Sure, I am glad to do that. But I don't have a20 so I can only carry out this experiment on a10 currently.
On Tuesday, June 17, 2014 3:36:21 AM UTC+8, Siarhei Siamashka wrote: > > On Mon, 16 Jun 2014 06:03:18 -0700 (PDT) > Tong Zhang <[email protected] <javascript:>> wrote: > > > Hi Siarhei, > > > > Thank you for your reply. > > > > I attached a ds18b20 thermal sensor on top of a10 to measure the > > temperature. > > > > And I drew a graph using following formula (temp_data-1447)*/20. It > seems > > that the two line correlate well on the right(minutes after attached) > > rather than the left(not long after attached). > > > > < > https://lh3.googleusercontent.com/-VX9j3c6EWnk/U57oUI6gB-I/AAAAAAAABxM/7FfvvskqmzQ/s1600/sensor.png> > > > > Thanks. While you are at it, can you try to do the measurements for a > wider range of temperatures? And report the actual numbers for a few > points. So that we can calculate the correlation coefficient and find > reasonably accurate linear approximation coefficients. > > You can heat up the CPU by using the cpuburn-a8 program as explained at: > http://linux-sunxi.org/Hardware_Reliability_Tests > > And if you set the userspace cpufreq governor, then you can manually > change the CPU clock frequency. Basically, first you let it idle for > a while, then get the readings from the a10 temperature sensor (the > raw number) and the ds18b20 thermal sensor. As a next step you set > some low CPU clock frequency, run cpuburn for a while and also record > the sensor information. Repeat this until you reach the 1GHz CPU clock > speed. > > If you also have some A20 hardware, doing the same for it would be > very interesting too. > > This would allow us to finally resolve the temperature sensor > calibration mysteries. > > -- > Best regards, > Siarhei Siamashka > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" 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/d/optout.
