Question about Internal Boot-Pins BOOT_CFG[0:15]

[tinogörke]

Hello,

i have a question about BOOT_CFG[6:4] Pins from ref-manuel imx8m-mini. 

How can i choose a different bus-width for SD-Card (1/4-Bit ) and eMMC  (1/4/8-Bit)?

Thanks

[AldoG]

Hello,

From the reference manual of the i.MX 8MM page 815 and 816

Hope this helps,

Best regards,

Aldo.

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

[tinogörke]

Hello Aldo,

the table 6-42/6-43 is for using fuses.

I wanna use only GPIO boot overrides (BOOT_CFG[4:6]) to change bus width for SD-Card or eMMC.

At this point the table 6-19 is a bit unclear for me.

Best regards,

Tino

[AldoG · Accepted solution]

Hello Tino,

Yes indeed this table is related to the fuese map, but the definition of the bits used for BOOT_CFG[4:6] are the same even if you are using the GPIO:

For SD/eSD it only use BOOT_CFG[4] for bus width, bits 5 and 6 are reserved

0 - 1 bit

1 - 4 bit

As for MMC/eMMC it uses the 3 bits

000 - 1 bit

001 - 4 bit

010 - 8 bit

011 - reserved

100 - reserved

101 - 4 bit DDR (MMC 4.4)

110 - 8 bit DDR (MMC 4.4)

111 - reserved

Just like in the table above.

Hope this helps,

Best regards,

Aldo.