Cpu minimum frequency ?

General Discussion
1

How can be set the minimum frequency of 480Mhz ? I need it for reliable reading db18s20 Dallas temperature sensor.

2

Depends on the device, but this should do it:

echo 480000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
3

Thank you, I’m using Orange Pi Zero. I found that sometimes I cannot read from /sys/bus/w1/devices/28*/w1_slave and it is probably due to low frequency of cpu causing bug in temperature computation.

Is there any other workaround to make readings from Dallas ds18b20 1-wire thermometer reliable all the time ?

4

Wish I could help, but I have absolutely no idea, sorry. Hopefully someone else with experience can chip in here.

5

I have similar issues with FriendlyArm’s NanoPi NEO Air: http://www.friendlyarm.com/Forum/viewtopic.php?f=47&t=393

Is there any other workaround to make readings from Dallas ds18b20 1-wire thermometer reliable all the time ?

It’s still a workaround: Whenever reading the DS18B20 (in my case every 60 seconds), i start a second process which consumes cpu time. The python code can be found here: raspberry/libs/sensors/DS1820.py at master · thomaspfeiffer-git/raspberry · GitHub

Additionally i ordered a 1-wire to I2C device (DS2482-100). This might be a working work-around as well.

Thomas

6

Hello,
Now the v156 of DietPi as an new config option :
DietPi-Config | Performance > CPU: Added support for setting minimum CPU frequencies.
Best regards,