Re: program not downloading
ROBOTC performs an integrity check on the battery level before writing files to the NXT as at marginal battery level the NXT CPU operates OK except when writing to flash, corruption can occur. The corruption can occur at any flash location and not simply the addresses that you're trying to write.
Clearly what's happening here is that the message to retrieve the battery value from the NXT is returning a garbage result. You won't get a ngeative battery level.
I suspect what's wrong here is that something has got out of sync. This could be: Firmware version mismatches, USB communications is corrupted, or something similar.
One or more of the following is likely to clear the problem:
- Power cycle the NXT
- Unjack and rejack the USB connection to the NXT.
- Exit and re-enter the ROBOTC application.
- Restart Windows and re-enter the ROBOTC application.
- Reload the firmware on the NXT. You may have to use the hidden reset button at the bottom of the "stud" hole underneath the USB port. Use a straigtened paper clip to push the button in. The NXT should be powered on first. Hold the button in for at least 10 to 15 seconds. You should be able to hear a very faint clicking from the NXT to indicate it is in boot mode. Then you can always reload firmware
- Uninstall and re-install ROBOTC
I would try the above in sequential order until one of them works.