METHOD FOR EVALUATING NONVOLATILE STORAGE ELEMENT AND DATA PROCESSOR USING IT

PURPOSE:To evaluate a data holding characteristic without giving stress to a nonvolatile storage element, by executing a superficial writing to the nonvolatile storage element, reading it and comparing it with writing data. CONSTITUTION:For example, in a writing from a microprocessor CPU to a storage area M0 or to a register RG, a pre-writing is executed. By shortening a writing time or by lowering a writing voltage, the prescribed superficial writing is executed. The writing data held by the microprocessor CPU and read data are comparing and when the decision of the comparison is defective, an access is executed again to the preliminary register RG and the same decision is executed. Then, the practical writing is executed to accompany an additional writing to the register RG to have a satisfactory holding characteristic. Thus, since the data holding characteristic is evaluated and only the superficial writing is executed, the stress to the nonvolatile storage element can be reduced.