CIRCUIT INTEGRE A SECURITE D'ACCES AMELIOREE

The invention relates to integrated circuits, and especially circuits whose security against fraudulent use it is desired to ensure. The circuits in question are microprocessor circuits comprising a programmable memory (12), a non-volatile programmable memory (16), an input-output port (18) and a register (RS) memorising the signals from detectors (C1 to C4) of abnormal conditions. This register is accessible by the microprocessor. Means are provided for checking the state of the register immediately before any write or erase operation of the programmable memory and immediately before any data transmission towards the outside by the input-output port, and means for interrupting the operation of the microprocessor if the checking discovers abnormal conditions.