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pcf85263a not counting

Question asked by Gabriel Gh on Nov 7, 2018

I'm using the PCF85263A RTC with BeagleBone Black board running linux: debian jessie. I have connected it to my i2c-1 line and am able to see it at address 0x51. I can do i2cdump and see registers values. I'm trying to get it to start by following the steps in datasheet section 8.2.6:


- Set STOP bit to HIGH 1 in register 2E

- Clear the prescaler by writing 0xA4 to register 0x2F ( i do not see confirmation on this register when I try to read it back but I assume it works since when I write 0x2C in this register it resets all registers to Default values)

- Set time registers

- Set the STOP bit to LOW 0 in register 2E (according to datasheet time is supposed to start counting from this point)


When I do the rest of the steps and set STOP bit back to 0 it do not see the values in the registers increment at all? what am I missing? I'm not using any drivers for this currently since I could only find drivers for pcf8563 in my 4.4-ti kernel.


Also what about the OS bit in the register 0x01 (100th second)? It mentions that I should clear it so the oscillator is running but when I try to set it to 0 it retains its prev value of 1(register value of 0x80). How can I clear it? Is this what is causing the clock not to increment?


What should I do to get this running properly?