IC2 / DS3231 / DS3232 / Wire.write / Control Register 0x0E

Projects Networking, Protocols, and Devices
1

Sorry for my stupid English… I’m playing with a RTC (DS3231 / DS3232) and don’t understand working with “Wire.write” on I2C with the control register.

The control register 0E contains several information
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE

And an all (untested) examples I found there was always unchecked the content written one byte.
Wire.beginTransmission(DS3232_I2C_ADDRESS);
Wire.write(0x0E); // move register pointer to control register
Wire.write(0); // set to 1Hz
Wire.endTransmission();

In Datasheet only BIT3 and BIT4 controls frequency. The other Bytes are for several other tings.
In my opinion it is necessary first read, then mask and rewrite. Or I’m wrong?
Also in no examples is checked the return code of Wire.EndTransmission. Why?

Perhaps somebody can tell me why I’m wrong.

2

In my opinion it is necessary first read, then mask and rewrite. Or I'm wrong?

No, it's not necessary as the power-on default is defined and if you know how to set all bits you're allowed to do it in one write.
The value 0 simply sets the frequency to 1Hz and enables the square wave output on the SQW pin, leaving the rest of the bits on the default.

Also in no examples is checked the return code of Wire.EndTransmission. Why?

Because many Arduino programmers don't know about the possibility or don't care about error handling.