RTC issue-pca8565

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RTC issue-pca8565

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zhaocq
Contributor II

we use external RTC PCA8565, the bellow issues please help to resolve:

1) boot stage,we find the error log

   

[ 0.118882] rtc-pca8565 2-0051: Power loss detected, invalid time
[ 0.118987] rtc-pca8565 2-0051: rtc core: registered rtc-pca8565 as rtc0

[ 0.119585] rtc-pca8565 2-0051: Power loss detected, invalid time
[ 0.119591] rtc-pca8565 2-0051: hctosys: unable to read the hardware clock

2) after boot, we use command:i2cget -f -y 2 0x51 0x02

we can get the data(no i2c error), but the register 0x02 the highest bit is 1 always.

Could you tell me that is why, thanks in advance!

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi zhao

for power loss issue one can check hardware using documentation below:

PCA8565 datasheet

https://www.nxp.com/docs/en/data-sheet/PCA8565.pdf 

User Manual

https://www.nxp.com/docs/en/user-guide/UM10301.pdf 

software patch

rtc: add support for rtc NXP pca8565 - Patchwork 

Best regards
igor
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1,368 Views
zhaocq
Contributor II

hi igor,

Thanks for your reply.

we have measure our power voltage and clk, they are both no problem. Also our i2c is ok.

but the register values sometimes report error, for example , the register 0x07 stands for month value, 

we get the value is 0(1~12 reasonable).

I want to know before using pca8565_rtc_read_time, if i should set the time firstly, using pca8565_rtc_set_time?

Now we can not see pca8565_rtc_set_time call when reboot.

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