The DACNT register is a 14-bit readable/writeable up-counter that increments on an input clock pulse (The clock source is selected by CKS in DACR). This counter register can be both read and written, and it is used by both channels of the D/A converter. Please note that the value written to this register is the STARTING value for the up counter. It is not necessary to actually read or write the counter during D/A conversion, although users may want to do so for various reasons, such as diagnostics or synchronization. In one of the D/A modes, this counter stops at 0x0003 (i.e., count = 0) after it rolls over. This is advantageous for noise-sensitive applications, since stopping the converter after a single conversion eliminates noise from the fundamental clock. If customers use this mode, though, their analog circuit might need a sample-and-hold circuit after the D/A converter to hold the voltage when the PWM conversion stops.