Intractable problems with boot PROM verify

Pluto/-II/-3/-P boards

Intractable problems with boot PROM verify

Postby bvarley » Sun Jan 01, 2012 2:57 am

Hi, Firstly, I've done all the obvious things:

Using a MAX232 for Pluto -> PC data line.
Serial I/O program on the FPGA board works fine.
RS232 levels and rise times on computer RxD are fine on a scope.
COM port on the machine concerned used constantly with other systems at 115K, without problems.

If I try to do a PROM burn on my laptop running XP it works fine.

With identical load file, cable, interface and FPGA Pluto-3 board on my desktop, running Win-7 I consistently get a verify error.
FPGAconf version is the same for both. Failurs occur with proven rbf files, such as LEDflasher.

The only difference I can see is XP vs Win-7. Has anyonre experienced anything similar? Any other suggestions? TIA
bvarley
 
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Re: Intractable problems with boot PROM verify

Postby fpga4fun » Sun Jan 01, 2012 7:42 am

So you have a WinXP laptop and Win7 desktop. It would be interesting to try Win7 on your laptop or WinXP on your desktop. I doubt the OS is the problem, most likely the machine.
fpga4fun
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Re: Intractable problems with boot PROM verify: SOLVED!

Postby bvarley » Sun Apr 27, 2014 6:30 am

Just for information, I've found the cause. If you're using the MAX232 version of the interface adaptor with a 5 volt supply, you need to bypass the regulator on the board (documentation doesn't cover). If you don't, the regulator chip will only output about 3 volts, not enough for the charge pumps on the MAX232.

There are a pair of 0.1" jumper lands immediately adjacent to the power connector. Just if you do add a bypass, take care not to inadvertently connect a higher voltage supply.
bvarley
 
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