Dear Stefano Babic, > On 07/05/2012 09:11, David Jander wrote: > > Dear Stefano, > > Hi David, > > > Yes, but is none of those boards using 3.15 or 3.3V? If they are, those > > bits must be cleared! > > This is a good question - also because SD was tested and it is working > on these cards. I am asking to myself how it can work if voltage is wrong. > > >> At the moment, we have no problems and I can explain why. The only > >> boards setting these pins (for SD card) are mx51evk and vision2. Both > >> are setting PAD_CTL_DRV_VOT_HIGH, and because the define is wrong, they > >> are really setting the pin to low output voltage mode. > > > > AFAIK, most SD-cards need 3.1V or more to work, and the EVK boots from an > > SD card. That means, the rails NVCC_PER15 and/or NVCC_PER17 are probably > > powered from a 3.15 or 3.3V supply, so the HVE bits for those pins must > > be cleared in able to avoid damage (3.3V is what they call "Ultra High > > Voltage"). > > Really I have expected that SD does not work if the voltage is lower as > specified, not that theree is a damage - I can understand this in the > opposite case (setting high voltage when low voltage is required). > > >> For other boards and other pins, voltage is not explicitely set : this > >> means they work in low voltage mode after a reset. > > > > Everyone reading the documentation as it was available before 03-2012 > > would most probably think this is ok, even for 3.1...3.6V powered pins, > > but according to the new documentation, it isn't. So probably many > > boards need to be re-designed or at least u-boot board-code needs to be > > fixed for them. This is a different issue though, and needs to be > > addressed by the different BSP maintainers or board manufacturers. > > I think only u-boot code should be fixed. > > >> To fix arch/arm/include/asm/arch-mx5/iomux.h and synchronize it with the > >> documentation, we need also to change mx51evk / vision2, setting the > >> pins to PAD_CTL_DRV_VOT_LOW, and they will work as now. > > > > ... and probably die. > > well, they will work as now - with low voltage instead of high voltage. > Anyway, I agree that this should be wrong, because when the code was > written was thought that the voltage should be high. > > > The setting is most probably wrong. All we need to do, > > is change the define in the header files, and not touch the mx51evk / > > vision2 BSP files. But the respective maintainers need to be warned > > IMHO. > > Go ahead in this direction. Then we can test on these boards (mx51evk / > vision2 / efikamx), the only ones having these issue).
Respective maintainer just woke up ... just send me the efika patch, I should be able to test ;-) > Best regards, > Stefano Babic Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
