On Wed, 20 May 2015 05:03:00 -0700 (PDT) sufi al hussaini hassani kamili raheemi <[email protected]> wrote:
> Hi Siarhei Siamashka, > > I tried your prototype image v5 > <https://github.com/ssvb/sunxi-bootsetup/releases/tag/20141215-sunxi-bootsetup-prototype> > with > some of the A20 and A10 boards I have > (i.e. A20-OLinuXino_MICRO, A10-OLinuXino_LIME, and some BPis), to make sure > the image on SD card was written alright; and it booted fine (both on debug > UART and HDMI). Thanks for trying it and confirming that it works fine on the known good boards. > Next, I tried it with my board, but It still gives me the same error: > > U-Boot SPL 2014.10-01707-gc4fca89 (Feb 10 2015 - 04:03:30) > DRAM:Timeout initialising DRAM > > > resetting ... This all makes me think that the hardware problems are the most likely culprit. > Based on the "Timeout initialising DRAM" error message, this is often > > encountered when you have configured U-Boot for the wrong SoC type. > > Is your board really using specifically the *A20* SoC? > > I can confirm that the board is actually using A20 (Dual-core T). OK. > I was wondering if it would be a good idea to replace my RAM with a > 'K4B4G1646D' from a spare BPi I have, and give it a try. Yes, you can try to replace the RAM chip (if you are a hardware person and know how to do this). Your current DRAM chip has 1Gb density, which is rather low. And I'm not aware of any other Allwinner devices using such chips. however the chips of 1Gb/2Gb/4Gb densities differ only by the number of address lines and everything else is similar. So personally I don't think that it should be a problem, but still I can't be completely sure either. It is possible to search for "A20_DDR" or "Allwinner A20 SDRAM Support List" keywords in the Internet and find some sort of a compatibility list of the DRAM chips. There is only one 1Gb chip listed there, and it is x8 (yours is x16). Are you using a single DRAM chip now or a pair of them for getting the full 32-bit bus width? As for the troubleshooting ideas, you can also check voltages. Is this board using the AXP209 PMIC or relies on some fixed voltage regulators? Also I'm not a hardware person myself, but I heard that the DRAM tracks routing on the PCB tends to be rather difficult and there are some strict length and impedance matching requirements. -- 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.
