Dual CPU on-chip-debug low-gate-count architecture with real-time-data tracing

A microcontroller application monitoring system, comprising:

• a Host computer that runs monitor software for an application system in which a Target microcontroller is embedded;
• a Link microcontroller that is a chip of the same design as a Target microcontroller chip and that is alternatively configured as the Link microcontroller, wherein the Link microcontroller includes:
• a) means for running an interface translator program between the Host computer and the Target microcontroller;
• b) means for communicating with the Target microcontroller using a fast 2-wire communication interface;
• and
• c) means for communicating with the Host computer through a general communication interface such that the Link microcontroller shields the Target microcontroller and the Link microcontroller appears to the Host computer as having a general purpose interface;
• wherein the Target microcontroller includes:
• a) means for running an end user application program without restriction;
• b) means for communicating with the Link microcontroller using a fast, 2-wire communication interface;
• and
• c) means for running a special debugging program called a monitor.