On 10/12/2016 03:54 AM, Terry Raymond wrote: > Hi Gerrit, > > Are you referring to the actual data pins that solder in or are socketed. > the transistor is way small though? I'm talking about the structure on the die shot I supplied. If you put pinout of SID and die shot side by side, you can easily tell which pads are what. > I was looking at the larger 3 squares at the bottom, wow . The squares are the pads where the bonding wires are connected. The drivers on the pads of the data lines are the large comb like structures next to them. The ADC pads have something similiar, but MUCH smaller. > 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 :) The die is about 4 x 4 mm if I remember right. Gerrit > > Terry Raymond > > On Tuesday, October 11, 2016, Gerrit Heitsch <firstname.lastname@example.org > <mailto:email@example.com>> 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 > <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 15:02:18
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