Testing of memory content

(57) It is the method of testing the memory which carries out engaging of clutch to a summary microprocessor, and is used especially for a smart card. This method includes measuring the output from the memory (2) which is sent with the read-out path (10) accompanied by the predetermined data signal generated externally, and is sent through a port (7) with a read-out path (9). This comparison is performed by the comparison device (3) which may be the microprocessor programmed appropriately, for example. The output from this comparison device (3) is one success/failure collation signal impressed in the port 5. The stored data held in the memory (2) is eternally held like ROM (memory which can be changed), or may be written in in a memory specially because of the use of a test.