System and method for testing on-chip modules and the interconnections between on-chip modules

A method for testing on-chip modules and interconnections between those on-chip modules, comprising:

• receiving a mode select signal, the mode select signal indicating either input test mode or output test mode;
• capturing an output of a first on-chip module in response to the mode select signal indicating output test mode;
• receiving a test signal in an input scan cell;
• forwarding the test signal from the input scan cell to an output scan cell coupled to an input of a second on-chip module in response to the mode select signal indicating input test mode;
• and
• forwarding the test signal from the output scan cell to the second on-chip module input in response to the mode select signal indicating input test mode.

A system for testing the operation of on-chip modules and the interconnections between those on-chip modules, comprising:

• a plurality of component modules which are part of an integrated circuit formed on a semiconductor chip wherein some of the inputs and outputs to the plurality of component modules exist on the boundary of the integrated circuit;
• a plurality of output scan cells coupled to the outputs of component modules which do not exist on the boundary of the integrated circuit, each of the plurality of output scan cells operable to capture an output signal from the component module to which it is coupled;
• a plurality of input scan cells, the plurality of input scan cells providing test input signals to component modules which do not have inputs existing on the boundary of the integrated circuit, the test input signals used to verify the proper operation of the component modules, the test input signals used to verify signal paths from the plurality of output scan cells to the inputs of the component modules, each of the plurality of input scan cells coupled to one of the plurality of output scan cells such that the test input signal can be forwarded to the component module via the output scan cell;
• a plurality of mode select signals, each of the plurality of mode select signals coupled to a corresponding output scan cell and indicating either input test mode or output test mode.