SSP0/1-SD/MMC/eMMC Boot: SSP_SCK polarity setup issue in ROM

[michaelkoelbl]

Hi,

as I had problems booting from NANDFlash

(Problem in programming NAND flash with MfgTool on iMX28 EVK)

I decided to switch to booting from SD-card, as this worked fine on the IMX28EVK. After having built up my own hardware I tripped over the SSP_SCK polarity problem mentioned in the iMX28 Chip Errata http://cache.freescale.com/files/32bit/doc/errata/IMX28CE.pdf?fpsp=1&WT_TYPE=Errata&WT_VENDOR=FREESC...

I tried different SD cards and it seems that all are working. MfgTool sometimes makes trouble when connecting the board to the PC's USB but after pressing the Reset button on my hardware the second run works and therefore I think that's not a SD card problem.

My question is: has anyone positive or negative experience with this issue?

The Errata sheet says there is no fix scheduled. I can't belive that. Having such a bug and booting from SD is really not exotic! I can do the workaround with the EEPROM when making a redesign of my hardware but it doesn't make me happy to have an additional EEPROM which in additon has to be programmed before.

[mihnen]

We ran into the same issue with a custom board and yes there really is no fix scheduled! What we ended up doing was dropping in an inverter (NC7SZ04P5X) on the spi clock as well as providing a 0 ohm to bypass it just in case this was fixed in the future. This setup is working just fine for our board.

[michaelkoelbl]

Hello Matt,

thanks für your suggestion. I thought about that, too. It's fine to hear that it works.