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correct fuses programming to boot from nand

Question asked by Diego Perez on Nov 7, 2017
Latest reply on Nov 14, 2017 by Diego Perez

Hi,

 

My target is boot from NANDFLASH, the chip is MT29F8G08ABACAH4-IT:C. So, I have to program the fuses in BOOT_CFG1 and BOOT_CFG2, as table 8-10 of the reference manual show. I would like to be sure, before programming fuses because I only have a few prototypes of my custon imx6solo board.

 

I paste an image with the values I think are correct squared in red color.

 

 

 

  • BOOT_CFG1[7]: Obviously this bit need to be 1 to indicate boot NAND.
  • BOOT_CFG1[5]: I don’t understand this bit, ¿What is the value that I need to put in?
  • BOOT_CFG1[4]: I understood this fuse is for config IO pad settings, so for now I am going to leave as 0.
  • BOOT_CFG1[3:2]: I only have one chip in mi design, so this fuse will be 00.
  • BOOT_CFG1[1:0]: Row Address Bytes. I don’t understand this bit, but the “kobs-ng” command in linux say that “row_address_size = 3”, if this info is related whit this fuse I think the value need to be 00.
  • BOOT_CFG2[7:5]: I don’t know what is my optimal value, and I don’t understand these fuses. ¿Are related with BOOT_CFG1[5]?
  • BOOT_CFG2[4:3]: For now I leave these fuses as 00, But I think it could be 10 since “kobs-ng” repeat 4 times the FCB structure.
  • BOOT_CFG[2:1]: These fuses need to be 01 since the nand flash datasheet says that chips has 64 pages per block.
  • BOOT_CFG2[0]: I don’t understand this fuse, but for now I leave as 0.

 

Assuming RAW mode, 16 GPMICLK cycles, reset time 12ms, the values for BOOT_CFG1 and BOOT_CFG2 are:

BOOT_CFG1

Bit position

7

6

5

4

3

2

1

0

Value=0x80

1

0

0

0

0

0

0

0

 

BOOT_CFG2

Bit position

7

6

5

4

3

2

1

0

Value=0x02

0

0

0

0

0

0

1

0

 

Using uboot command to program fuses:

=>fuse prog 0 5 0x00000280

 

Questions:

  1. Is it necessary program some fuse in BOOT_CFG2 or BOOT_CFG3, or other fuse to boot form my nand?
  2. Is the fuse uboot command correct (fuse prog 0 5 0x00000280)?
  3. Please, could you give me the values for fuses that I don’t understand? And a brief explication:
  • BOOT_CFG1[5]
  • BOOT_CFG2[7:5]
  • BOOT_CFG1[1:0]
  • BOOT_CFG2[0]

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