Problems loading programs to BS2P40, USB 1.1 to blame?

Chuck E.

Hello All,

I am programming my BS2P40 through the Professional Development Board and a USB cable. On shorter programs to test individual functions, every once in a while I get an error message:

"Hardware Communication Failure! Check serial cable and power supply."

Both check out fine, so I was just putting up with this issue. But on one of my larger programs (memory map shows addressed from 210-7F0) I will get this message every time from a random spot between 12% loaded to about 85%. I reloaded the USB driver but still no help. Could it be that the older computer I'm stuck using with USB 1.1 (and running WinBlows 2k) is the problem? I will be moving the project to the neighboring desk to run off my desktop for a test to see, just wanted to know if anyone else had a similar problem.

Chuck

Mike Green

There's nothing obvious about the drivers vs. USB 1.1 that would explain this. What USB cable are you using? How about trying a different USB to serial adapter or a different USB cable. Both of those could introduce noise into the circuit that could explain this.

There are some settings affecting latency (how long it takes a packet of data to be forwarded through the USB adapter) that sometimes show up under WIN2K and other Windows OSs that might affect this.· I haven't experienced this, but I've heard of it.
·

Chris Savage

Hello,

Have you tried our troubleshooting FAQ on our USB Driver download page?

http://www.parallax.com/dl/docs/prod/ftdi/USBDriverTroubleshooting-V1.0.pdf

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Chris Savage
Parallax Tech Support

Chuck E.

I tried using a couple of different cables to rule that out, exact same issue with each cable. The USB to serial is built into the PDB, I'm pretty sure it's working OK, my desk computer also runs W2K but has USB 2.0 hardware and uploads the larger programs to it with no problems. I will try changing the latency IAW the directions from the link Chris posted. If I can't get that to work I will try having a USB 2.0 card installed in the lab computer and see if that helps.

The nice thing to come out of this is that we used this to convince the boss to go with leased computers for the offices and the fairly new (at least compared to the antiquated P.O.S.'s we're using in the lab) desktop computers we are using now will become available for use in the lab.

Chuck

Post Edited (Chuck E.) : 7/18/2007 3:14:25 PM GMT

Chuck E.

OK, the latency timer fix worked. Thanks Mike for mentioning it and thanks to Chris for pointing to the instructions.

You guys ROCK!

Chuck