The folks at Openschemes.com have written up an article on how to convert a USB serial port adapter to a low voltage serial interface for interfacing with microcontrollers. Though you can always just buy one, this is a fairly quick and cheap solution, especially if you are in a pinch or don’t have access to a retailer. The specific models you should watch for, are the ones with two chips, a microcontroller and a line translater.They go through the process of finding exactly where to patch in to add an extra interface. It only takes a couple wires and you are ready to go.
Not only can you use this as your serial connection to another microcontroller, but you can actually take control of the one on the board itself. If you load it with the drivers from TI, you gain access to the flash memory and can do whatever you want. They don’t go into much detail here though, stating that they’ll write another article on that.
We thought this little bugger looked familiar so we went digging through our archives. Sure enough, we found this system in action back in January of 2008.
[via Hacked Gadgets]