Thanks for testing. On Sun, Jul 15, 2012 at 11:27:11PM +1200, Tom Parker wrote: > Jacob: > Measure with resistance sensor, we find that the trace drops off the > bottom of the screen at 6k??. It seems that the gain slider is a > position control, not a gain control as in audio mode, this > doesn???t seem to be explained in the documentation on wiki.sl.o. > The position control can be used to position zero on the screen. > > Shorting the input yields -10?? which is a little surprising as > negative resistors are rare beasties.
The zero voltage point of the input channel won't always be zero in the digital data. This is specified in the datasheets for the chips. Measure would need to learn the offset, with some sort of calibration button. This has always been the case, but the offset varies across laptops. You might find other laptops have other offsets; displaying something other than -10. p.s. Jacob is not in http://wiki.laptop.org/go/OLPC_New_Zealand/XO_inventory -- James Cameron http://quozl.linux.org.au/ _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
