From cf5f36b50339f8ee8530503dada04b70ca6480d7 Mon Sep 17 00:00:00 2001
From: Youen Toupin <youen.toupin@gmail.com>
Date: Sat, 8 Aug 2015 22:36:24 +0200
Subject: [PATCH] improved high-level protocol

---
 OneWireIO.ino | 66 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 61 insertions(+), 5 deletions(-)

diff --git a/OneWireIO.ino b/OneWireIO.ino
index e3abba5..1e65415 100644
--- a/OneWireIO.ino
+++ b/OneWireIO.ino
@@ -15,6 +15,19 @@ Pin led(LEDPin);
 byte owROM[7] = { 0xE2, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 };
 
 byte acknowledge = 0x42;
+byte commandCheckError = 0xF1;
+
+int turnOnTimeoutSeconds = 5 * 60;
+
+const byte CMD_TurnOn = 0x01;
+const byte CMD_TurnOff = 0x02;
+const byte CMD_ReadState = 0x03;
+
+const byte ANS_StateIsOn = 0x01;
+const byte ANS_StateIsOff = 0x02;
+
+volatile byte command = 0x0;
+volatile long turnOnStartTime = 0;
 
 void owReceive(OneWireSlave::ReceiveEvent evt, byte data);
 
@@ -33,6 +46,13 @@ void loop()
 {
 	delay(1);
 
+	long now = millis();
+	if (now > turnOnStartTime + (long)turnOnTimeoutSeconds * 1000 || now < turnOnStartTime)
+	{
+		led.writeLow();
+		turnOnStartTime = 0;
+	}
+
 	cli();//disable interrupts
 	#ifdef ENABLE_SERIAL_CHANNEL
 	SerialChannel::swap();
@@ -49,11 +69,47 @@ void owReceive(OneWireSlave::ReceiveEvent evt, byte data)
 	switch (evt)
 	{
 	case OneWireSlave::RE_Byte:
-		if (data == 0x01)
-			led.writeHigh();
-		else if (data == 0x02)
-			led.writeLow();
-		OneWire.write(&acknowledge, 1, 0);
+		if (command == 0x00)
+		{
+			command = data;
+		}
+		else
+		{
+			if (data == (0xFF-command)) // to check there is no communication error, the master must send the command, and then its inverse
+			{
+				byte receivedCommand = command;
+				command = 0x0;
+				switch (receivedCommand)
+				{
+				case CMD_TurnOn:
+					turnOnStartTime = millis();
+					led.writeHigh();
+					OneWire.write(&acknowledge, 1, NULL);
+					break;
+				case CMD_TurnOff:
+					led.writeLow();
+					turnOnStartTime = 0;
+					OneWire.write(&acknowledge, 1, NULL);
+					break;
+				case CMD_ReadState:
+					bool state = led.read();
+					static byte response[2];
+					response[0] = state ? ANS_StateIsOn : ANS_StateIsOff;
+					response[1] = 0xFF - response[0];
+					OneWire.write(response, 2, NULL);
+					break;
+				}
+			}
+			else
+			{
+				command = 0x0;
+				OneWire.write(&commandCheckError, 1, NULL);
+			}
+		}
+		break;
+	case OneWireSlave::RE_Reset:
+	case OneWireSlave::RE_Error:
+		command = 0x0;
 		break;
 	default:
 		;