Hi, This is pretty old news but... During FPGA programming we have found it necessary to fist clear the IC's configuration memory before writing the new design. We do this by selecting the "Pulse PROG" option in the programming dialog box.
We have also found that sometimes that we have to slow down the TCK speed over the programming cable. This is often a function of the programming computer in use. Something seems strange about current surging on a running board. I have not seen this. I have seen the current be 7 to 8 amps on iBob + 2 iADC when the iADC input clock isn't correctly supplied. But then the iBob really isn't running correctly. Matt Dexter On Mon, 11 Aug 2008, Dan Werthimer wrote: > > > > hi alan, > > are you referring to the large current jump that occurs > just after downloading the FGPA? i think an unprogrammed > ibob pulls about 1 amp, and a fully programmed ibob running at > 200 MHz pulls about 6 amps. > > best wishes, > > dan > > > > Henry Chen wrote: > > Hi Alan, > > > > Sorry for taking a while to respond. In the future I highly recommend that > > you email all questions to [email protected]. This will not only > > help you access a wider pool of resources, but also helps everybody else in > > case they run into the same problem down the line. > > > > I don't think I've ever heard of the current consumption spiking by several > > amps. What kind of timescale does that occur on? > > > > As far as the FPGA power-on global reset goes, I don't know of a way to > > hold > > it off, but there may be a bitgen parameter. Are you getting switching > > noise > > as you're programming the FPGA? > > > > Thanks, > > Henry > > > > Alan Hinton wrote: > >> Hi Henry, > >> > >> Hope all is well. Hopefully a quick question. We have noticed that > >> once in awhile the iBOB FPGA does not get loaded correctly. I believe > >> that we have narrowed it down to the power supply voltage dipping as > >> the supply voltage rises which causes the FPGA load to be disrupted. > >> While tracking this down I have noticed that there are current surges > >> as the board is running (several amps). Have you noticed or heard > >> anything like this? Also is there a way to hold off the reset signal > >> (delay it longer)? > >> > >> Thanks > >> > >> Alan > >> > >> Haystack > >> > > > >
