I'm trying to read counter0 on a U3. But I continually get an error code 7 back instead of the counter value. I left the timer clock at the default, so that shouldn't be stopping counter0 from working (I also tried setting the timer mode to 2). I need to be able to use both counters. I'm confused.
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I have made a discovery. The "power" routine (used extensively in u3.c) doesn't work when compiled with gcc. Gosh knows what it does, but it's definitely WRONG. I changed that (just made it a left shift, because it's only called to do power of 2), and I think things may now be better.
For clarification, what is the "power" routine you mention?
What functions from u3.h/c are you using that were not working before your modification? eTCConfig and eTCValues? What configuration are you using with them?
This is right out of the top of u3.c. Obviously I added the "error handling," but the commented out line is what was there originally.// modified to only powers of 2 - didn't work
int power (int iItem, int iPower) {
if (iItem != 2) {
printf ("power of %d doesn't work\n", iItem);
}
return (0x01 << iPower);
// return (iItem ^ iPower);
}
Yes, eTCConfig, and eTCValues were how I found the problem. But there are lots of other routines in u3.c that use power, and I didn't test any of the others. Where I specifically saw it was:
if( i + TCPinOffset < 8 )
FIOAnalog = FIOAnalog - power(2, i + TCPinOffset);
else
EIOAnalog = EIOAnalog - power(2, (i + TCPinOffset - 8));
Where FIOAnalog (and I presume EIOAnalog) was getting seriously screwed up.
Does that help?
There is also a minor bug in eTCConfig:
// if( TCPinOffset < 0 && TCPinOffset > 8 ) RGB
if( TCPinOffset < 0 || TCPinOffset > 8 )
The commented out line is unlikely ever to be true! But all it's doing is telling you there's an error.
Roger
Thanks for pointing out the code.
I checked the code calculating FIOAnalog and EIOAnalog with pow, and it functions as expected when compiled with GCC/G++. It is calculating which FIO and EIO lines need to be digital I/O (bit = 0) for the timer/counter lines.
if( TCPinOffset < 0 && TCPinOffset > 8 )
The above check you pointed out is a bug. I'll correct that soon as it should be using an "or" instead of "and".
As for error code 7, that can occur if you are trying to use a timer or counter with eTCValues, but it wasn't enabled/configured with eTCConfig.
You and I must have different u3.c versions. "My" routine is power, not pow. And I found the problem because ehfeedback wasn't returning as many bytes as I was expecting, because it was instead returning an error. When I tracked that down I got, eventually, to the problem. Whether that was resulting in the error code 7 I know not. I had a bunch of routines I was working on, and I think it was an eAIN call that had me find the problem.
The code that I am checking and refering to is from the u3.c from the Exodriver source on GitHub, which uses the pow function from math.h. I also checked the eAIN usage of pow and their calculations are correct.
Note with the Feedback command-response that if there is an error code in the response, the response size can be smaller than expected causing the "ehFeedback error : did not read all of the expected buffer" message. Only response data before the errored IOType is returned, as documented here for the ErrorFrame byte:
https://labjack.com/support/datasheets/u3/low-level-function-reference/f...
Thanks for all the work you're putting ing! My u3.c was from an exodrive-master.zip, which I downloaded from somewhere on 7/26/18. And yes, it was the ehFeedback error message that (finally) led me to figure out what the heck was going on. Anyway, all is good now. :-)