What does the button do?

We’ve got 4 of these old programming kits, and for the last three years I’ve been wondering what the button does. We randomly press it when we’re bored, but I’ve never seen it do anything. Does anyone know?

Oh, and why is the cable like this? Why does it go through VGA, instead of just USB? This thing just never made sense, and I can’t find any documentation.

It puts the cortex (well the STM32 in the cortex) into flash programming mode, EasyC and ROBOTC do this for you so it’s not really needed.

It’s not VGA, that a 9 pin serial port that all PC’s had until perhaps 10 years ago.

Is it used for something in PROS or ConVex? Or is the button entirely useless?

Is the next version of the cable still going to have the “9 pin serial” port? It seems kind of pointless to me. Is it doing anything now?

Since the button immediately puts it in flash mode, it also immediately resets the PIC (not sure about cortex), effectively resetting all motors to 0 (also all sensor data is reset, if I remember correctly).

The cable is still the only way to program the PIC, and is the only way to program wirelessly via the joystick for the cortex (ROBOTC only). As far as seeing updated versions of the cable, doubtful as its uses are limited and not financially important.

No, it does not. It does still have the “PROGRAM” button.


The programming cable (the old one) has a small micro controller in it. The cortex can be made to go into download mode, or put into competition enabled/disabled state or autonomous/driver control modes when this micro controller sends a series of pulses on one of the connections to the joystick. See this post.


The pulses are created in response to commands being received from the PC or by pushing the button.

It has no more functionality with PROS or ConVEX.

Huh, I didn’t know it could act as a pseudo competition switch. How do you simulate the electrical impulses that you mentioned by pushing the button, though? Now that we have one I guess there’s no need for the information, but it would be nice not to need to find the thing to switch to Autonomous mode.

We used to use it to end autonomous mode when we were about to download.

We set up PIC to automatically start autonomous when turned on and pressing the buttom put it into download mode which stopped the robot.

This is 4 years ago obviously and now useless with wireless connections to competition switch.

We used to do that in my old high school team… I remember the mad rush to push the button before our robot crashed into something (or someone) because we forgot about autonomous! :smiley: