47.6.9.4 Differential Mode

DAC0 and DAC1 can be configured to operate in differential mode, i.e. the combined output is a voltage balanced around VREF/2, see also the figure below.

In differential mode, DAC0 and DAC1 are converting synchronously the DATA0 value. DATA0 must therefore be a signed value, represented in two’s complement format with DATA0[11] as the signed bit. DATA0 has therefore the range [-2047:2047].

VOUT0 is the positive output and VOUT1 the negative output. The differential output voltage is therefore:

V_{OUT} = \frac{DATA 0}{2047} \times VREF = (V_{OUT 0} - V_{OUT 1})

DACCTRL0 serves as the configuration register for both DAC0 and DAC1. Therefore DACCTRL1 does not need to be written.

The differential mode is enabled by writing a '1' to the Differential bit in the Control B register (CTRLB.DIFF).

Figure 47-4. DAC Conversions in Differential Mode