Technical solutions are described for providing a redundant processor. An example processing unit includes a source processor coupled with a system communication bus via a first communication line; a backup processor coupled with the system communication bus via a second communication line; and an inter-microprocessor communication channel for communication between the source processor and the backup processor. The backup processor monitors for a failure of the source processor by monitoring the first communication line for communication messages being transmitted by the source processor. The backup processor determines a failure of the source processor in response to an absence of the communication messages on the first communication line for a predetermined duration. The backup processor, in response to a failure of the source processor, takes over control of communication of the processing unit by sending a status update on the inter-microprocessor communication channel.