Read-only memory test method, and device for carrying out the method

In addition to the actual processor, microcontrollers generally also contain a program memory designed as read-only memory. In order to be able to check the contents of the program memory without making this content available outside the microcontroller, the setpoint data of the program is supplied externally and the comparison is carried out within the microcontroller. According to the invention, a small test program is provided in the microcontroller for this test, expediently in an additional read-only memory, which is active in the test mode and carries out the test. As a result, in addition to the memory for the test program, virtually no additional hardware is required for this test.