PCA21125 RTC Get real time

[AshBirari]

Hello NXP,

I am trying to get the real time using RTC PCA21125.Following way I have implemented the RTC interface with AURIX TC389 controller using SPI communication.

Write Command : 0x10

Read Command : 0x90

SPI Configurations  :

    Data width : 8

   Transfer Start : MSB

RTC Initialization :

Configuring Register Control 1 as 0x0C (POR_OVRD = 1, 12_24 = 1)[is this correct way ?]

 Configuring Register Control 1 as 0x00

RF bit of SECOND regirster is always 1 as its default value.

trying to read the Second, Minute, Hour data from the register using SPI commands.

Observed  Values :

Seconds :  0

Minutes : 19

Hours : 12

[TomasVaverka]

Hello Ashwini,

I do not fully understand what is the issue you are facing.

I would recommend you to take a closer look at our UM10301, mainly chapters 12.1  - Initialization of the RTC and setting the time, and 6 - Oscillator.

The simplest way to check for oscillation is to use the CLKOUT pin. There should be a 32.768 kHz signal at pin CLKOUT available after power-on. If your design does not include a pull-up resistor to the CLKOUT, then add one temporarily. 

BR, Tomas

[AshBirari]

Thank you for suggesting me the UM10301 user manual. As given in the module, chapter 12.1 table 5 I need to initialize the RTC POR bit of Control register 1 and RF bit of Second register should be cleared. But I am facing issue while clearing POR bit of Control Register 1 and RF bit of Second Register. I am not able to clear these above bits. How can I resolve this issue ?