So I designed a PCB which consists of an atmega328 controlling a digital potentiometer (MCP4131) using SPI. I stupidly connected the pot's i/o to the MISO (master in, slave out) pin on the arduino instead of the MOSI (master out, slave in) pin. The SS and SCK pins are connected correctly. Needless to say, I haven't been able to make the pot behave as it should, because i can't get the arduino to talk to it.
I tried going into the Arduino SPI library and, in the function begin(), changing the line
But, this doesn't do the trick. On my scope, I can see the bits being sent when the pot is hooked up properly (on my breadboard). If I could rip up the trace on my PCB and solder a jumper to the right pin on the arduino, that would be a fine workaround. But I'd rather be able to do it in software.
I don't have much experience with SPI. I'm currently researching it but haven't found anything useful on the web. Any thoughts on making the MISO pin switch to "MOSI"?