Add i2c-communication example (#90)

There very well may be a better way to do this. I'm more of a java dev
than a python dev, so please feel free to tear this apart.

Specifically, Java requires a few calls to convert the String to a
char[] then to a byte[]. Here, I've simply converted the string to a
bytearray.

I'm also using I2C.writeBulk() instead of I2C.transaction() per the
docstring on the transaction method. I can switch it back if you prefer.

---------

Co-authored-by: David Vo <[email protected]>

Author: fletch3555

i2c-communication/robot.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+"""
+    This is a sample program demonstrating how to communicate to a light controller from the robot
+    code using the roboRIO's I2C port.
+"""
+
+import wpilib
+
+
+class MyRobot(wpilib.TimedRobot):
+    PORT = wpilib.I2C.Port.kOnboard
+    DEVICE_ADDRESS = 4
+
+    def robotInit(self):
+        """Robot initialization function"""
+
+        self.arduino = wpilib.I2C(self.PORT, self.DEVICE_ADDRESS)
+
+    def writeString(self, s: str):
+        # Creates a char array from the input string
+        chars = s.encode("ascii")
+
+        # Writes bytes over I2C
+        self.arduino.writeBulk(chars)
+
+    def robotPeriodic(self):
+        # Creates a string to hold current robot state information, including
+        # alliance, enabled state, operation mode, and match time. The message
+        # is sent in format "AEM###" where A is the alliance color, (R)ed or
+        # (B)lue, E is the enabled state, (E)nabled or (D)isabled, M is the
+        # operation mode, (A)utonomous or (T)eleop, and ### is the zero-padded
+        # time remaining in the match.
+        #
+        # For example, "RET043" would indicate that the robot is on the red
+        # alliance, enabled in teleop mode, with 43 seconds left in the match.
+        allianceString = "U"
+        alliance = wpilib.DriverStation.getAlliance()
+        if alliance is not None:
+            allianceString = (
+                "R" if alliance == wpilib.DriverStation.Alliance.kRed else "B"
+            )
+
+        enabledString = "E" if wpilib.DriverStation.isEnabled() else "D"
+        autoString = "A" if wpilib.DriverStation.isAutonomous() else "T"
+        matchTime = wpilib.DriverStation.getMatchTime()
+
+        stateMessage = f"{allianceString}{enabledString}{autoString}{matchTime:03f}"
+
+        self.writeString(stateMessage)
+
+
+if __name__ == "__main__":
+    wpilib.run(MyRobot)

run_tests.sh

@@ -19,6 +19,7 @@ BASE_TESTS="
   game-data
   getting-started
   gyro
+  i2c-communication
   magicbot-simple
   mecanum-drive
   mecanum-driveXbox