Hi all
I have some question about BOOT_CFGx registers in i.MX6DL.
I can't understand the purpose and how to select it.
So please tell me following questions.
Q1."SD Calibration Step inn P.335 Table5-5 BOOT_CFG2[7:6]"
What is the purpose of SD Calibration Step ?
I can't imagine the calibration for SD.
What kind of information do you choose based on ?
Q2. "DDR Memory Map default config in P.335 Table5-5 BOOT_CFG3[5:4]"
What is the purpose of the register ?
What kind of information do you choose based on ?
Q3."DLL Override in P.335 Table5-5 BOOT_CFG2[2]"
What is the Boot ROM default value ?
What kind of information do you choose based on ?
Ko-hey
Hello,
1.
According to section 8.5.3.3 (SD, eSD, and SDXC) of i.MX6 S/DL RM,
The UHSI calibration start value (MMC_DLL_DLY[6:0]) and the step value
(BOOT_CFG2[7:5]) can be set to optimize the sample point tuning process.
It is needed to support high speed modes. Please look at section 67.5.3.2.4
[DLL (Delay Line) in Read Path] of the RM.
2.
DDR Memory Map default option relates to memory configuration; the MMDC
supports two channel LPDDR2.
3.
SD calibration is performed by ROM code, users typically don't need to override
this value, When BOOT_CF2[DLL ovirride] bit is set, the value at associated
DLL_DLY value is applied. Refer to the item 1.
Have a great day,
Yuri
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Hi Yuri Muhin
Sorry for late reply.
I have an additional question about No.3.
> SD calibration is performed by ROM code, user typically don't need to override
> this value, When BOOT_CF2[DLL ovirride] bit is set, the value at associated
> DLL_DLY value is applied. Refer to the item 1.
Could you give me an example situation when user need to override the value ?
Ko-hey
Hello,
from the design checklist at HW_Design_Checking_List_for_i.MX6DQP6DQ6SDL
(sheet "issue hunting"):
0x450[10](BOOT_CFG2) DLL Override: 0 - Boot ROM default 1 - Apply value per fuse field MMC_DLL_DLY[3:0] Default setting in ROM is incompatible with current PCB design. |
Set 0x450[10](BOOT_CFG2) to "1", and try to find proper setting through fine tune related FUSE. |
Regards,
Yuri.
Hi YuriMuhin_ng
How to judge the proper setting ?
Is it judge by waveform ?
I can't understand whether what is proper or not.
Ko-hey
Hello,
Here situation is similar to memory calibration: it is needed
to get range of the values, where operations are good for
several boards and choose, say, the median value.
Regards,
Yuri.