A computer program product in a computer-readable medium for use in a microcontroller-based control system in a programmable logic integrated circuit device is disclosed. The computer program product comprises first instructions for initializing the device, second instructions for reading programming data from a data source external to the programmable logic integrated circuit device, third instructions for transferring the programming data into control elements internal to the programmable logic integrated circuit device. Provision is made for fourth instructions for saving at least a part of the internal logic state of the user logic programmed into the programmable logic integrated circuit device into a non-volatile memory block and for fifth instructions for restoring at least a part of the internal logic state of the user logic programmed into the programmable logic integrated circuit device from a non-volatile memory block. The programmable logic integrated circuit device, comprises a microcontroller block and a programmable logic block with programming circuitry, and has a sub-bus which couples the microcontroller block to the programming circuitry.