Datasheet

First, be sure to call begin(addr) where addr is the i2c address (default is 0x62, if A0 is connected to VCC its 0x63).

Then call setVoltage(value, storeflag) to set the DAC output. value should range from 0 to 0x0FFF. storeflag indicates

to the DAC whether it should store the value in EEPROM so that next time it starts, it'll have that same value output.

You shouldn't set the flag to true unless you require it as it will take longer to do, and you could wear out the EEPROM

if you write it over 20,000 times.

Increasing the speed

One thing thats a little annoying about the Arduino Wire library in this case is it is set for 100KHz transfer speed. In the

MCP4725 library we update the speed to 400KHz by setting the TWBR

TWBR = 12; // 400 khz

You can speed this up a bit more, if you'd like, check the ATmega328 datasheet for how to calculate the TWBR