PURPOSE: To read out only a part of one line of data in a memory cell array by stopping an access at an arbitrary address of a data register performing a serial access and transferring the next data from the memory cell array to the register.

CONSTITUTION: A start pointer 2 retains the address from where the serial access is started from a data register 8, and an address counter 13 consecutively generates addresses according to an input floc. A stop pointer 11 retains an address signal from the address counter 13, a comparator circuit 12 compares the value of the stop counter 11 with the value of the address counter 13, and a selector 9, when it receives the output of the comparator circuit 12, stops the updating of the address where the value of the data register 8 is read out.