I was looking at the Vex Programming Hardware kit, and it looks like it is just a USB-to-Serial adapter. Since my laptop has a serial port, I was looking at making a DIY RS-232 to RJ-12 adapter, so I can debug and program my robot wirelessly. However, I’d need to know the pinout of the RJ-12 port on the controller in order to do this.
I’d appreciate any help, as the kit is $50, while this would end up being less than $5.
Yea, don’t connect a standard RS232 serial port to the joystick, bad things may happen. The programming cable has two functions.
It does a level shift from standard RS232 levels to TTL levels.
It does some magic that places the cortex into download mode (at least with the old cable) that’s what the extra button on the cable also does if the interface to the PC has issues (like too many printf statements being used and saturating the serial channel).
If this was easy DIY cables would have been made years ago.
I’m currently working on a custom programming cable using something like this and I’m currently able to download and debug over it. I don’t have access to it right this moment and will probably make a proper post after worlds when I finally have the time. I found the pinout from these 12 sources. Be careful if you decide to try anything as you don’t want to damage a joysticks because while the programming kits are expensive, the joysticks cost quite a bit more.