about DCD verification(i.mx6)

[宗標廖]

Hello, community

I have some questions about DCD verification.

In IMX6SDLRM 8.5.4.3 ECSPI Boot, there is description as bellow.

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The boot ROM code copies 4 KB data from EEPROM device to the internal RAM. If

DCD verification is successful, the ROM code copies the initial 4 KB data, as well as the

rest of the image extracted from application image, directly to the application destination.

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Q1)

Could you tell me the detail of DCD verification(How is the verification done)?

Q2)

If the DCD verification is failed,what is the next action?

Thank you!

ZongbiaoLiao

[qiang_li-mpu_se]

For Q1, you can think the DCD is a data struct, and it has some special tags. The boot ROM will verify if it is a valid DCD struct for boot up.

For Q2, that means boot failure happens, it will swicth to serial download mode.

[Yuri]

Hello,

  Section 8.6.2 [Device Configuration Data (DCD)] of the RM describes

possible restrictions for DCD commands in NOTE comments.

In particular, Table 8-33 (Valid DCD Address Ranges) provides allowed

addresses to access.

    If the DCD verification is failed :
1) Redundant Boot  is activated (if enabled) ;

2) SD/MMC Manufacture Mode is entered (section 8.11 SD/MMC Manufacture Mode) ;

3) Serial (USB) bootloader is entered.

Have a great day,
Yuri

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