Technique to test an integrated circuit using fewer pins

• US 6,538,469 B1
• Filed: 07/31/2000
• Issued: 03/25/2003
• Est. Priority Date: 06/10/1997
• Status: Expired due to Term

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Altera Corporation (Intel Corporation)
• Inventors: Sung, Chiakang, Huang, Joseph, Wang, Xiaobao, Nguyen, Khai, Wang, Bonnie
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Tan, Vibol
• Application Number:
  US09/630,071
• Time in Patent Office: 967 Days
• Field of Search: 326/38-41, 326/46, 326/47, 326/16, 365/201, 365/230.06, 714/724, 714/725, 714/744
• US Class Current: 326/40
• CPC Class Codes: G01R 31/318516 Test of programmable logic devices [PLDs]
• CPC Class Codes: G01R 31/318555 Control logic
• CPC Class Codes: G06F 11/2273 Test methods
• CPC Class Codes: H03K 19/17744 for input/output signals
• CPC Class Codes: H03K 19/17764 for reliability

Abstract

A technique to implement functions requiring fewer pins of an integrated circuit to serially transfer data into the integrated circuit for multiple logic blocks. By reducing the required pins, this permits downbonding of the integrated circuit into a package with fewer pins. This technique may be used to implement test Functions in a programmable logic device. Test data may be serially input using a test pin (410) for two or more columns (320) of logic blocks. The test data is stored in an A resister (330), and may be later transferred into a B register (335).

Claims

1. A programmable logic circuit comprising:

an array of logic blocks arranged in rows and columns;

an interconnect structure comprising first conductors between columns of the logic blocks and second conductors between rows of the logic blocks;

a plurality of test pins to interface with signals external to the programmable circuit, wherein each of the test pins provides test data to at least two columns of logic blocks;

a first register for two columns of logic blocks, wherein test data is loaded into the first register via one test pin; and

a second register for two columns of logic blocks, wherein test data stored in the first register is loaded into the second register in parallel.

2. A programmable logic circuit comprising:

an array of logic blocks arranged in rows and columns;

an interconnect structure comprising first conductors between columns of the logic blocks and second conductors between rows of the logic blocks;

a plurality of test pins to interface with signals external to the programmable circuit, wherein each of the test pins provides test data to at least two columns of logic blocks;

a fist multiplexer coupled to selectively pass a first signal from a test pin or a second signal to a first multiplexer output;

a first flip-flop, coupled to the first multiplexer output;

a second flip-flop, coupled to a first flip-flop output; and

a second multiplexer, coupled to a second flip-flop output, a second multiplexer output coupled to a logic block.

3. The programmable logic circuit of claim 2 wherein the first flip-flop is further coupled to a first clock line and the second flip-flop is further coupled to a second clock line.

4. The programmable logic circuit of claim 2 wherein the second multiplexer is further coupled to a second flip-flop inverted output.

30. The programmable logic circuit of claim 2 wherein the first flip-flop is in a first register and the second flip-flop is in a second register.

5. A programmable logic circuit comprising:

a plurality of logic array blocks arranged in rows and columns;

an interconnect structure comprising a first plurality of conductors between columns of the logic array blocks and a second plurality of conductors between the rows of the logic array blocks;

a plurality of test pins;

a first plurality of registers, each selectively coupled to one of the plurality of test pins; and

a second plurality of registers, each coupled between one of the first plurality of registers and a column of logic array blocks.

6. The programmable logic circuit of claim 5 wherein each of the first plurality of registers comprises a first clock line, and test data is serially shifted from the plurality of test pins to the first plurality of registers under control of a first clock signal on the first clock line.

7. The programmable logic circuit of claim 6 wherein each of the second plurality of registers comprises a second clock line, and test data is transferred in parallel from the first plurality of registers to the second plurality of registers under control of a second clock signal on the second clock line.

8. The programmable logic circuit of claim 7 wherein each of the first plurality of registers comprises:

a plurality of flip-flops arranged in a serial chain, a first flip-flop in the serial chain selectively coupled to one of the plurality of test pins.

31. The programmable logic circuit of claim 5 wherein each of the second plurality of registers flier couple to another column of logic array blocks.

32. The programmable logic circuit of claim 8 wherein each of the second plurality of registers comprises:

a plurality of flip-flips, each flip-flop coupled to a FIFO chain in the column of logic array blocks.

9. A programmable logic circuit comprising:

a plurality of logic array blocks arranged in rows and columns;

an interconnect structure comprising a first plurality of conductors between columns of the logic array blocks and a second plurality of conductors between the rows of the logic array blocks;

a test pin;

a first register selectively coupled to the test pin; and

a second register coupled between the first register and at least two columns of logic array blocks.

10. The programmable logic device of claim 9 wherein the first register comprises a chain of flip-flops, each having an input, an output, and a clock input.

11. The programmable logic device of claim 10 wherein the clock input of each of the flip-flops in the first register couple to a first clock line, and test data is shifted from the test pin into the first register under control of a first clock signal on the first clock line.

12. The programmable logic device of claim 11 wherein the second register comprises a plurality of flip-flops, each having an input, an output, and a clock input, each input of a flip-flop in the second register couples to an output of a flip-flop in the first register, and each output of a flip-flop in the second register couples to a column of logic array blocks.

13. The programmable logic device of claim 12 wherein the clock input of each of the flip-flops in the second register couple to a second clock line, and test data is transferred in parallel from the first register to the second register under control of a second clock signal on the second clock line.

14. The programmable logic circuit of claim 13 wherein the first register comprises at least 32 flip-flops.

15. The programmable logic circuit of claim 9 wherein a first flip-flop in the first register is coupled to a second flip-flop in the first register and a first flip-flop in the second register.

16. The programmable logic circuit of claim 15 further comprising:

a multiplexer having a first input, a second input, and an output, wherein the first input is coupled to an output of the first flip-flop in the second register and the second input is coupled to an inverting output of the first flip-flop in the second register.

17. The programmable logic circuit of claim 15 further comprising:

a multiplexer having a first input, a second input, and an output, wherein the first input is coupled to the test pin and the output is coupled to the first flip-flop in the first register.

33. The programmable logic circuit of claim 9 wherein the second register is coupled to a plurality of FIFO chains in the columns of logic array blocks.

34. The programmable logic circuit of claim 15 wherein the first flip-flop in the second register is coupled to a FIFO in one of the columns of logic array blocks.

18. A programmable logic circuit comprising:

a plurality of logic array blocks arranged in rows and columns;

an interconnect structure comprising a first plurality of conductors between columns of the logic array blocks and a second plurality of conductors between the rows of the logic array blocks;

a test pin;

a first flip-flop having an input coupled to the test pin, a clock input, and an output;

a second flip-flop having an input coupled to the output of the first flip-flop, a clock input, and an output;

a third flip-flop having an input coupled to the output of the first flip-flop, a clock input, and an output coupled to a column of logic array blocks; and

a fourth flip-flop having an input coupled to the output of the second flip-flop, a clock input, and an output coupled to the column of logic array blocks.

19. The programmable logic circuit of claim 18 wherein the clock input of the first register and the clock input of the second register couple to a first clock line.

20. The programmable logic circuit of claim 19 wherein the clock input of the third register and the clock input of the fourth register couple to a second clock line.

21. A programmable logic circuit comprising:

a plurality of logic array blocks arranged in rows and columns;

an interconnect structure comprising a first plurality of conductors between columns of the logic array blocks and a second plurality of conductors between the rows of the logic array blocks;

a test pin;

a shift register having an input coupled to the test pin; and

a parallel register having inputs coupled to outputs of the shift register, and outputs coupled to at least one column of logic array blocks.

22. The programmable logic circuit of claim 21 wherein the shift register comprises a chain of flip-flops, and a first flip-flop in the chain is coupled to the test pin.

23. The programmable logic circuit of claim 22 wherein the parallel register comprises a plurality of flip-flops, each having an input coupled to an output of a flip-flop in the first register, and an output coupled to a column of logic array blocks.

25. The integrated circuit of claim 21 wherein each of the test pins receives test data to at least two columns of logic blocks.

26. The integrated circuit of claim 21 wherein the second register is coupled to a plurality of First-In First-Out (FIFO) chains.

27. The integrate circuit of claim 21 wherein test data is loaded into the first register under control of a first clock signal on a first clock line, and data is transferred in parallel to the second register under control of a second clock signal on a second clock line.

35. The programmable logic circuit of claim 21 wherein the parallel register is firer coupled to a plurality of FIFOs in a column of logic array blocks.

24. An integrated circuit comprising:

an array of logic blocks arranged in rows and columns;

a plurality of test pins, wherein each of the test pins receives test data for at least one column of logic blocks;

a fist register, wherein test data is loaded into the first register serially via a test pin; and

a second register, wherein test data stored in the first register is loaded into the second register in parallel.

28. An integrated circuit comprising:

an array of logic blocks arranged in rows and columns;

an interconnect structure comprising fist conductors between columns of the logic blocks and second conductors between rows of the logic blocks;

a plurality of test pins, wherein each of the test pills receives test data for a plurality of columns of logic blocks;

a first register comprising a series of flop-flops, a first flip-flop selectively coupled one of the plurality of test pins, wherein test data is loaded into the first register serially via a test pin under control of a first clock signal on a first clock line; and

a second register comprising a plurality of flip-flops, each of the plurality of flip-flops coupled to one of the series of flip-flops in the first register, the second register coupled to a plurality of columns of logic blocks, wherein test data stored in the first register is loaded into the second register in parallel under control of a second clock signal on a second clock line.

29. The integrated circuit of claim 28 wherein each of the plurality of flip-flops in the second register is coupled to a FIFO chain in the plurality of column of logic block.