:: ed baafi :: mas863 :: how to make almost anything :: Communication

This week, I created a one wire bus using the fabduino. I came up with this technique a few years ago when looking for a bus for the Modkit project.. The idea is pretty simple: You connect to the bus with both the RX and TX pins of the onboard UART. This allows every node to talk and listen on the same wire. You get free collision detection by reading the byte you received against the byte you just sent. Of course, you shouldn't just connect each TX line to the bus directly as all the nodes will be pulling (or is it driving - have to check the datasheet) the line high. For Modkit we ended up using buffers for the TX line, but I revisited using a simpler setup including just a diode or a PMOS for my little bus modules this week.