# Serial Ports 

Grove Connector: J5 (On the right, as you look at the connectors)
 Pin 1: UART2_RXD   = P9_22 (right-most grove pin)
 Pin 2: UART2_TXD   = P9_21
 Pin 3: VDD_3V3B
 Pin 4: DGND                (left-most grove pin)

1. Wiring
	- Connect P9_22 to P9_21 (shorting them together; called a loop-back)

2. Software Setup (on BBG)
	sudo config-pin p9.22 uart
	sudo config-pin p9.21 uart

3. Run screen to view (on BBG)
	sudo apt-get install screen
	sudo screen /dev/ttyS2 9600
	
	Type into screen and you should see your characters echo'd back.
	Disconnect the loop-back connection and you should see the echo stop.
	
	Note: P9_22 is connected to the Zen cape's buzzer. So, as you receive
	characters you'll hear the buzzer click. This is OK. However, you can
	stop this clicking by removing the jumper J3 (beside the round black
	buzzer on the zen.
	
Now that you know the serial port works, you can unplug the loopback
connection we used and instead plug in your serial  device to the Grove
port J5. You may need to change the speed of the serial port used by
Screen to match what your device will do.