An example of a circuit of the block diagram for pin output of the RL78 is shown. In general, port output and SAU output, TAU output, and other output are assigned to each pin. In the RL78, there is normally no built-in register for switching between these outputs. These outputs are controlled (switched) by the value of the output latch of the port. In the block diagram shown below, SAU output (alternate function 2) has an AND relationship with the output latch output of the port. After that, it has an OR relationship with TAU output (alternate function 3). That is to say, to use output from the TAU you should set the output latch of the port to 0, and fix the output that has the AND relationship to low level. This will make it possible to output TAU output from the pin (at this time, if another function is assigned to the same pin, make that output low level). Thus, the output of the desired alternate function is selected by setting the output latch of the port and fixing the output level of the remaining alternate function.