IMX7 Fuse Register Details.

[gopinathsriniva]

Hello,

I am looking for boot mode and fuse register settings in IMX7 reference manual. I can see the option for selecting SD and eMMC port in internal boot mode.

BOOT_CFG[11:10] -  USDHC Port Selection

00                            -   USDHC-1

01                            -   USDHC-2
10                            -   USDHC-3
else                         - reserved

But I cannot find the fuse register settings for selecting SDHC ports in fuse mode. I can only see the values for 0x470[7:0] register. (Table 6-11. SD/eSD Boot Fusemap in TRM). 

Can anyone say, how eMMC port selection can be programmed in fuse mode?  I mean, in IMX6, I can find these details in 0x450[15:8] register in Table 5-8. MMC/eMMC Boot Fusemap. 

Cheers,

Gopinath

[gusarambula]

Hello Gopinath Srinivasan,

In order to select eMMC boot in fuses you would need to select to boot from eMMC on BOOT_CFG[15:12] and then the port on BOOT_CFG[11:10].

 

Some boot options have to be selected for eMMC also, like the USDHC1/2 IO voltage so please also keep this in mind.

This format may be a bit cleaner than on the i.MX6 documentation where some fuses are defined for the same interface when they are shared by different configurations, but it's confusing when you're used to the i.MX6.

I hope this helps!

Regards,

[gopinathsriniva]

Hi,

In IMX6, to fuse the SOM for booting from eMMC, writing below values to the OTP registers (OTP_CFG4 and OTP_CFG5) does the job. 

<!-- fuse the SOM -->
<CMD state="Updater" type="push" body="$ echo 0x4060 > /sys/fsl_otp/HW_OCOTP_CFG4">fuse prog 0 5 0x4060</CMD>
<CMD state="Updater" type="push" body="$ echo 0x00000010 > /sys/fsl_otp/HW_OCOTP_CFG5">fuse prog 0 6 0x00000010</CMD>

Can I ask you, how these two registers are mapped to BOOT_CFG ? Because I cannot find more details about this OTP registers related to BOOT MODE? Because I am trying to map the same to IMX7. 

Thanks,

Gopinath S

[gopinathsriniva]

I checked with offset in both IMX7 and IMX6. So In IMX7, BOOT_CFG offset is  470h offset. So I need to write the One time program register "OCOTP_BOOT_CFG0" for boot fuse settings.

 Can you please conform my understanding is right?

Thanks,

Gopinath S