I have a couple of questions about the board layout of the spartan3 and platform flash. In the spartan-3 family guide there is a schematic for programming the spartan-3 from a platform flash on page 33. To put the spartan 3 in master serial mode you need M0-M2 (mode pins) as 000. In theory the spartan-3 and platform flash should step through the flow chart of boot up mode.
Do I need to then change the mode pins, or is it okay to leave them hardwired to GND ?
My second question is about JTAG. In order to make this in-system programmable I would of course like to use my JTAG port just like on the sp-3 starter kit. Do I need to do anything in particular to the mode pins, M0-M2, at this point or does JTAG override them so that I can then program up the platform flash just like I do with the starter kit?
I had always thought the JTAG would be dominant (using IMPACT) but this isn't something I want to leave to chance, as prototype boards aren't cheap when you aren't doing them yourself.
Thanks very much for your time.