBER(dec8_state,ghostb) |