An electronic circuit includes a plurality of configurable cells configured by a control circuit such as a test access controller when it receives a mode command signal: either in a functional state in which the configurable cells are functionally linked to logic cells with which they co-operate to form at least one logic circuit if the mode command signal is in a first state or in a chained state in which the configurable cells are functionally connected in a chain to form a shift register, if the mode command signal is in a second state. The electronic circuit also includes a detection circuit laid out to produce an active state signal if it detects a chained state of the configurable cells while the controller receives the mode command signal in the first state.