art;FIG. 9 is a timing chart for illustrating the operations of the switches at the time of A/D conversion according to the prior art;FIG. 10 is a timing chart for illustrating the data transmission at the time of A/D conversion according to the prior art; andFIG. 11 is a diagram illustrating a prior art using an A/D converter.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTAn apparatus for detect