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CPLD-SPI_flash configuration system problem.

I have a problem width my CPLD-SPI_flash configuration system.

I have made a configuration interface for my Spartan 3 FPGA involving a CPLD (CoolRunner 2) and SPI flash (M25P32).

My FPGA is set up to serial master configuration mode. The FPGA is generating the clock for the CPLD and the CPLD transfers the data from the SPI flash to the DIN pin on the FPGA. I use the application notes and source code xapp800 from Xilinx.

I monitor the CPLD and it steps through states (1-4):

1 STATE_RESET 2 LOAD_READ_OPCODE 3 LOAD_READ_ADDRESS 4 READ_DATA 5 WAIT_STATE

The CPLD stays in state 4 where it waits for the FPGA to indicate configuration done by pulling the DONE pin high.

The hardware seams to work. I can see the data on the DIN pin of the FPGA but the FPGA never indicates configuration done by pulling the DONE pin high.

I think the problem may be the process of converting the .bit file to a format that can be written to the serial flash.

Anyone that have any suggestions on how to find the problem?

Andreas Beier Computer Systems Engineer

Reply to
mughat
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The first thing I always check is the bit order within bytes. Make sure the SPI isn't swapping your bits, or try swapping bits when you create the SPI flash image.

Reply to
Gabor

Do you use any special software tools for reading the .bit file and flash image?

Reply to
mughat

I don't usually use the .bit file directly. I use Impact to generate a PROM file in HEX format (or use promgen if you prefer a command line interface). This is a very simple format with just the bitstream and no header. Then I use a simple C program to turn this back into binary for storage in flash.

Impact or promgen gives you the choice of swapped or not swapped bits when generating the .hex file. Then if your embedded firmware gets the bit order wrong, you can just re-build the .hex file using the opposite swap mode rather than changing the firmware.

A note of warn> Do you use any special software tools for reading the .bit file and flash

Reply to
Gabor

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