Hi, On Thursday, 15.03.2018 at 11:43, Andre Przywara wrote: > > 648 MHz seems to have helped a lot, I've done several warm and cold boots > > and only seen the BUG once so far. Will try lowering the frequency further > > Cool! I see other Allwinner boards using 624 MHz, so that might be a > sweet spot. Alternatively you could also try 408 MHz, which should work > everywhere.
Still running at 648 Mhz and haven't seen the BUG again, but am only moderately loading the board with building and running self-tests for the project I'm working on [1] out of tmpfs. > I really wonder if this is about the PCB delay lines. So far we were > getting away with the Pine64(?) values for other boards as well, but the > Olimex board might be substantially different in the PCB layout. A friend here mentioned that just from eyeballing the board the DRAM lines seemed "too simple" to him compared to other ARM boards he's used. > > I've found what looks like a datasheet for the DRAM part at [2]; I know > > nothing about DRAM initialisation so have no idea where to find the correct > > frequency to use in that document. > > Thanks, that very helpful! So it looks like these are actually even > 800MHz capable chips. But either this requires some tuning on the PCB > delays or the voltage is wrong (as on the Pine64, where we fix this). > I will add some code to print the actual DRAM voltage in ATF, will send > you something for testing later tonight. Thanks! -mato -- 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.
