Hi Gerrit, Are you referring to the actual data pins that solder in or are socketed. the transistor is way small though? I was looking at the larger 3 squares at the bottom, wow . Is the SID wafer about the size of a match head about, just amazing so much could fit on a small wafer, SID on Steroids :) Terry Raymond On Tuesday, October 11, 2016, Gerrit Heitsch <gerrit@laosinh.s.bawue.de> wrote: > On 10/11/2016 06:10 PM, Jim Brain wrote: > >> >> The SID POT ADC circuitry needs to drag the line hard to ground for 256 >> cycles. NMOS would easily handle this, but it must be a pretty hefty >> transistor to ensure it can overcome the current coming from the paddle >> resistor. I don't see such a transistor on the 6581 die shots, but it >> must be there. What should I look for? >> > > When looking at > > http://mail.lipsia.de/~enigma/mos6581r4/full_q30.jpg > > the paddle inputs should be the 2nd and 3rd pad from the bottom on the > left side of the die. Between them is a mirrored structure which should be > the measuring circuit. > > Close to each pad, I can see something that looks like a transistor that > connects the pad to the GND line. But it's a lot smaller than the drivers > for the data pins. > > The paddle resistors are 500K max, but I don't know what their minimum > value is. The schematics suggest that it's zero, but that would be more > than any NMOS driver can handle... > > Gerrit > > > > > > > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing listReceived on 2016-10-12 02:00:07
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