Using an older microcontroller?

Appreciate it. It gives me something to tinker with. I was thinking of giving the kit away to my nephew as he’s taken to building and creating things. But I wanted to first check what worked and what didn’t.

I’m not having much luck with RobotC so far. I see you can set the target to VEX Cortex 2.0. But I’m not even sure what model mine is… Version 1 perhaps?

Might have to try an older version…

Wonder if I have to update any firmware as well… (Not even sure that’s possible any more?)

You’ll need the really old ROBOTC, the 4.0 one may not support these. @Sylvie might be able to help, I think he programs some old PIC based VEX stuff.


I’m not finding a name for the controller. The docs I have just says “Vex Micro Controller Module”.

And… it had a whining noise when its turned on and controlled via the remote control. Silent when I disconnect the remote control though… :thinking:

It’s a PIC v.5 VEX microcontroller.
Scroll down the page - I think you need version 3.63


This is a PIC Microcontroller (v0.5). @Foster would know where to find the correct version of robotC

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@calvc01 was on it, The version is marked for the 0.5 system.

You’re right, I didn’t see that.

That you all very much. I’ll try the 3.63 version tomorrow.

“0.5” - is in version number? It’s so old it’s “beta” version number?

Yes, it’s very old.


I’ve downloaded v3.63. But I’m not sure how I can verify it’s working. Nothing comes up automatically when I plug in the PIC via the USB-serial cable.

Also, is there a way to fetch the program currently on the PIC?

And a way to check the firmware of the PIC?

The PIC system software has multiple parts.

There is two processors in the pic. The Master processor controls the access to the motor, transmitter, sensors, etc.

That program is has a suffix ending in .bin and it need to be loaded first

The second program controls the second processor and all of the use control functions. On the VEX site there is a pretty cool program that does this for you. That program ends in .hex. You should try to find and load it, it will give you the best instant driving checks.

So for basic functions you need the .bin and the ,hex program.

Lets move to RobotC. Robot C uses the .bin program since that talks to the motors/sensors/etc.

It has it’s own program for the user processor that it downloads. It also has a .hex ending. This special RobotC program talks to the RobotC program that you are writing and is how it gets downloaded and run.

I’d get the VEX software that works with the 0.5 hardware and download the basic .bin (master CPU) and .hex (user driver) control. I’d make sure that all of that works.

Then I’d get the RoborC stuf and download the ,bin file for that version, and the .hex file for the basic loader and then download a sample program.

All of this is one way downloads, there is no way to pull back the code that was downloaded.

Good luck!


Good to know.

Before I start messing with this; is the logic for the remote control tied to the current program on the PIC? If so, anyone knows what the default program is? I’d like to make backups just in case.

The instructions for the “default” program is here

Plus all the stuff you need to know about motors, metal, gears, etc.

The robot C stuff is here: for the drivers and the specific PIC version is found here


Great that all this information is still available! :grinning:

Thank you all again for your assistance! :+1::+1:

Dear thomthom, I’m wondering if you can help me locate connectors for this controller.

What exactly do you mean “connectors?”
Most of the information can be found on the VEX Website’s product page: VEX ARM® Cortex®-based Microcontroller - VEX Robotics

If u need help with a sensor let me know but you should be able to figure it out in the graphical interface of ROBOTC, since I doubt the IDE will allow you to select a non-analog sensor in the analog port in the motor and sensors setup. And from that you can figure out if a sensor is analog or digital for which port to plug it into.

Connor, first of all, I want to thank you for taking time to respond to my question. What I mean is the three wire connectors that plug into the microcontroller analog/digital, interrupt, and motor ports to connect to sensors and motors and such. Thank you for your help wise sage…

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Two and three wire cables can be found on the Vex robotics website here:

Robosource has repair parts for wires here: VEX Wire & Connector Repair Parts & Tools. Inexpensive, Easy Fixes for Plugs & Pins -


kmmohn, thank you so much for taking time to help me. Much, much appreciated. I know this is practically legacy equipment, but it still fascinates me, and I want to learn the ins and outs. Thank you again.