Method and apparatus for external viewing of an internal bus

摘要

A method and apparatus for viewing the contents of an internal bus (112) external to a integrated circuit (100) begins by providing a integrated circuit (100) which has the internal bus (112). Internal bus is not itself accessible to the external terminals of the integrated circuit (100). When an access on the bus (112) needs to be viewed external to the integrated circuit (100), a control section (120) forces the signals/access on the bus (112) to a second slower bus (114) within the integrated circuit (100). The second bus is coupled to circuitry (160) which is coupled to external terminals so that the external terminals can be used to inspect the contents of the bus (112) by using the bus (114) as an intermediary.