Hello Hans, >> But certainly, having a kernel driver output 0-255 for a voltage input is >> a huge and unacceptable step backwards. Please fix that first and then >> we can talk about the rest. I agree completely. But I have a proposal to solution. All we just need to know is the how many volts are used for one bit. http://www.winbond.com/e-winbondhtm/partner/PDFresult.asp?Pname=926 Some suggestions are here around page 64. And some information are here: + label in0 "CPUcore" + compute in0 @*0.0137 , @/0.0137 + label in1 "DDRVdd" + compute in1 @*0.0137 , @/0.0137 + label in7 "Vdd5V" + compute in7 @*0.0245 , @/0.0245 VCore is often unscaled so this *0.0137 gives for 8bit => 3.4935Vref so 3.5V Rest is simple: just compute the correct divisors for each in0 0.0245/0.0137 is round 2 so 5V might be scaled by 2. I dont know how those values were obtained so I cant do more speculations. Best would be if could measure actual voltage on pin P3REF so pin50 of the chip. Also there is another Vref at pin 72 the datasheet is unclear what pin is used when. If you are measuring please measure actual chip VCC too. (This should be 5V) How to measure: Multimeter 0-5V DC one wire to selected pin, second wire try the black wire of 4 hole power connector. Try not to shortcut the pins around. You can take a needle and glue it with the tape to multimeter probe. Thanks Regards Rudolf
