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). Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
