Need help in programming SPI based DAC9881

Nitesh,

In terms of the digital interface the DAC9881 is a fairly straight forward device to use as there are no additional internal registers to configure outside of the DAC data register.

The only mechanic perhaps worth discussing is the LATCH pin for synchronous or asynchronous update modes. The device features what we call a double-buffered shift register for the digital inputs, so basically on a write to the DAC data register the data goes to a sort of 'holding' register until LDAC is taken low. When LDAC goes low the data is copied from the 'holding' register to the DAC data register and the output will update. Alternatively LDAC may be held low, in this case data goes directly to the DAC data register.

For the SPI interface your MCU will need SPI, you may use either positive or negative polarity SPI, the rising edge is the critical edge.

I hope this helps, let us know if you have further questions.