MAMEWorld Forums - MAME Artwork: Official

> > It would nice if we could get the lights on top in the artwork Am I correct in
> > thinking that the driver is not set up for them? Can we do it up like the Space
> > Encounters kinda thingy?
>
> Haven't checked the driver yet, but it could be like Super Chase or Space Encounters,
> yes.

According to the APB schematics:

writes to address 0x187C on the 6502 cpu bits 2 and 3 control the red and blue lights on the top of the machine (I'm not sure which bit controls which light, but bit 2 is "LED 1" and bit 3 is "LED 2")
The lights are driven through a triac board (which often has faults, causing one or both of the lights to be stuck on or off).
other bits of the register at 0x187c control the squeak (720khz vs 640khz) clock to the tms5220c speech chip, and what mode the LETA analog to digital converter chip is in.

The function in MAME which handles writes to 0x187c (switch_6502_w) in atarysy2.c (around line 391) only handles the squeak writes to tms5220c clock control; it totally ignores the writes which control the LETA RESOL quadrature resolution control pin or the LEDs. This obviously needs to be fixed/hooked up before the artwork flashers can ever work.

(not to mention that the LETA chip emulation in atarysy2.c, rampart.c, blstroid.c and offtwall.c is sort of nonexistent, really more HLE than emulation; the inner workings of the chip are explained on JROK's site here: http://www.jrok.com/project/leta/index.htm
of particular interest is the explanation of the function of the TEST pin which is actually used on at least the 2 player joystick versions of rampart to read the joysticks THROUGH the LETA chips! RESOL's function is also explained there.)

LN

"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"

Edited by Lord Nightmare (02/02/12 08:20 AM)