From 9d0dac76689aa84c62e0356b0b2bc05cab9dce6c Mon Sep 17 00:00:00 2001
From: Jason Milldrum <milldrum@gmail.com>
Date: Mon, 15 Jan 2018 17:22:20 -0800
Subject: [PATCH] Add support for no output pin toggling

---
 README.md     |  5 +++--
 src/Morse.cpp | 28 ++++++++++++++++++++++------
 src/Morse.h   |  1 -
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index dbc240e..684a2bd 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ If you need to check to see if the Morse library is currently sending the conten
 
 The sending speed can be changed on-the-fly by using the _setWPM()_ method. The parameter is typed using a _float_ so that fractional words per minute can be specified. Why would you want to do this? In case you need to send Morse code using a very long integration time such as with the QRSS operating mode. For example, a setting of 0.2 WPM sets a Morse code "dit" length of 6 seconds.
 
-If you don't want to have the library directly control a digital I/O pin, you may have your sketch poll the boolean _tx_ member variable and act on it accordingly within their periodic 1 ms function.
+If you don't want to have the library directly control a digital I/O pin, you may have your sketch poll the boolean _tx_ member variable and act on it accordingly within their periodic 1 ms function. Set the output pin parameter in the constructor to 0.
 
 Startup Conditions and Constraints
 ----------------------------------
@@ -61,7 +61,8 @@ Public Methods
  *
  * Create an instance of the Morse class.
  *
- * tx_pin - Arduino pin used as the output by this library.
+ * tx_pin - Arduino pin used as the output by this library. Will not toggle an
+ *          output pin if set to 0.
  * init_wpm - Sending speed in words per minute.
  *
  */
diff --git a/src/Morse.cpp b/src/Morse.cpp
index d1b332b..27ab094 100644
--- a/src/Morse.cpp
+++ b/src/Morse.cpp
@@ -36,7 +36,8 @@
  *
  * Create an instance of the Morse class.
  *
- * tx_pin - Arduino pin used as the output by this library.
+ * tx_pin - Arduino pin used as the output by this library. Will not toggle an
+ *          output pin if set to 0.
  * init_wpm - Sending speed in words per minute.
  *
  */
@@ -48,7 +49,10 @@ Morse::Morse(uint8_t tx_pin, float init_wpm) : output_pin(tx_pin)
 
 	setWPM(init_wpm);
 
-	pinMode(output_pin, OUTPUT);
+	if(output_pin)
+	{
+		pinMode(output_pin, OUTPUT);
+	}
 
 	cur_state = State::IDLE;
 	next_state = State::IDLE;
@@ -223,7 +227,10 @@ void Morse::update()
     case State::PREAMBLE:
       // Transmitter on
       tx = true;
-			digitalWrite(output_pin, HIGH);
+			if(output_pin)
+			{
+				digitalWrite(output_pin, HIGH);
+			}
 
       // When done waiting, go back to IDLE state to start the message
       if(cur_timer > cur_state_end)
@@ -235,12 +242,18 @@ void Morse::update()
     case State::DIT:
     case State::DAH:
       tx = true;
-			digitalWrite(output_pin, HIGH);
+			if(output_pin)
+			{
+				digitalWrite(output_pin, HIGH);
+			}
 
       if(cur_timer > cur_state_end)
       {
         tx = false;
-				digitalWrite(output_pin, LOW);
+				if(output_pin)
+				{
+					digitalWrite(output_pin, LOW);
+				}
 
         cur_state_end = cur_timer + dit_length;
         cur_state = State::DITDELAY;
@@ -252,7 +265,10 @@ void Morse::update()
 		case State::MSGDELAY:
     case State::EOMDELAY:
       tx = false;
-			digitalWrite(output_pin, LOW);
+			if(output_pin)
+			{
+				digitalWrite(output_pin, LOW);
+			}
 
       if(cur_timer > cur_state_end)
       {
diff --git a/src/Morse.h b/src/Morse.h
index 49e9587..aec69a7 100644
--- a/src/Morse.h
+++ b/src/Morse.h
@@ -28,7 +28,6 @@
 
 #include "Arduino.h"
 
-
 // Constants
 constexpr uint8_t DEFAULT_OUTPUT_PIN = LED_BUILTIN;
 constexpr float DEFAULT_WPM = 25;