On Mon, 16 Jun 2014 06:03:18 -0700 (PDT) Tong Zhang <[email protected]> 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.
