On Fri, Dec 11, 2015 at 10:41 AM, Sugar Wu <shugeli...@gmail.com> 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? 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 linux-sunxi+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- 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 linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
