Identifying A Signal On A Printed Circuit Board Under Test

• US 20110291688A1
• Filed: 05/24/2010
• Published: 12/01/2011
• Est. Priority Date: 05/24/2010
• Status: Active Grant

• Current Assignee: Hardware & Software Technology Company Limited, Lenovo International Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Pham, Nam H., Mutnury, Bhyrav M., Rodrigues, Terence
• Granted Patent: US 8,901,946 B2
• Time in Patent Office: Days
• US Class Current: 324/756.04
• CPC Class Codes: G01R 31/2813 Checking the presence, location, orientation or value, e.g. resistance, of components or conductors orientation of the DUT with respect to the test fixture G01R1/06705, G01R31/281
• CPC Class Codes: G01R 31/2815 Functional tests, e.g. boundary scans, using the normal I/O contacts contacting devices G01R31/2808; testing digital circuits G01R31/317, G06F11/00

Abstract

Apparatus and methods for identifying a signal on a printed circuit board (‘PCB’) under test, including an integrated circuit mounted on the PCB, the integrated circuit having a test signal generator that transmits a test signal to an output pin of the integrated circuit, with the output pin connected to a test point on the PCB; the integrated circuit also having signal identification logic that inserts into the test signal, an identifier of the signal; a test probe in contact with the test point; and a signal-identifying controller that receives the test signal and the identifier from the test probe and displays, in dependence upon the identifier, the identity of the signal.

Claims

1. A method of identifying a signal on a printed circuit board (‘

PCB’

) under test, the method comprising;

transmitting a test signal from a test signal generator of an integrated circuit mounted on the PCB to an output pin of the integrated circuit, the output pin connected to a test point on the PCB;

inserting, by signal identification logic of the integrated circuit into the test signal, an identifier of the signal;

receiving, by a signal-identifying controller from a test probe in contact with the test point, the test signal and the identifier;

displaying, by the signal-identifying controller in dependence upon the identifier, the identity of the signal.

2. The method of claim 1 wherein the identity of the signal comprises one or more of:

a component name, a pin name, a schematic symbol name, and a signal name.

3. The method of claim 1 wherein inserting into the test signal an identifier of the signal further comprises inserting the identifier periodically at predetermined intervals.

4. The method of claim 1 wherein the identifier of the signal comprises the identity of the signal, and inserting an identifier of the signal further comprises:

demultiplexing the identifier to the output pin with a demultiplexer address; and

finding, in dependence upon the demultiplexer address in a list of signal identities, the identity of the signal.

5. The method of claim 1 wherein:

the identifier of the signal comprises the identity of the signal; and

displaying the identity of the signal further comprises extracting the identity of the signal from the test signal.

6. The method of claim 1 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal;

inserting an identifier of the signal further comprises demultiplexing the identifier to the output pin with a demultiplexer address; and

the method further comprises taking, by the signal identification logic as the encoded value, the demultiplexer address.

7. The method of claim 1 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal; and

displaying the identity of the signal further comprises extracting the encoded value from the test signal and decoding the encoded value.

8. The method of claim 1 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal; and

displaying the identity of the signal further comprises extracting the encoded value from the test signal and decoding the encoded value, including finding, in dependence upon the encoded value in a list of signal identities, the identity of the signal.

9. The method of claim 1 wherein:

the method further comprises configuring the integrated circuit with an initial demultiplexer address and a demultiplexer address range; and

inserting an identifier of the signal further comprises demultiplexing the identifier to the output pin with a demultiplexer address that satisfies I<

=A <

=(I+R−

1), where I is the initial demultiplexer address, A is the demultiplexer address, and R is the demultiplexer address range.

10. Apparatus for identifying a signal on a printed circuit board (‘

PCB’

) under test, the apparatus comprising;

a PCB under test, including an integrated circuit mounted on the PCB, the integrated circuit comprising a test signal generator that functions by transmitting a test signal to an output pin of the integrated circuit, the output pin connected to a test point on the PCB;

the integrated circuit further comprising signal identification logic that functions by inserting into the test signal, an identifier of the signal;

a test probe in contact with the test point; and

a signal-identifying controller that functions by receiving from the test probe the test signal and the identifier and displaying, in dependence upon the identifier, the identity of the signal.

11. The apparatus of claim 10 wherein the identifier of the signal comprises the identity of the signal, and inserting an identifier of the signal further comprises:

demultiplexing the identifier to the output pin with a demultiplexer address; and

finding, in dependence upon the demultiplexer address in a list of signal identities, the identity of the signal.

12. The apparatus of claim 10 wherein:

the identifier of the signal comprises the identity of the signal; and

displaying the identity of the signal further comprises extracting the identity of the signal from the test signal.

13. The apparatus of claim 10 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal;

inserting an identifier of the signal further comprises demultiplexing the identifier to the output pin with a demultiplexer address; and

the method further comprises taking, by the signal identification logic as the encoded value, the demultiplexer address.

14. The apparatus of claim 10 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal; and

displaying the identity of the signal further comprises extracting the encoded value from the test signal and decoding the encoded value.

15. The apparatus of claim 10 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal; and

displaying the identity of the signal further comprises extracting the encoded value from the test signal and decoding the encoded value, including finding, in dependence upon the encoded value in a list of signal identities, the identity of the signal.

16. A computer program product for identifying a signal on a printed circuit board (‘

PCB’

) under test, the computer program product disposed upon a computer readable storage medium, the computer program product comprising computer program instructions capable, when executed, of causing automated signal-identifying apparatus to function by;

transmitting a test signal from a test signal generator of an integrated circuit mounted on the PCB to an output pin of the integrated circuit, the output pin connected to a test point on the PCB;

inserting, by signal identification logic of the integrated circuit into the test signal, an identifier of the signal;

receiving, by a signal-identifying controller from a test probe in contact with the test point, the test signal and the identifier;

displaying, by the signal-identifying controller in dependence upon the identifier, the identity of the signal.

17. The computer program product of claim 16 wherein the identifier of the signal comprises the identity of the signal, and inserting an identifier of the signal further comprises:

demultiplexing the identifier to the output pin with a demultiplexer address; and

finding, in dependence upon the demultiplexer address in a list of signal identities, the identity of the signal.

18. The computer program product of claim 16 wherein:

the identifier of the signal comprises the identity of the signal; and

displaying the identity of the signal further comprises extracting the identity of the signal from the test signal.

19. The computer program product of claim 16 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal;

inserting an identifier of the signal further comprises demultiplexing the identifier to the output pin with a demultiplexer address; and

the method further comprises taking, by the signal identification logic as the encoded value, the demultiplexer address.

20. The computer program product of claim 16 wherein:

the identifier of the signal comprises only an encoded value that represents the identity of the signal; and

displaying the identity of the signal further comprises extracting the encoded value from the test signal and decoding the encoded value.