In some applications, it is necessary to calibrate the module for offset error. This module allows an easy way to do this by providing internal connections from input to VREF or DAC0. To short AD4+ and AD4- to VREF or DAC0, change the CTSD16INCHx setting for each channel to 0x11 for VREF and 0x12 for DAC0. This allows calibration of the CTSD16 input stage by what is measured from the ideal value. The total signal chain offset depends on the impedance of the external circuitry; thus, the actual offset seen at any of the analog inputs may be different.