| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a serial semiconductor memory in which data on a specific bit are read out directly. SOLUTION: When a semiconductor memory is instructed to carry out an operation in a bit-column specification readout mode by common data out of input data Din , a control circuit 3 judges it, and control signals Csw , Cwx , Csf , Cad and a memory access request signal Cas are generated. By following the control signals, a changeover circuit 8 connects an external data bus S0 to a data line Sb , and a data selector 7 connects one out of parallel data lines S0 to S7 designated by the control signal Cmx to the data line Sb . In addition, an address counter 5 sets the memory address of a memory map 1 which is designated by address data out of the input data Din . As a result, data in units of bytes which are accessed by a memory are transferred to the data selector 7 via a bidirectional shift register 6, and only data Dbt on a designated specific bit are sent out to an external data bus S0 as output data Dout .</p> |
