Supporting multiple FPGA configuration modes using dedicated on-chip processor

• US 6,496,971 B1
• Filed: 02/07/2000
• Issued: 12/17/2002
• Est. Priority Date: 02/07/2000
• Status: Expired due to Term

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Trimberger, Stephen M., Lesea, Austin H.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Kik, Phallaka
• Application Number:
  US09/499,499
• Time in Patent Office: 1,044 Days
• Field of Search: 716/1-21, 713/1-100, 710/8-14, 711/1-6, 326/37-50
• US Class Current: 716/128
• CPC Class Codes: G06F 30/34 for reconfigurable circuits, e.g. field programmable gate arrays [FPGA] or programmable logic devices [PLD]

Abstract

An FPGA has an on-chip processor that reads configuration data onto the FPGA and controls the loading of that configuration data into FPGA configuration memory cells. After FPGA power-up, the processor reads a configuration mode code from predetermined terminals of the FPGA. If the configuration mode code has a first value, then the processor executes a first configuration program so that configuration data is received onto the FPGA in accordance with a first configuration mode. If the configuration mode code has a second value, then the processor executes a second configuration program so that configuration data is received onto the FPGA in accordance with a second configuration mode. The configuration programs can be stored in metal-mask ROM on-chip so they can be changed without re-laying out the remainder of the FPGA. Providing multiple configuration programs allows the FPGA to support multiple configuration modes using the same processor hardware. One configuration mode code causes the processor to execute a loader program that in turn loads a configuration program onto the FPGA from a source external to the FPGA. Once the configuration program is loaded, the processor executes the configuration program thereby allowing the FPGA to support a custom configuration mode.

Claims

1. A method of configuring a programmable logic structure of a programmable integrated circuit, the programmable integrated circuit comprising the programmable logic structure, a plurality of terminals, a processor and a plurality of configuration programs, the method comprising:

(a) reading by the processor one of a plurality of configuration mode codes from the plurality of terminals, the configuration mode code indicating one of the plurality of configuration programs; and

(b) executing on the processor said one of the plurality of configuration programs determined by the configuration mode code read by the processor, execution of said one of the plurality of configuration programs causing configuration data to be read onto the programmable integrated circuit and to configure the programmable logic structure.

2. The method of claim 1, wherein the processor executes a first of the configuration programs if the configuration mode code read in (a) has a first value, and wherein the processor executes a second of the configuration programs if the configuration mode code read in (a) has a second value.

3. The method of claim 1, wherein said one of the plurality of configuration programs and the processor together are a means for causing configuration data in a first format to be read onto the programmable integrated circuit, and wherein another of the plurality of configuration programs and the processor together are a means for causing configuration data in a second format to be read onto the programmable integrated circuit.

4. The method of claim 1, wherein said one of the plurality of configuration programs and the processor together are a means for causing configuration data to be read onto the programmable integrated circuit in a serial fashion via a single terminal of the programmable integrated circuit, and wherein another of the plurality of configuration programs and the processor together are a means for causing configuration data to be read onto the programmable integrated circuit in a parallel fashion via a plurality of terminals of the programmable integrated circuit.

5. The method of claim 1, wherein said one of the plurality of configuration programs and the processor together are a means for causing configuration data to be read onto the programmable integrated circuit in a serial fashion via a single terminal of the programmable integrated circuit and converted to a parallel data stream for applying to configuration memory cells.

6. The method of claim 5, wherein said one of the plurality of configuration programs and the processor together cause configuration data to be applied to a serial-in terminal of a shift register and to be read out on parallel output terminals of the shift register.

7. The method of claim 1, wherein the plurality of configuration programs is stored in a metal-mask readonly-memory (ROM) on the programmable integrated circuit.

8. The method of claim 1, wherein during execution of said one of the plurality of configuration programs the processor controls whether a terminal of the programmable integrated circuit is configured as an input terminal or as an output terminal.

9. The method of claim 1, wherein said reading of the configuration mode code by the processor occurs automatically after power-up of the programmable integrated circuit.

10. The method of claim 1, wherein the programmable integrated circuit is a field programmable gate array (FPGA), the configuration data being loaded into memory cells in the FPGA thereby configuring the FPGA.

11. The method of claim 1, wherein the programmable logic comprises a programmable interconnect structure.

12. A method of configuring a programmable integrated circuit, the programmable integrated circuit comprising a programmable logic structure, a processor, and a memory containing a first program and a second program, the method comprising:

receiving a configuration mode code onto the programmable integrated circuit;

if the configuration mode code has a first value then executing on the processor the first program and thereby reading first configuration data in a first format onto the programmable integrated circuit;

if the configuration mode code has the first value then configuring the programmable logic structure using the first configuration data;

if the configuration mode code has a second value then executing on the processor the second program and thereby reading second configuration data in a second format onto the programmable integrated circuit; and

if the configuration mode code has the second value then configuring the programmable logic structure using the second configuration data.

13. A programmable integrated circuit, comprising:

a programmable logic structure;

at least one code terminal;

a memory storing a first configuration program and a second configuration program; and

a processor, wherein the processor reads the at least one code terminal and determines, based on a configuration mode code on said code terminal, whether to execute the first configuration program or to execute the second configuration program, wherein execution of the first configuration program would cause first configuration data to be read onto the programmable integrated circuit and to configure the programmable logic structure, and wherein execution of the second configuration program would cause second configuration data to be read onto the programmable integrated circuit and to configure the programmable logic structure.

14. The programmable integrated circuit of claim 13, wherein the configuration data read onto the programmable integrated circuit using the first configuration program would be received onto the programmable integrated circuit in serial fashion via a single terminal of the programmable integrated circuit, and wherein the configuration data read onto the programmable integrated circuit using the second configuration program would be received onto the programmable integrated circuit in parallel fashion via a plurality of terminals of the programmable integrated circuit.

15. A programmable integrated circuit, comprising:

a programmable logic structure;

a plurality of terminals;

a memory storing a first configuration program and a second configuration program; and

means for reading a configuration mode code from the plurality of terminals, and for executing the first configuration program if the configuration mode code has a first value, and for executing the second configuration program if the configuration mode code has a second value, wherein if the first configuration program is executed then configuration data in a first format is received onto the programmable integrated circuit and is used to configure the programmable logic structure, and wherein if the second configuration program is executed then configuration data in a second format is received onto the programmable integrated circuit and is used to configure the programmable logic structure.

16. The programmable integrated circuit of claim 15, wherein the means for reading comprises a processor.

17. The programmable integrated circuit of claim 15, wherein the first format is a serial format, and wherein the second format is a parallel format.

18. The programmable integrated circuit of claim 17, wherein the configuration data in the first format is converted to a parallel format before being input into a processor.

19. The programmable integrated circuit of claim 15, wherein the memory comprises a read-only-memory (ROM).

20. A method of configuring a programmable logic structure of a programmable integrated circuit, the programmable logic structure having configuration memory cells, the programmable integrated circuit comprising the programmable logic structure, a processor, and a plurality of terminals, the method comprising:

(a) reading by the processor a configuration mode code from the plurality of terminals, the configuration mode code having a first value;

(b) executing on the processor a loader program if the configuration mode code has the first value, wherein execution of the loader program causes the processor to read a configuration program onto the programmable integrated circuit; and

(c) executing on the processor the configuration program such that the processor reads configuration data onto the programmable integrated circuit and loads the configuration data into the configuration memory cells of the programmable logic structure.

21. The method of claim 20, wherein the configuration data is read onto the programmable integrated circuit in (b) as a plurality of N-bit words, the N-bit words being received onto the programmable integrated circuit one after another on the same terminals.

22. A programmable integrated circuit, comprising:

a programmable logic structure comprising a plurality of configuration memory cells;

a plurality of terminals;

a memory storing a loader program; and

a processor that reads a configuration mode code from the plurality of terminals and if the configuration mode code has a first value then the processor executes the loader program, wherein execution of the loader program causes the processor to read a configuration program onto the programmable integrated circuit and execute the configuration program, wherein execution of the configuration program causes configuration data to be read onto the programmable integrated circuit and to be loaded into the configuration memory cells of the programmable logic structure.

23. A programmable integrated circuit, comprising:

a programmable logic structure comprising a plurality of configuration memory cells;

a plurality of terminals;

a memory storing a loader program; and

means for reading a configuration mode code from the plurality of terminals and if the configuration mode code has a first value then the means executes the loader program, wherein execution of the loader program causes the means to read a configuration program onto the programmable integrated circuit and to execute the configuration program, wherein execution of the configuration program causes configuration data to be read onto the programmable integrated circuit and to be loaded into the plurality of configuration memory cells.

24. The programmable integrated circuit of claim 23, wherein the means for reading comprises a processor.

25. The programmable integrated circuit of claim 24, wherein the means for reading further comprises a frame buffer, wherein the configuration data are loaded into the frame buffer in serial fashion under the control of the processor, and the configuration data are then transferred from the frame buffer to the plurality of configuration memory cells in parallel fashion under control of the processor.

26. The programmable integrated circuit of claim 23, wherein the means for reading further comprises an X register and a Y register, wherein the processor controls the X register and the Y register such that selected ones of the configuration memory cells are accessed and loaded with the configuration data.

27. The programmable integrated circuit of claim 23, wherein the memory comprises both a read-only-memory (ROM) and a random-access-memory (RAM).

28. A programmable integrated circuit comprising:

a programmable logic structure;

a programmable interconnect structure;

a plurality of terminals;

a processor that automatically reads a configuration mode code from the plurality of terminals after power-up of the programmable integrated circuit; and

a configuration structure for configuring the programmable logic structure and the programmable interconnect structure, the configuration structure being controlled by the processor.

29. A method of controlling configuration of a programmable integrated circuit having a programmable logic structure, a programmable interconnect structure, and a configuration structure, the method comprising the steps of:

configuring the configuration structure;

reading a configuration mode code onto the programmable integrated circuit using the configuration structure;

reading configuration data onto the programmable integrated circuit and using the configuration data to configure the programmable logic structure and the programmable interconnect structure; and

reconfiguring the configuration structure.

30. The method of claim 29, wherein the configured programmable logic structure, the configured programmable interconnect structure, and the reconfigured configuration structure together realize a user-specific circuit.

31. The method of claim 30, wherein the configuration structure is controlled by a processor located on the programmable integrated circuit.

32. A programmable integrated circuit, comprising:

a programmable logic structure having a plurality of configuration memory cells;

a plurality of terminals;

a processor that automatically reads a configuration mode code from a source external to the programmable integrated circuit; and

a serial-to-parallel converter connected to at least one of said plurality of terminals and to said processor, wherein if the configuration mode code has a predetermined value then said serial-to-parallel converter converts configuration data from serial format to parallel format, the processor reading said configuration data in parallel format from said serial-to-parallel converter and causing said configuration data to configure said programmable logic structure.