A device for supervising ports of an integrated circuit is arranged for exchanging information with a central processing unit of an integrated circuit and for communicating with ports of the integrated circuit. The device comprises address decoding means, access control means, and parity controlling means. The device for supervising ports comprises read-back information means arranged for receiving input from the port and for passing that input to the parity control means and in that the address decoding means, the access control means, the read-back information means and the parity controlling means are arranged to be operative in a background loop wherein a range of port addresses is monitored. The read-back information means reads data and one or more parity bits stored on ports with an address in the range and the parity controlling means performs a parity check on the one or more parity bits stored on the ports.