I've been coding on a seedstuido Rainbowduino board seen here: http://www.seeedstudio.com/depot/rainbowduino-led-driver-platform-atmega-328-p-371.html and Ive moved on and wanted to incorporate buttons so I could play games using the matrix. The only problem is when I hook everything up, none of the pins on the arduino work.
As far as wiring goes, Arduino->Rainbowduino:
Reset->DTR
TW->TX
RX->RX
5V->5V
GND->GND
in the IDE, i have to upload as an Arduino Nano w/ ATmega 328 for it to work(which I assume is the reason the pins aren't working), but when I try to upload as an Arduino Uno, i get "avrdude: stk500_getsync(): not in sync: resp=0x00" error.
Any help would be appreciated!
The problem is, that when you're wiring the two boards as described you're sending your sketches to the Rainbowduino and not your Arduino. The serial (UART) interface of the Rainbowduino is thought for firmware updates (at least in my version 2 of the board). But there is a I2C which is perfect for this kind of communication and does not interfere with sketch uploads. If you wanna use the UART interface you have to disconnect the Rainbowduino each time you wann upload sketches to the Arduino. And you probably have to cross the RX/TX lines.
You have two lines name "SDA" and "SCL", connect them to the same lines on the Arduino. Also connect the GND line and eventually the 5V lines too (if you power the Arduino from the Rainbowduino). That's all. Program the Arduino as I2C master, the Rainbowduino as I2C slave (I think to remember that some of the available firmwares for the Rainbowduino already includes such code).