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Re: tms5200 clock frequency
05/18/10 10:07 AM
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> > > I am measuring clocks on my Money Money pcb but I have a problem with the tms5200 > > > clock. > > > > > > The frequency counter measure a clock of 565khz instead of 640khz as stated in > > mame. > > > The problem is that there isn't a resonator near the tms5200. The clock pin is > > > connected to some resistors, capacitors and transistors. it is possible also that > > the > > > trace goes to the 3.58mhz osc but I can't follow anymore the traces. > > > > > > I believe the clock is made on the pcb with discrete components or discrete > > > components are used as divisors > > > In this case, what value should be put in mame? > > > > 640khz. Try measuring the ROMCLK pin of the chip, it should measure 160khz (it is > the > > main clock / 4). trying to directly measure the clock at the OSC pin, given that > > money money uses the tms5200 in RC clock mode and not external clock mode, will > > always throw off the result, usually slowing down the clock speed significantly. > This > > is true for all chips which use RC clocks. > > > > The original message was from over two years ago... oh well, it'll help someone, I > guess... > > - Stiletto
Indeed. I just watched kold666's youtube video (http://www.youtube.com/watch?v=cd9CIy6h8M4&fmt=18) of his money money pcb too, and I think 640khz may be too slow (or someone messed with the frequency pot on the pcb sometime since the factory.) The 'tromba' channel and the other correct analog sounds (currently incorrect in mame) can also be heard.
LN
"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"
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