| 摘要 |
PURPOSE:To keep the secret for the memory contents of the ROM by coding the reading output of the ROM by the optional code decided by the user and then decoding it by the above optional code at the CPU. CONSTITUTION:The logic operation is given to output information d1-dN sent from ROMA via each bit signal decided by the user within memory elements M1- MN and exclusive logic sum gates G1-GN. And the logic output given from each gate receives the logic operation via the signal same as each bit signal in M1- MN within memory elements M1'-MN' at the exclusive logic sum gates G1'- GN' to be returned to original output information d1-dN. |
