The semiconductor device in which reading and writing of data can be
accurately performed by preventing malfunction even when a selection of
address delays. The semiconductor device has three factors of a data
holding unit, a precharge unit and a delay unit. The data holding unit
includes a plurality of memory cells. The precharge unit includes a
precharge potential line, a precharge signal line and a plurality of
switches. The delay unit includes a plurality of transistors. In
addition, it has one or both of an address selecting unit having a
column-decoder and a row-decoder and a display unit having a plurality of
pixels, as well as the three factors.