imx7 serial bootloader stuck into sd/mmc manufacture mode

[kriss]

Hi

 I have board with MCIMX7D5EVM10SD and I have problems to get to USB serial downloader.

Details:

eMMC connected to SDHC1

SD1_CD used as uart and is low on boot

BOOT_MODE0 = 1

BOOT_MODE1 = 0

USB_OTG1_ID = floating, 1v8 measured 

So according to manual boot loader should try SD/MMC manufacture mode before USB serial download mode. And I can see with scope this happening. Unfortunately after fail bootloader is not jumping to USB it is keep re-trying SD/MMC for ~100ms and then just stop.

When I make SD1_CD = 1 bootloader just go straight to USB serial and it works fine.

What I'm doing wrong? or is manual correct?

Regards

Krzysztof

[Yuri]

Hello,

i.MX7 uSDHC1 and uSDHC2 are primarily intended to serve as external slots or 

interfaces to on-board SDIO devices, therefore these ports are equipped with

“Card detection” and “Write Protection” pads .. ”.

  So, when using uSDHC1 and uSDHC2 for external slots with “Card

detection” signal, this signal should be grounded, if not used.

  It is needed to have “Card detection” signal for SD boot (for uSDHC1).

Look at Table 6-45 (SD/MMC IOMUX pin configuration) of i.MX 7Dual 

Reference Manual, Rev. 1, 01/2018 about pins, required for boot.

  To check if SD boot card is prepared correctly, can You try "simple" SD boot? 

Regards,

Yuri.

[kriss]

Thank for answer Yuri, 

But my question is: why bootloader is not jumping to USB serial mode when no image found on eMMC device (or eMMC not responding). It should according to manual.

Regards

Krzysztof

[Yuri]

Hello,

  i.MX7 boot ROM tries to read the eMMC as described  in boot chapter of

the Reference Manual (assuming it is bootable) and, looks like, hangs.

Regards,

Yuri.