Processor including a combined parallel debug and trace port and a serial port

摘要

A processor provides trace capability. Trace information can be provided over a communication port that is operable both as a trace port and as a parallel debug port. The trace port provides trace information indicating instruction execution flow in the processor core. The operation of the communication port as a trace port and as a parallel debug port is mutually exclusive. The parallel debug port provides for transmission of debug information between a debug host controller and the processor. The parallel debug port and the trace port physically share pins. Bus request and grant signals are provided between the parallel debug port and a debug host controller to ensure that collisions do not occur between use by the trace port and the debug host controller. A separate serial debug port is also provided which can be used to enable the parallel debug port.