On 2015-12-11 15:49, Chen-Yu Tsai wrote: > On Fri, Dec 11, 2015 at 10:41 AM, Sugar Wu <[email protected]> wrote: >> Hi ChenYu, >> >> I am sorry. >> We just run DDR8 40MHz on A31/A31s with MMC3. >> If you run it with MMC2, it not support DDR8 function. >> You should switch pinmux to MMC3. > > Interesting. Is this a hardware difference between MMC2 and MMC3? > Or is it just signal routing problems? Just a little different. > > Anyway I got DDR8 working on my A31s. Thanks! > >> If you want to try DDR 50, you can improve IO voltage to 3v. >> And, you should set mod clock(in ccmu) and card clock(in mmc controller) in >> following different scenarios: >> a. 8 bit width: >> source clock must be double card clock, it mean CCLK_DIV is 2. >> (Card Clock) = (MMC Module Clock) / 2 > > Yes. I noticed this from the SDK. With this already 8 bit works on A33 / A80. > > I also noticed A33's "new timing mode", but I can make DDR work without it, > using old timing mode. > > > Regards > ChenYu > >> >> b. 4 bit width: >> Card Clock = MMC Module Clock >> >> Best regards >> >> Sugar >> >> On Thursday, December 10, 2015 at 3:17:44 PM UTC+8, Chen-Yu Tsai wrote: >>> >>> Hi, >>> >>> I am working on DDR support for the MMC controllers. >>> Unfortunately none of my boards support signal voltage switching to 1.8V, >>> (and I suspect no boards do), so I cannot try out UHS-1 modes. >>> >>> I have 4 boards that have eMMC chips connected to MMC2. >>> These are the A80 Optimus, Cubieboard4, Sinlinx SinA33, and SinA31s. >>> eMMC DDR 52 is working on all but the SinA31s. The delay values >>> from Allwinner kernel sources do not work. >>> >>> Can Allwinner provide the delay values for A31/A31s MMC2 DDR50? >>> >>> Ongoing work can be found here: >>> >>> https://github.com/wens/linux/commits/sun9i-wip >>> >>> If anyone knows of any boards that support SD card voltage switching, >>> please let me know. >>> >>> Regards >>> ChenYu >> >> -- >> 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.
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