Re: Problem configuring Cyclone

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Matt,
Generally speaking, this kind of problem indicates that the device did
not correctly receive the preamble to the configuration bitstream, and
therefore did not start to process the data. This explains why nSTATUS
doesn't go low; the device has not yet started to look at the CRC for
each frame of data.

The #1 reason for configuration issues is signal integrity issues on
the DCLK signal. Even though it is running pretty slow, it's still a
clock and therefore sensitive to ringing. The ringing causes
double-clocking on the FPGA, so it sees a given bit twice. To diagnose
this, probe at the DCLK on the Cyclone device as close as you can and
observe the signal. If probing it makes it work, then it's signal
integrity as the capacitance of the probe is damping the ringing. Or
maybe you'll see ringing. Putting in a series termination at the
microprocessor, or a parallel termination at the Cyclone, will
generally solve this problem.

Other things to check:
- signal integrity on the DATA signal. Usually not a problem, but
possible.
- When you send the data to the Cyclone, make sure you send each byte
LSB first.

One of these is most likely the problem.

Sincerely,
Greg Steinke
snipped-for-privacy@altera.com
Altera Corporation


snipped-for-privacy@ettus.com (Matt Ettus) wrote in message
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Re: Problem configuring Cyclone
snipped-for-privacy@altera.com (Greg Steinke) wrote in message
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The problem turned out to be in the file I was sending.  I was using
an SOF, because I thought it was raw.  Once I found the .rbf option, I
switched to that, and it works now.  I didn't find mention of this in
appnote 250, which is on Cyclone configuration.

Thanks for your help.
Matt

Re: Problem configuring Cyclone
Matt,
Glad to hear that your configuration is working.
Thanks for the feedback on App Note 250. We have since replaced this
App Note with a chapter in the Cyclone Handbook. The link follows:
http://www.altera.com/literature/hb/cyc/cyc_c51013.pdf

We have updated the file type descriptions in this new chapter.
There's a section called "Device Configuration Files" which describes
the file types.

Sincerely,
Greg Steinke
snipped-for-privacy@altera.com
Altera Corporation



snipped-for-privacy@ettus.com (Matt Ettus) wrote in message
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