Interfacing to the SPI PCM on a Nexys-3 Board

Hi All,

I am a complete newbie to FPGA design and am working on the final project for one of my classes in which we get to design and implement a program of our choosing on the Nexys-3 Spartan 6 board.

I am trying to design a program that displays images onto a VGA monitor and allows a user to progress through a set of images with a button press on the Nexys-3 board, and to do so I must interface with one of the external memories on the board to retrieve the data from the .bit files of the images (Which I stored on the SPI Flash memory using the Adept interface) and convert the data so it can be displayed on the monitor. The problem is I have never had to interface to an external memory for any of the other projects in my class and I have no idea where to start. I have spent over 10 hours researching the topic online and am still as lost as I was to begin with. The reference manual of the Nexys-3 points me to look at reference designs on the Digilent website, but there are none specific to the Nexys-3 board, and the Xilinx forms have proven to be no help either.

I understand the basics of what I need to get this project done (a basic understanding of SPI, debouncing, outputting to VGA, etc.), but I'm really struggling with interfacing with the SPI Flash Memory.

I was hoping someone might be able to point me in the right direction to understand how to do something like this, and any Verilog reference designs or code would be a massive help. I have attached both the reference manual for the Nexys-3 and the Data Sheet for the SPI Flash Memory.

Thank you in advance.

Sincerely,

A struggling student

I suppose you could use this for inspiration:
https://www.xilinx.com/support/documentation/application_notes/xapp1020.pdf
I haven't seen anything specific to Spartan 6.

The only thing that might not allow this to work is the fact that this device isn't a SPI flash but is a SPI PCM device. As the protocol is different (has no erase cycles) I'm not sure the method described for the Spartan 5 will be applicable. Xilinx actually uses the method described in xapp1020 to program the SPI flash devices on their own boards via the USB platform cable. When you want to use the Xilinx USB cable to program a SPI configuration flash the software initially programs a JTAG to SPI configuration image to the FPGA to allow configuration flash access from the JTAG port using a STARTUP primitive.

Regards