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  1. Gianluca85

    [Solved] SDRAM parameters

    Understood. In reply to Chrisf as well, yes, I was indirectly asking if anyone knows where I could find a complete and clear documentation. I am new with Allwinner so I may have missed something. I understand the licensing terms issue, however I do not see how this may prevent them to release new hard coded parameters every time the RAM technology improves IF the RAM vendor is the same. The ticket is closed for me.
  2. Gianluca85

    [Solved] SDRAM parameters

    Hi, my board is using AllwinnerH3 CPU with Samsung SDRAM. Reference design is the nanopi-m1-plus board. We know believe the issue is hardware related because the board works well with one RAM chip however it has the issue observed above if two RAM chips are used. Schematic is 100% the same of the nanopi-m1-plus, it should be EMC on power supply or wrong characteristic impedance when address lines split. However it would be nice to understand how to program the SDRAM controller of this CPU. So far the documentation from Allwinner is disappointing on this point and RAM settings are for the 1333 speed grade while now we have 1800 speed grade however we cannot get any benefit until clear and complete specifications are released.
  3. I am using Armbian 4.14 kernel on a custom board. As soon as the boards boots up I get a lot of oops and memory address fault. Software works on another board that use same memory and mtest always succeeds on faulty board even with complementary patterns. I have got the feedback that this new memory belongs to the newest revision level so SDRAM parameters needs to be updated. However I am using the 4.14 kernel so .fex configuration is not taken into consideration by the kernel, although initialize the SDRAM controller is bootloader->SPL's duty. Anyone knows how to update SDRAM parameters without using .fex config file or compile u-boot and SPL to open and initialize SDRAM controller according to its settings? I realize that problem may be poor PCB layout, however I will be safe if I can compile according to the new instructions and show the result. Thank you.