avr: added devices, more work on modules.

avr/modules/com2/README

@@ -3,14 +3,14 @@ This is the inter-node communication protocol.
 Hardware
 ========
 
-AqHome uses asynchronous serial communication, nodes are connected via a 4 lines:
-- 5V
-- GND
-- DATA (0V/3.3V)
-- ATTN (0V/3.3V)
+AqHome uses asynchronous serial communication, nodes are connected via 4 lines:
+- 5V               [red]
+- GND              [black]
+- DATA (0V/3.3V)   [green]
+- ATTN (0V/3.3V)   [blue]
 
 DATA and ATTN are only pulled low by nodes on the bus, never pulled high, this allows for multi-master
-mode. Every node sends data at will.
+mode. Every node sends data at will (after checking for free line).
 
 
 5V, GND