DS3231 I2C Problem

Hello,

not sure if I put this in wrong section, but anyway...

I recently bought a DS3231 module (which has EEPROM IC in one PCB also). For some reason I cannot manage to communicate with the IC using I2C protocol.

I had tried the I2C protocol on other I2C devices such as MPU-9150 and it worked.

So I decided to test the hardware, and found out between SCL-VCC or SDA-VCC, it gives a resistance reading of around 2.8 KOhms... Usually with I2C, I use 4.7 kOhms.

I know that the board has 4.7 kOHms array resistors built-in, and I did not put an external pull-up.

So is this an hardware problem? If so I will remove the pullup

Hello and welcome,

ZS-042 module? Do you power the module with the arduino or with the backup battery?

For the latter, removing the resistor array (the one closest to the center of the board) and enabling the arduino's internal pullup solved the problem for me. I didn't have problems when powering the module with the arduino, only when on battery.

This topic may help: http://forum.arduino.cc/index.php?topic=346940.0

Thanks for replying

yes it is ZS-042 (Blue PCB).

Regarding power, battery was installed since shipping, then I plug the VCC-GND from arduino without removing the battery (which I believe won't be a problem since the battery should stick there on power down anyway)

Haven't tried to remove the resistors... will do that later.

I have checked on the topic you mentioned, but seems they got no trouble for communications... only about interrupt pin

Have you tried using a library example sketch to communicate, instead of your own software?