PURPOSE: To reduce crosstalk at the border part between the upper and lower screens of an LCD with simple circuit configuration by programming data in a blanking period from outside.

CONSTITUTION: When data '1' are used for a background, '1' is written in a register 111 previously and then display data '1' and blank data '1' are equalized to each other. Namely, when the same data as the data of the background data is written in the register 111, the data never change at the border between a blank line and a display line, so the crosstalk between a 200th and a 201th line is reducible. Consequently, the crosstalk at the border part between the upper and lower screen of the LCD can be reduced with the simple circuit configuration.