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m62.c:

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* fixed wrong resistor value (22K to 2.2K) - verified on spelunkr and kidniki hires pcb pictures
* Changed resistor network calculation based on assumption that cs line is active either on tiles or sprites color prom.
This commit is contained in:
Couriersud 2008-01-27 00:53:25 +00:00
parent 34c714b281
commit 5c8a08ce3c
1 changed files with 40 additions and 6 deletions
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46
src/mame/video/m62.c
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@ -51,6 +51,40 @@ static INT32 spelunkr_palbank;
-- 1 kohm resistor -- RED/GREEN/BLUE -- 1 kohm resistor -- RED/GREEN/BLUE
bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE bit 0 -- 2.2kohm resistor -- RED/GREEN/BLUE
The resistor values could be verified on a hires pcb picture (spelunkr).
The schematics also exhibit one pulldown for the sprite color guns.
Since only either the sprite or tile gun is active, i.e. the other is
in tri-state, this pulldown resistor also applies to the tile color guns.
Which of the sprite/tilemap color guns is in tri-state mode is determined
by a pal. There is no good dump of this pal. If both sprite and tilemap
should be active (i.e. not in tristate) at a time, this would due to the
pulldown resistor have slightly darker colors as a consequence.
This can explain the spelunkr bug m62_0116u4gre.
The kidnike bug kidniki0104u3gre even looks worse and may imho only explained
by subpixel effects, i.e. delays when switching the proms into tristate.
Since there are no dumps of the "priority" pal, the above is
speculation.
Priority PAL
The PAL is at location 4F on the "T" board. The PAL's input are 3 bits
from tilemap 0, 3 bits from tilemap 1 and A11-A14:
CB0A => 7 20 GND
CB1A => 8? 14 ==> PROM CS
CB2A => 9 P 19 ==> Tilemap select 0/1 / to connector
C14A => 12 A 11 <== Sprite priority out / to connector
C13A => 4 L 18? ==> Sprite priority in / to connector
C12A => 5 10 GND
C11A => 6
CB0D => 1
CB1D => 2
CB2D => 3
***************************************************************************/ ***************************************************************************/
@ -58,9 +92,9 @@ static const res_net_info m62_tile_net_info =
{ {
RES_NET_VCC_5V | RES_NET_VIN_TTL_OUT, RES_NET_VCC_5V | RES_NET_VIN_TTL_OUT,
{ {
{ RES_NET_AMP_NONE, 0, 0, 4, { 22000, 1000, 470, 220 } }, { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } },
{ RES_NET_AMP_NONE, 0, 0, 4, { 22000, 1000, 470, 220 } }, { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } },
{ RES_NET_AMP_NONE, 0, 0, 4, { 22000, 1000, 470, 220 } } { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } }
} }
}; };
@ -69,9 +103,9 @@ static const res_net_info m62_sprite_net_info =
{ {
RES_NET_VCC_5V | RES_NET_VIN_TTL_OUT, RES_NET_VCC_5V | RES_NET_VIN_TTL_OUT,
{ {
{ RES_NET_AMP_NONE, 0, 470, 4, { 22000, 1000, 470, 220 } }, { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } },
{ RES_NET_AMP_NONE, 0, 470, 4, { 22000, 1000, 470, 220 } }, { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } },
{ RES_NET_AMP_NONE, 0, 470, 4, { 22000, 1000, 470, 220 } } { RES_NET_AMP_NONE, 0, 470, 4, { 2200, 1000, 470, 220 } }
} }
}; };