Part Number: AM3352
Hi,
My customer has an issue with booting from SD Card on MMC0 in their custom board.
The board is based on BeagleBone Green(BBG) and customer copied most of design from BBG.
- DDR and circuit
- SD card circuit
- SYSBOOT setting
- etc.
Then customer uses the same SD card with an image which boot successfully on BBG, but it fails on the customer board (nothing booted).
According to customer observation, only mmc_dat0 signal is toggling during boot sequence compared to BBG (other data signals are toggled).
I think MMCSD boot sequence switches from 1bit mode to 4bit mode if SD card is detected.
(all SD card supports 4bit mode)
If customer connects CCS and loads image via JTAG, the code runs properly, so other parts (clock, power supply, DDR, etc.) should be OK.
Is there any reason why SD card boot fails?
Why the mode cannot switch from 1bit mode to 4bit mode?
Thanks and regards,
Koichiro Tashiro
