DS3234 RTC not working correctly on 3.3V

I have a DS3234 RTC wired up to an Uno and it all works fine using the 5V output from the Uno to the Vcc on the DS3234, using SPI natively (no library). The datasheet says typical voltage is 3.3v so I used that output from the Uno and I can set the time but it never increments and the interrupt doesn't work. All the clock functions only work on Vcc=5V.

I took out the Vcc and GND from the Uno and put the battery in and it's the same. Clock won't increment and interrupt doesn't work. It only works on 5V Vcc from Uno.

If I read the time in the loop it's all 0s. If I don't read the time, it's stuck at the time I set it to in setup.

Is there something I'm missing? I don't have pullup resistors in the circuit, just wires from chip to Uno. Are the wires too long? They are standard breadboard wires about 6in long.

thanks.

I took out the Vcc and GND from the Uno and put the battery in and it's the same. Clock won't increment and interrupt doesn't work. It only works on 5V Vcc from Uno.

@codebrane

Your topic was Moved to it's current location / section as it is more suitable.

Could you also take a few moments to Learn How To Use The Forum.

Other general help and troubleshooting advice can be found here.
It will help you get the best out of the forum in the future.

Why, if you have 5 volts and run the UNO with that, are you trying to run the RTC on 3.3 volts?

Are you using a DS3234 chip, or a module? If it is a module, it may not be designed to run on 3.3 volts. If it’s a bare chip you playing with, it’s easiest to use the same Vcc voltage for everything.

When half your circuit is 5 volts and another half 3.3 volts, somewhere along the way you (or the module designer) have to account for the different logic levels. There are a variety of ways of doing this.

a7

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.