I have just installed micrOS onto my TI 84+ CSE, and I opened up the port monitor. Now the calculator is frozen and I have pressed every key on the keyboard as well as the reset button on the back and still, nothing happens. If I am able to get the calculator to turn off, I know it will turn on fine, for I believe this is just a bug in micrOS, but because it is self hosted, there is no safety button.

At this point, I have no choice but to leave it on over night as the battery drains, forcing it to turn off so I can restart it. Is there a better way to do this? I have tried to remove the battery, but I do not know how to do this and I do not want to mess anything up. Also, the holes on the sides with screws in them are too small for my screw driver.

Just unplug the Li-Poly battery, then plug it back in, as you correctly guessed. There are no holes in the sides to remove the battery cover. You remove two Philips screws on the back to open the battery compartment.

Well, I'm too late for this, but. . . .

The RESET button on the back definitely works, but it can be hard to trigger without a paperclip. You need to press firmly. There is no way MicrOS can prevent it from resetting, as the reset is a hardware reset. The only way it could fail to reset the calculator is if there was something wrong with the contacts, or TI made a design change that breaks it.

I am aware of MicrOS still having a freezing bug, but as I said, the RESET button on the back cannot be disabled in software. I probably should have provided MicrOS as source-only, as it's really more of toy for programmers than a useful utility for end-users.


Actually, that will definitely break it harder. The hardware has no low-voltage protection, so leaving it on will ruin the battery, which probably now needs replacement. It happened to me once, too, and seems like a critical oversight from TI (don't ask firmware engineers to write critical OS code). Replacements are about $10-$20, which is a reasonable price for a LiPO cell. You'll know the battery needs replacement if the calculator only turns on momentarily, you can see a bad-battery icon flash, and the battery charging LED doesn't stay orange for very long. Sadly, the calculator will not let you attempt to power it exclusively from USB, with a bad or no battery connected.

As KermM said, you only need a generic screw driver to remove the two screws holding the battery cover on. The screw do not come out; they have an internal retainer so you don't lose them. Once removed, the panel should fall out if you hold the calculator with the panel facing down. If it does not after you are sure the two screws are completely loosed, use something such as stiff card stock to pry the cover off. To disconnect the battery, grasp the battery cable near where it connects to the calculator and pull slowly but firmly.

Thank you for the responses. Since I wrote this question late in the evening, I was not able to read the responses before I went to sleep. I did leave the calculator on over night and I do not see any problems yet, but now I know for next time.

And by the way, I really do think that micrOS is a neat project.