A semiconductor display device which can suppress the drive frequency
while increasing the number of gray scales. According to the
semiconductor display device, a plurality of pixels can be selected per
row by a first scan line driver circuit, the plurality of pixels can be
selected per row by a second scan line driver circuit, writing of a first
video signal to the row selected by the first scan line driver circuit is
controlled by a signal line driver circuit, writing of a second video
signal to the row selected by the second scan line driver circuit is
controlled by the signal line driver circuit, and using respective
selection circuits included in the first and second scan line driver
circuits, the output from the second scan line driver circuit to the
plurality of pixels can be set at high impedance while the row is
selected by the first scan line driver circuit, or the output from the
first scan line driver circuit to the plurality of pixels can be set at
high impedance while the row is selected by the second scan line driver
circuit.