Hi,
The customer found a SD card which didn’t become 1111b on MMCHS_PSTATE [23:20] when the signal voltage was changed to 1.8V by AM574x.
Could you tell them what is the required procedure other than the default setting of speed class (set SDR12) ?
They’ve already implemented referring to P7151 in AM574x TRM.
SD #1 : Set speed class as SDR12 just before confirming MMCHS_PSTATE [23:20].
As a result, the voltage of DAT[0] was operating at 0V.
When MMCHS_PSTATE [23:20] is checked, those are ALL 0 and the mount fails.
SD #2 : Set speed class as SDR12 just before confirming MMCHS_PSTATE [23:20].
As a result, the voltage of DAT[3] - DAT[0] were changed to 1.8V and operated.
After that, if MMCHS_PSTATE [23:20] is checked, they are ALL1 and it is proceeded according to the flow.
Used SD cards : UHS supported SD card (Speed Class 1)
Device : AM574x
IDE : CCS v8
Compiler : GCC GNU v6.3.1(Linaro)
Board : AM57 Custom Board
SW : pdk_am57xx_1_0_11
OS : bios_6_76_00_08
Tools : XDCTools 3.50.3.33
ICE : Lauterbach
Regards,
Hideaki
