Microcontroller system for safety-critical motor vehicle systems, comprising a plurality of subsystems (A, B), which are arranged on a common chip, at least one of which subsystems (A, B) is of a multi-channel design, wherein the microcontroller system is configured to carry out a plurality of operating modes, wherein the subsystems (A, B) - in a first operating mode are operated independently of one another and communicate with one another by means of a chip-internal interface (A27, B27), characterized in that the microcontroller system comprises a second operating mode and the subsystems (A, B) have different system clock domains in the first and second operating mode, wherein during communication with the non-local resources (A13-1, B13-1,..., A18) one subsystem is synchronized with another (A, B) by means of synchronization units (A28, B28), wherein - in the second operating mode a) at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) or b) at least one of the subsystems (A, B) is operational and at least a further one of the subsystems (A, B) is inactive or c) in the second operating mode at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) and the at least one subsystem (A, B) is operational and at least the further one of the subsystems (A, B) is inactive. - in a first operating mode are operated independently of one another and communicate with one another by means of a chip-internal interface (A27, B27), characterized in that the microcontroller system comprises a second operating mode and the subsystems (A, B) have different system clock domains in the first and second operating mode, wherein during communication with the non-local resources (A13-1, B13-1,..., A18) one subsystem is synchronized with another (A, B) by means of synchronization units (A28, B28), wherein - in the second operating mode a) at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) or b) at least one of the subsystems (A, B) is operational and at least a further one of the subsystems (A, B) is inactive or c) in the second operating mode at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) and the at least one subsystem (A, B) is operational and at least the further one of the subsystems (A, B) is inactive. a) at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) or b) at least one of the subsystems (A, B) is operational and at least a further one of the subsystems (A, B) is inactive or c) in the second operating mode at least one of the subsystems (A, B) is operated by means of provided data transmission means (A25, B26, A26, B26) additionally using non-local resources (A13-1, B13-1,..., A18) of at least one of the further subsystems (A, B) and the at least one subsystem (A, B) is operational and at least the further one of the subsystems (A, B) is inactive.