serial configuration of Spartan 3 FPGA

I am currently developing a system where a user can configure an Spartan 3 FPGA from a Atmega 128(serial configuration). The system consists of FPGA, SRAM, Atmega128 and Dataflash. The system is connected as follows. Atmega128--->Dataflash, Atmega128--->FPGA, FPGA--->SRAM.

Now I have run into this problem.

As per my board layout the "DIN" signal of the Spartan 3 is connected to the SRAM where the conifiguration data is expected to be kept. The other serial configuration signals (INIT, PROG, CCLK, DONE) are available from the Atmega128.

How would I got about configuring the FPGA. The SRAM is not connected to the Atmega128.

My though process says that I need to have implemented an SRAM interface on the FPGA to access it, but then it is a catch-22 situation, as I need to configure the FPGA first. I do have a JTAG interface available to FPGA (which I implemented if such situations arose). But if I implement an SRAM interface on the FPGA (using JTAG), it will void the whole idea of configuring the FPGA from microcontroller.

Any ideas?

Can I configure the FPGA serially using either the D1, D2, D3 or D4 pins (which for some reason I connected to the Atmega 128)?

Yaju Nagaonkar

Electrical and Computer Engineering
Brigham Young University
 Click to see the full signature
Reply to
Yaju Nagaonkar
Loading thread data ...

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.