ELECTRICALLY PROGRAMMABLE READ-ONLY MEMORY

摘要

The present read-only memory frauds are evaded by fabricating, internally to the memory, the different potentials which the memory uses to check the selected memory points. The verification of the writing of an information at one point is obtained by subjecting said point to a calibrated selection voltage to which an outside operator cannot have access. Said calibrated voltage is provided by a generator-multiplier (14). The latter yields into one or a variety of calibrators (18) to produce all the useful voltages. Reading and writing orders are then given to a switching circuit (74) which causes the corresponding application of those calibrated voltages. An outside operator cannot enter into the memory spurious signals at level to modify the meaning of the contents of recorded information.