System on a chip with an integrated configurable safety master microcontroller unit

A system on a chip (SoC) comprising:

• a first domain comprising a first processor configured to boot the SoC, and a first debug subsystem;
• a second domain comprising a second processor, the second domain configurable as either an external safety domain, an internal safety domain, or a general-purpose processing domain;
• and
• isolation circuitry between the first domain and the second domain;
• wherein during boot-up of the SoC, the first processor provides code to the second domain which, when executed by the second processor, configures the second domain as either an external safety domain, an internal safety domain, or as a general-purpose processing domain;
• and
• wherein the isolation circuitry is configured to isolate the second domain from the first domain when the second domain is configured as an external safety domain, and to allow the second domain to monitor the first domain when the second domain is configured as an internal safety domain, and to allow the first domain to control the second domain when the second domain is configured as a general-purpose processing domain.