Bad connectivity problems with parallel cable and CW

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Bad connectivity problems with parallel cable and CW

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eliben
Contributor I
Hello,
 
I use CW version 8 for 5683xx processors, and I have the 568367 evaluation board, with the parallel cable that came in the box.
 
I'm having lots of connection troubles with the parallel port, with "CCS" reporting various errors quite often. Sometimes it "fails to erase flash", other times "cable is not connected". Yet others is "core is not responding", but most of all "failed to verify flash".
 
With good luck, this happens only once in 5-6 times I hit "run" to download code. With bad luck, I'm becoming white with rage while failing to connect for an hour. With larger ELF files the problem is more severe.
 
Is there a solution for this punishment ? I realize the parallel port isn't the most robust way to do this, but this must work at least to some level when you purchase an evaluation board !!
 
Please help !
 
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J2MEJediMaster
Specialist I
The problem with the parallel port is that voltage levels of the signal lines can be on the edge of what's required to properly drive the interface. This causes the intermittant problems that you see. I've had a laptop that would work fine... if I didn't have any other peripheral, such as an external video, connected. As I had to use this laptop to do demos with an overhead projector, it was literally a show-stopper. Either switch to another system, or unplug all of the other peripherals to relieve the load on the power supply. Some computers are better at maintaining the voltage levels on the parallel port than others.

---Tom
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eliben
Contributor I
If this is a common and known problem, why does Freescale keep selling the parallel port solution as an operational one. I'm having problems with the 568xxx evaluation board and its connection cable - out of the box, why should such a thing happen ?
 
Isn't there any workaround for this, othen than buying a USB wiggler ?
Are there similar problems with the USB wiggler ?
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J2MEJediMaster
Specialist I
I won't say it's a common problem. It's just something that I happened upon because as a former trainer, I went through a lot of gear. Some laptops have rock-solid power supplies, and others seem to be on the edge. And again, the problem surfaced only when I was using my laptop to drive other peripherals besides the parallel port. If I didn't have to do a presentation, the parallel port wiggler worked just fine, and it took a lot of sleuthing for me to track the problem down. As for the paralell interface's voltage regulation, that's whatever the computer manufacturer does to build their box, which is out of our control. The only workaround that I know of is what I stated previously: either get a different box (not an option, probably) or disconnect as many peripherals as you can.

I have yet to see intermittant problems with a USB interface. It either works or it doesn't.

---Tom

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eliben
Contributor I
After battling with the problem for some time - I managed to alleviate it considerably using a shorter cable.
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dynode
Contributor I
For a couple of years we were using a parallel JTAG cable which had 2 feet or so of ribbon cable. Not from Freescale, so this may or may not apply exactly. This cable mostly worked. But once the board was installed in our equipment it was not convenient, so we added another 4 feet of ribbon cable. This was less reliable, and we discovered that both of them were very susceptible to electrical noise. If someone turned on an electrical device anywhere in the room, the debug session would crash, even when both the computer and the test board were powered by batteries. For a while we had a bad lamp ballast, and I had to turn the lights out to work on our board. We also tried making a 6-foot shielded cable, which only worked with some boards and some laptops. It was becoming absurd, so we got the USB-Tap. After some initial driver problems, it seems to work well. I don't have to rush through the debugging, trying to finish the test before it crashes, and the USB cable can be comfortably long. Oh, and it works on my new laptop with no parallel port!
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