A D/A converter has a serial interface. Of the sets of the data representing
multiple
control signals output from latch circuits, the data representing input data, the
data representing strobe signal, and the data representing clock signal are supplied
to the D/A converter. A mask circuit is provided in the path supplying the strobe
signal. When a parity detection circuit detects a transmission error, the mask
circuit masks the strobe signal to be supplied to the D/A converter, thereby preventing
the D/A converter from outputting an analog output signal corresponding to the
input data.