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Use SQW on PCF8523 Raspberry RTC
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Use SQW on PCF8523 Raspberry RTC

by tjf on Thu Oct 11, 2018 7:32 am

Hi
I bought a PCF8523 and use it as RTC on a Raspberry stretch.
Works as expected. So far so good.
Because the driver has its hand on the PCF8523 I am not able to set an Parameters for the SQW.
How can I set:
Reg 0x02 to 0x42 (enable counter a and INT1)
Reg 0x0F to 0x02 (TAC[1:0] to 01 which means enable timer A count down)
Reg 0x10 to 0 x00 (select 32kHz as TimerA Clock input)
Reg 0x11 to 20 (counter value)

This would result in a SQW Interrupt INT1 every 5 ms, which I would like to use as interrupt in Python.
Both Python and the shell comment report “busy error” when trying to access the PCF8523 because its handled by the RTC driver.
Is there any way to add this values somewhere (e.g. add them to the drivers initialization sequence)?
Thanks for any input and
Best regards
Thomas

tjf
 
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Joined: Mon Sep 04, 2017 6:12 pm

Please be positive and constructive with your questions and comments.