[email protected] wrote: > I am reading voltages on AIN0 and AIN1, the voltage on the pins is > almost exactly 0.9 volts, I have measured it quite carefully with a > multimeter and this is the voltage I would expect given the dividers > I'm using. > > The raw value from the ADC is 896 (plus or minus a count or two). It > really is reading the voltage as, if I increase or decrease it a > little, the reading goes up and down. > > However this means that the ADC actually has a full scale reading of > only around 1800 for 1.8 volts, that's not a 12-bit ADC it's closer to > an 11 bit one. > > Is the ADC set up so that the reading actually represents the voltage > (i.e. 1800 is 1.8 volts)? > > Anyway I think the specification misrepresents the ADC accuracy. > OK, I found out what was misleading me. The ADC values that I'm seeing are the BBB's "non raw" ones which are scaled to be (as I guessed) the voltage in mV.
However I can find very little guidance on how to read the actual raw values, especially from Python. I want to scale the values myself and using the already scaled 0-1800 values would mean I'm losing a bit of accuracy. Can anyone point me at some Python (or even C if you like) code to read the real, raw, values? -- Chris Green ยท -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
