Patent Number: 6,311,303

Title: Monitor port with selectable trace support

Abstract: An integrated circuit includes a monitor port, several circuit modules, and a selection circuit that selects which of the circuit modules drives internal signal through the monitor port. A debugging process can observe the internal signals at the monitor port to identify problems in the integrated circuit. In one embodiment, the selection circuit includes a trace bus that runs serially from the monitor port to each circuit module. Each module has tri-state buffers that connect the module to the trace bus. Alternatively, the selection circuit includes a multiplexer with input ports coupled to the modules. A trace select register controls which module drives the monitor port, and control registers or the current operation of each module select which set of internal signals the module applies to the tri-state buffers. Any of large number of internal signals can be selected and observed by programming the trace select register and the configuration registers for the modules. In one embodiment, the integrated circuit is a host adapter that includes modules operating in different clock domains.

Inventors: Gates; Stillman F. (Los Gatos, CA), Devanagundy; Uday N. (Hayward, CA)

Assignee: Adaptec, Inc.

International Classification: G01R 31/28 (20060101); G01R 31/3185 (20060101); G01R 031/28 (); G01R 031/08 ()

Expiration Date: 10/30/2018