Need a bit of hand-holding for simple board design

Aug 13, 2008 3 Replies

Hey all....



...am putting together a simple board consisting of an FT232 (USB-



serial) + Spartan 3a + flash for serial programming....I have the

schemmys for the 3a board from Avnet, however, that board (and most eval boards I've seen) have more complex setups than I need and is difficult to discern which elements to rip out. Basically, I just want the simplest possible design since my processing will just be communicating with a PC via USB. So besides power, I believe all I need is the above, correct?


I could use some help, or example schemmys if you know of any, which are easier to copy from than the eval boards which are multiplexing multiple external flash/eeproms to program the fpga in multiple ways. I just want a simple serial download from a simple flash or eeprom. I think I can handle connecting up the FTDI chip to the fpga since that's application specific. I guess what I need specifically, is a simple schemmy on how to connect a programmer flash to a spartan 3a to program it on power-up...or any simpler solution you can think of...


please let me know of how I can be more specific...am just getting started with this and can use all the help I can get...


thanks a lot!

Spartan 3a + flash for serial programming....I have the

You need to program the Spartan somehow. This board uses the Cypress pSOC mixed signal array or whatever (everyone else calls it microcontroller). You can also config the Spartan with serial flash.

) + Spartan 3a + flash for serial programming....I have the

If you want dead simple, buy a Xilinx PROM and use it in "slave serial" mode. It's more expensive, but there's less room for error. Look at the PROM datasheet and the Configuration section of the FPGA datasheet.

What you probably also want are the schematics to an earlier Spartan-3 dev board, one that just uses platform flash and has a JTAG connection. Be aware though that pullup resistor values and such vary between 3 and 3A.

Spartan 3a + flash for serial programming....I have the

You still need to program the PROM somehow. It's simple for productions, but not for developments.

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