Product Category: All Family: Spartan 3E Device: XC3S500E Package: FG320 Speed: -4
I wasn't sure about the speedgrade - but I googled around and found some other people had used -4 for that option on similar boards. Is that the correct choice? How would I figure that out? Also, what exactly does the speedgrade mean? The help file wasn't very verbose about it.
Thanks!
-Michael
Hi Michael, It's written on the chip. You'll see 4C somewhere, I expect. This is speedgrade 4, commercial temperature range. The speedgrade is used to guarantee the speed of the innards of the device. Read the datasheet, and look for the 'switching characteristics' section. HTH., Syms.
Hi Symon - you're right - 4C is printed on the chip. Thanks for the help!
I've just run into one other problem: I tried changing my code around a bit - I changed one of the output names and added a new output. I then went to assign package pins and assigned pins to the two new outputs. I then tried to generate a programming file. This gave me an error about the .ucf containing a reference to the old name of the output whose name I changed. I couldn't figure out why that would happen though. When I did the "assign package pins" shouldn't it have fixed that? I mean - when I assign package pins doesn't that create the .UCF file? Eventually I clicked on "Edit Constraints (text)" and removed the line (which was the very first line, oddly enough, above where it says "#PACE: Start of Constraints generated by PACE") that referenced the old output name. That fixed the problem and I was able to generate the programming file and program it just fine. But what was the proper way to deal with that? I'm very new to all this so I want to make sure I don't get into any bad habits.
Thanks!
-Michael
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