RobotC program error


Does anyone know what to do when encountering this error?

Was everything working before this error occurred? How are you downloading, through the joystick or using the USB A-A cable? Which version of ROBOTC?

Quit ROBOTC and reboot perhaps…

hi, we have had similar problems before with this, if you are using the usb a-a cable, unplug it and try it again …

also, if you are using the programming hardware kit (old type), check battery power and vexnet connection … if not this, check the communication settings (what method are you using) ?

We are using the old programming hardware kit. The batteries/vex net connection seem fine however when I select the communication port under “view” as it says in the error description, it says “automatic selection” and the communication port cannot be changed.

Try resetting your computer, and also make sure that the drivers are properly installed, especially if your using XP. I found the #1 error that I have when using RobotC is having the drivers not installing properly.

Make sure the prolific driver is loaded correctly in the device manager.

ROBOTC will generally find the correct com port automatically, you don’t normally need to select it under prefs/platform, however, it should show up in the list of available ports.

Could the problem possibly be that I am running Windows 8? Some of the options from your screenshot did not show up.:confused:

Absolutely. See this. That screen shot was from XP, just to give you an idea.

Hatuschka, after a bunch load of trial and error I have found that the old programming hardware just sucks with new technology, the new drivers will not work with the oldprogramming kit . I had to use drivers from 2011. You have to “update” the driver each time you plug in the programming kit and even then it might not work half the time. I am alsousing windows 8 and iit’s frustrating when the programming kit drivers don’t even work!

My recommendation is that if possible, buy one of the new programming cables or borrow one, they are almost hassle free (the odd driver issue here and there).

The prolific chip in the programming adapter is not supported by Windows 8 if you believe the prolific web site.

When I run the checkChipVersion tool under XP I get the following.


Now, this doesn’t mean it wont work but the PL2303 is at least 10 years old (although it’s been updated over the years) and like everything it is becoming obsolete.

I will try to find a new cable to borrow from one of the teams at my school, I the meantime is it possible to directly download the program from my laptop to the cortex over a USB-USB cable?

Sure, as long as the VEX driver is correctly loaded, just plug it in and try.

I have the old hardware kit working fine with windows 8, please see my post

note the bit about rolling back driver.

One other thing to check if you have the older kit is the “phone” cable. We had been having odd intermittent problems. I clipped off the ends and re-crimped with new ends and so far so good.

Caution: the cables are 6 wire cables and you need have to have the right 6 wire ends. Most RJ11 crimpers will also crimp 6 wire plugs but check yours first.

Also if you find a specific USB port on your system that works consistently, use it every time. differences in USB controller hardware could also play a part.


Besides all of the tips suggested above, please also consider the 3.55.2 BETA as it improves the COM port handling in ROBOTC and has solved the ‘Error 2(0x2): The system cannot find the file specified.’ issue for many users.

Please let us know if the beta works for you, and as always, we appreciate any and all feedback you are able to give on ROBOT, as the feedback we receive is what helps us improve ROBOTC.

John, is it possible to put the download for version 3.51 on your download site? I’d like to test 3.55.2 BETA but would like to be able to redownload vs 3.51 (not 3.54) if I have problems. All my laptops currently have 3.51. Thanks.

It’s available here

Thanks. Have you tried vs 3.55.2 yet? I was avoiding vs 3.54 because of the download problems others were having.

I have tried 3.55.2 ( as well as many other betas :slight_smile: ) and don’t remember any particular problems. My teams are still using 3.51 as that’s the version on the 75 PC’s in the computer lab. I discourage upgrades, unless there are features that are really necessary, so we have skipped 3.54 for now as it did not add to the competition code. CMU will release 3.XX soon (number TBD), this will have PID for speed control and perhaps driving to an encoder target. They continue to put significant time and effort into this software trying to add the features that we all want.