BOUNDARY-SCAN CIRCUIT USED FOR ANALOG AN DDIGITAL TESTING OF AN INTEGRATED CIRCUIT

• US 20050242980A1
• Filed: 04/30/2004
• Published: 11/03/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Schultz, David P., Jacobson, Neil G., McGettigan, Edward S., Collins, Anthony J., Fross, Bradley K.
• Granted Patent: US 7,102,555 B2
• Time in Patent Office: Days
• US Class Current: 341/155
• CPC Class Codes: G01R 31/3167 Testing of combined analog and digital circuits testing ADC's H03M1/1071
• CPC Class Codes: G01R 31/318555 Control logic
• CPC Class Codes: G11C 2029/0409 Online test
• CPC Class Codes: G11C 29/021 in voltage or current generators

Abstract

Method and apparatus are described for providing analog capability with boundary-scanning for an integrated circuit. The integrated circuit includes a boundary-scan controller (1517) coupled to an analog-to-digital converter (200). An analog channel is selected for input to the analog-to-digital converter (200). Analog information is converted to digital information by the analog-to-digital converter (200), and then such digital information may be stored in data registers (209) for reading out via the boundary-scan controller (1517).

Claims

1. An analog interface in an integrated circuit, comprising:

an analog-to-digital converter having a differential input;

a boundary-scan controller coupled to the analog-to-digital converter;

control logic coupling the analog-to-digital converter and the boundary-scan controller;

a multiplexer having an input side coupled to a plurality of analog channels and an output side coupled to the differential input of the analog-to-digital converter;

data registers coupled to outputs of the analog-to-digital converter;

the boundary-scan control configured to receive test information;

the control logic configured to provide a channel select signal as a control signal responsive to the test information;

the multiplexer coupled to receive the control signal to select a channel of the plurality of analog channels for outputting a differential analog output from the multiplexer and to the analog-to-digital converter; and

the analog-to-digital converter configured to convert the differential analog output into digital information for storing in a register of the data registers.

2. The analog interface, according to claim 1, wherein the integrated circuit is a programmable logic device having configurable logic.

3. The analog interface, according to claim 2, wherein the programmable logic device is a field programmable gate array.

4. The analog interface, according to claim 1, wherein the control logic is implemented in non-configurable logic.

5. The analog interface, according to claim 4, wherein the multiplexer is implemented in the non-configurable logic.

6. The analog interface, according to claim 1, wherein at least a portion of the plurality of channels are implemented using programmable inputs of the integrated circuit.

7. The analog interface, according to claim 6, wherein the control logic is configured to provide configuration information to the analog-to-digital converter to provide settings for the analog-to-digital converter.

8. The analog interface, according to claim 7, wherein the configuration information is obtained via the boundary-scan controller.

9. The analog interface, according to claim 8, wherein the boundary-scan controller is a Joint Task Action Group controller.

10. The analog interface, according to claim 1, wherein the analog-to-digital converter is a portion of a system monitor embedded in the integrated circuit.

11. The analog interface, according to claim 1, wherein the control logic comprises an address counter and a shift register for outputting via the boundary-scan controller the digital information stored in the register of the data registers.

12. The analog interface, according to claim 1, further comprising:

a digital-to-analog converter coupled to the control logic, the digital-to-analog converter configured to provide an analog signal from a digital input; and

a demultiplexer coupled to the plurality of analog channels and the digital-to-analog converter.

13. The analog interface, according to claim 12, wherein the digital-to-analog converter is configured to receive the digital input from the control logic responsive to the test information.

14. The analog interface, according to claim 13, wherein the analog signal is provided via the channel selected to a circuit under test.

15. The analog interface, according to claim 14, wherein the circuit under test is a mixed signal circuit.

16. The analog interface, according to claim 14, wherein the circuit under test is an analog sensor.

17. The analog interface, according to claim 16, wherein the analog sensor is external to the integrated circuit.

18. The analog interface, according to claim 16, wherein the analog sensor is internal to the integrated circuit.

19. The analog interface, according to claim 14, wherein the analog signal is to the circuit under test as a stimulus to cause a sensor output to be provided via the channel selected to the multiplexer for receipt by the analog-to-digital converter for conversion into the digital information for storage in the register.

20. A method for a mixed signal tester on an integrated circuit, comprising:

providing a system monitor having a digital bus and an analog-to-digital converter;

providing an analog interface coupled to the analog-to-digital converter via a multiplexer tree, the analog interface including a plurality of analog channels;

providing a boundary-scan controller coupled to the analog-to-digital controller via control logic, the boundary-scan controller being a digital interface;

providing at least one register coupled to the analog-to-digital converter for storing digital information;

sending test information in digital form via the boundary-scan controller to the integrated circuit for testing, the test information including digital testing information and analog testing information, the control logic coupled to receive the analog testing information for the analog-to-digital converter and the multiplexer tree;

selecting a channel of the plurality of analog channels responsive to the analog test information, the channel selected responsive to a control signal applied to the multiplexer tree;

obtaining an analog signal from the channel selected; and

converting the analog signal to digital test data with the analog-to-digital converter.

21. The method, according to claim 20, further comprising storing the digital test data in a register.

22. The method, according to claim 20, further comprising outputting the digital test data via the boundary-scan controller.

23. The method, according to claim 20, further comprising configuring configurable logic of the integrated circuit to provide at least a portion of the mixed signal tester.

24. The method, according to claim 23, wherein the integrated circuit is a programmable logic device.

25. The method, according to claim 24, wherein the programmable logic device is a field programmable gate array.