9.4.1 Toggle Mode

Each DAC in the device can be independently configured to operate in toggle mode. A DAC channel in toggle mode incorporates two DAC registers (Register A and Register B) and can be set to switch repetitively between these two values. The DACx1408 toggle mode operation can be configured to introduce a dither signal to the DAC output, to generate a periodic signal or to implement ON/OFF signaling, among some examples.

To update the toggle registers the following sequence should be followed:

1. Set DAC channel in synchronous mode and disable toggle mode for that channel
2. Write the desired Register A value to the DAC data register
3. Issue a DAC trigger signal to load Register A
4. Write the desired Register B value to the DAC data register
5. Enable toggle mode to load Register B

Once both registers are loaded with data, any of the three TOGGLE[2:0] pins can be used to switch those DACs configured for toggle operation back and forth between the contents of their two DAC specific registers by using an external clock or logic signal. A TOGGLE pin logic low updates the DAC output to the value set by Register A. A logic high updates the DAC output to the value set by Register B. The three TOGGLE[2:0] pins give the DACx1408 the option to operate with up to three toggle rates.

Additionally, the device can be configured for software controlled toggle operation by setting the SOFTTOGGLE-EN bit. In this mode, any of the three AB-TOG[2:0] bits can be used as a toggle control signal. Setting the ABTOG bit to 1 enables Register B and clearing it to 0 enables Register A.