Test mode matrix circuit for an embedded microprocessor core
First Claim
1. An integrated circuit comprising:
- at least one microprocessor;
a plurality of I/O circuits coupled to a plurality of I/O pads, wherein the plurality of I/O circuits comprise a plurality of I/O drivers and I/O receivers;
a logic circuit; and
a switch means coupled between the microprocessor and the logic circuit, wherein the switch means operates in one of a plurality of mutually-exclusive states, and wherein the switch means routes the microprocessor operational signals to the logic circuit without passing through any I/O drivers that are coupled to I/O pads on the integrated circuit and without passing through any I/O receivers that are coupled to the I/O pads in a first of the plurality of states, routes the microprocessor test signals from the plurality of I/O circuits to the microprocessor in a second of the plurality of states, and routes the logic test signals from the plurality of I/O circuits to the logic circuit in a third of the plurality of states.
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Abstract
A test mode matrix circuit in an integrated circuit switches signal lines internal to the integrated circuit in a manner that allows an embedded microprocessor within the integrated circuit to be fully functionally tested using standard test vectors applied to the integrated circuit, and which allows for debugging the code written for an embedded microprocessor core by connecting an in-circuit emulator (ICE) to the integrated circuit. The test mode matrix circuit operates in a number of mutually exclusive modes, each of which is suitably selected via control signal inputs to the test mode matrix. The test mode matrix circuit couples signals from the embedded microprocessor to the application-specific logic without passing through off-chip drivers/receivers. Multiple microprocessors and corresponding test mode matrices may also be implemented on the same integrated circuit.
48 Citations
10 Claims
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1. An integrated circuit comprising:
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at least one microprocessor; a plurality of I/O circuits coupled to a plurality of I/O pads, wherein the plurality of I/O circuits comprise a plurality of I/O drivers and I/O receivers; a logic circuit; and a switch means coupled between the microprocessor and the logic circuit, wherein the switch means operates in one of a plurality of mutually-exclusive states, and wherein the switch means routes the microprocessor operational signals to the logic circuit without passing through any I/O drivers that are coupled to I/O pads on the integrated circuit and without passing through any I/O receivers that are coupled to the I/O pads in a first of the plurality of states, routes the microprocessor test signals from the plurality of I/O circuits to the microprocessor in a second of the plurality of states, and routes the logic test signals from the plurality of I/O circuits to the logic circuit in a third of the plurality of states. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for testing an integrated circuit comprising the steps of:
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providing a microprocessor on the integrated circuit; providing a logic circuit on the integrated circuit; providing a plurality of I/O circuits on the integrated circuit that are coupled to a plurality of I/O pads on the integrated circuit, wherein the plurality of I/O circuits comprise a plurality of I/O drivers and I/O receivers; providing switch means coupled between the microprocessor and the logic circuit, wherein the switch means operates in one of a plurality of mutually-exclusive states, and wherein the switch means routes microprocessor operational signals directly to the logic circuit without passing through any I/O circuits in a first of the plurality of states, routes microprocessor test signals to the microprocessor in a second of the plurality of states, and routes logic test signals to the logic circuit in a third of the plurality of states; routing the microprocessor test signals from an external tester that is coupled to at least one I/O pad; and applying test vectors to the microprocessor through the switch means. - View Dependent Claims (10)
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Specification