title: UART vs I2C vs SPI for inter-processor communication between microcontrollers
body: <p>I am examining a way to connect two microcontrollers. On the level of serialization I am thinking of using Nano protobuffers (<a href="http://code.google.com/p/nanopb/">http://code.google.com/p/nanopb/</a>). This way I can encode/decode messages and send them between two processors.</p>
  
  <p>Basically, one small processor would be the RPC server, capable of doing several functions. Bigger processor will call there RPCs via messages sent, and then when data is ready, it will read it from smaller processor.</p>
  
  <p>What would be the pros/cons of using UART, I2C or SPI?</p>
  
  <p>Messages will be put in the mailbox que prior to sending.</p>
  
  <p>Best regards,
  Drasko</p>