RTC For IMX8 in Ixora board

Technical Support
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1

Dear Team,

I am using Apalis Imx8 along with IXORA board v 1.2A to run a qt based UI Application.

From the Schematics I Inferred, Ixora board can support 2 RTCs (Internal and External), by switching between R40 and R39. How ever in the actual board its observed that R39(Contrary to schematics) is used, Hence from schematics its inferred The Hardware setup uses internal RTC ( Rather than M41T0M6).

I am running embedded v(3.4) in the Ixora board.

I had tested the RTC Status with environment mentioned above and its working fine.

Do we need any modification in the image to switch between the RTC Source or does imx8 automatically identify the RTC source based on R39,R40 population.

Thanks and Regards,
Aneesh

2

Hi @knaneesh,

Thanks for writing to Toradex Community.

Regarding your query, R39 and R40 is used to decide which RTC will be powered by external battery(Coin Cell) in case main power is turned off. By default it is external RTC which will be powered by external BAT.

Next regarding how to select RTC to be used please see below link

Let me know if you face any issue in same.
Best Regards
Ritesh Kumar

3

Hi @knaneesh !

Were you able to solve your issue?

Do you have any news on this topic?

Best regards,
Henrique

4

Dear henrique,

Not really.

Hello Ritesh,

The board contained R39 as default, but since it was required to use External RTC (M4T10). After changing we tried to set date time using following commands
timedatectl set-time
hwclock -w

But when power cycling the board when we try to get time using timedatectl command. Its showing following error

timedatectl
Failed to query server: Failed to read RTC: Invalid argument.

Further i added following rules

KERNEL==“rtc1”, SUBSYSTEM==“rtc”, DRIVER==“”, ATTR{name}==“m41t0”, SYMLINK=“rtc”, MODE=“0666”

But this creates no change.

Could you suggest a resolution.

Thanks in advance

5

Hi @knaneesh ,

Just for clarification, which Resistor do you currently have mounted on the Ixora?

And which RTC do you want to use? As we understand you would like to use the external one ?

Best Regards
Kevin

6

Dear Kevin,

We have R39 Removed. R40 Placed. And we are planning to use the external one(M41T0M6)

Regards,

7

Hi @knaneesh ,

Thanks for the clarification.

I am not quite sure what version you are referring to. What BSP do you have installed on the module?

Furthermore, would it be possible for you to attach the device tree here?

Best Regards
Kevin