Added firmware

Firmware/grandMA_fader_cmd_test/grandMA_fader_cmd.ino

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+/*
+  Analog input, analog output, serial output
+
+  Reads an analog input pin, maps the result to a range from 0 to 255 and uses
+  the result to set the pulse width modulation (PWM) of an output pin.
+  Also prints the results to the Serial Monitor.
+
+  The circuit:
+  - potentiometer connected to analog pin 0.
+    Center pin of the potentiometer goes to the analog pin.
+    side pins of the potentiometer go to +5V and ground
+  - LED connected from digital pin 9 to ground through 220 ohm resistor
+
+  created 29 Dec. 2008
+  modified 9 Apr 2012
+  by Tom Igoe
+
+  This example code is in the public domain.
+
+  https://www.arduino.cc/en/Tutorial/BuiltInExamples/AnalogInOutSerial
+*/
+
+// These constants won't change. They're used to give names to the pins used:
+const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
+const int analogOutPin = 9; // Analog output pin that the LED is attached to
+
+int sensorValue = 0;        // value read from the pot
+int outputValue = 0;        // value output to the PWM (analog out)
+
+void setup() {
+  // initialize serial communications at 9600 bps:
+  Serial.begin(9600);
+}
+
+void loop() {
+  // print the results to the Serial Monitor:
+  Serial.print(readOne(A0));
+  Serial.print(",");
+  Serial.print(readOne(A1));
+  Serial.print(",");
+  Serial.print(readOne(A2));
+  Serial.print(",");
+  Serial.print(readOne(A3));
+  Serial.print(",");
+  Serial.println(readOne(A4));
+
+  // wait 2 milliseconds before the next loop for the analog-to-digital
+  // converter to settle after the last reading:
+  delay(2);
+}
+
+int readOne(int inputPin){
+  sensorValue = constrain(analogRead(inputPin),5,1020);
+  outputValue = map(sensorValue, 5, 1020, 127,0);
+  return outputValue;
+}