On 06/02/2017 01:46 AM, Bertho Stultiens wrote: > Problem 1: > The RPI3 has dynamic frequency scaling activated by default > (ondemand governor). This makes the Pi hop between 600MHz and 1.2GHz > core frequency. Very annoying and makes realtime rather > unpredictable.
There are actually two lines that must be added to rc.local: echo -n 1200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq echo -n performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor The first one forces to hop to 1.2GHz. The current cpu frequency, apparently, may otherwise hang onto the 600MHz value (in .../cpu0/cpufreq/cpuinfo_cur_freq). > Problem 2: > The SPI peripheral input frequency appears to be hopping between > 400MHz and about 250MHz. This probably originates somewhere in the > Linux kernel as the kernel is in charge of clock-generation. There may be an interaction with the power supply and the frequency-lock of one of the BCM283[567] PLLs. Several power-glitches caused the system to crash after I installed a full graphical desktop version. It turned out I was using a cheapo usb supply with bad regulation. The problems seem to stop now that I have attached a bench-PSU set to 5V directly on the 40-pin header's 5V input. I needed to increase the voltage to 5.1V after the red LED still was blinking once in a while (probably indicating too much noise on the power line with my long wires without decoupling capacitor on the end). It may be worth checking the actual 5V line for noise too. -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
