From 3e251a82f6e8fd6fd2b4abe47dda8a5efaebf4ec Mon Sep 17 00:00:00 2001
From: Youen Toupin <youen.toupin@gmail.com>
Date: Wed, 3 May 2017 22:06:09 +0200
Subject: [PATCH] integrated Timer1 library (instead of custom code) ; but for
 an unknown reason it breaks the 1-wire communication (timer code doesn't work
 at all, or timings are wrong, or both) ; search algorithm is broken, and
 probably everything else as well

---
 LowLevel.h                | 31 -------------------------------
 OneWireIO.vcxproj         |  5 +++++
 OneWireIO.vcxproj.filters |  3 +++
 OneWireSlave.cpp          | 19 ++++++++++++-------
 4 files changed, 20 insertions(+), 38 deletions(-)

diff --git a/LowLevel.h b/LowLevel.h
index d18d387..94add00 100644
--- a/LowLevel.h
+++ b/LowLevel.h
@@ -27,39 +27,8 @@
 
 #if defined (__AVR_ATtiny85__)
 #define CLEARINTERRUPT GIFR |= (1 << INTF0)
-#include "UserTimer.h" //ATtiny-support based on TinyCore1 Arduino-core for ATtiny at http://github.com/Coding-Badly/TinyCore1.git
-__attribute__((always_inline)) static inline void UserTimer_Init( void )
-{
-	UserTimer_SetToPowerup();
-	UserTimer_SetWaveformGenerationMode(UserTimer_(CTC_OCR));
-}
-__attribute__((always_inline)) static inline void UserTimer_Run(short skipTicks)
-{
-	UserTimer_SetCount(0);
-	UserTimer_SetOutputCompareMatchAndClear(skipTicks);
-	UserTimer_ClockSelect(UserTimer_(Prescale_Value_64));
-}
-#define UserTimer_Stop() UserTimer_ClockSelect(UserTimer_(Stopped))
-
 #elif defined (__AVR_ATmega328P__)
 #define CLEARINTERRUPT EIFR |= (1 << INTF0)
-#define USERTIMER_COMPA_vect TIMER1_COMPA_vect
-
-__attribute__((always_inline)) static inline void UserTimer_Init( void )
-{
-	TCCR1A = 0;
-	TCCR1B = 0;
-	// enable timer compare interrupt
-	TIMSK1 |= (1 << OCIE1A);
-}
-__attribute__((always_inline)) static inline void UserTimer_Run(short skipTicks)
-{
-	TCNT1 = 0;
-	OCR1A = skipTicks;
-	// turn on CTC mode with 64 prescaler
-	TCCR1B = (1 << WGM12) | (1 << CS11) | (1 << CS10);
-}
-#define UserTimer_Stop() TCCR1B = 0
 #endif
 
 #elif defined(__MK20DX128__) || defined(__MK20DX256__)
diff --git a/OneWireIO.vcxproj b/OneWireIO.vcxproj
index 94ae257..020eccd 100644
--- a/OneWireIO.vcxproj
+++ b/OneWireIO.vcxproj
@@ -96,10 +96,15 @@ exit /B 1
     <ClCompile Include="OneWireSlave.cpp">
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
     </ClCompile>
+    <ClCompile Include="TimerOne.cpp">
+      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="config\known_16bit_timers.h" />
     <ClInclude Include="LowLevel.h" />
     <ClInclude Include="OneWireSlave.h" />
+    <ClInclude Include="TimerOne.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git a/OneWireIO.vcxproj.filters b/OneWireIO.vcxproj.filters
index 6f73395..885925e 100644
--- a/OneWireIO.vcxproj.filters
+++ b/OneWireIO.vcxproj.filters
@@ -2,10 +2,13 @@
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
     <ClCompile Include="OneWireSlave.cpp" />
+    <ClCompile Include="TimerOne.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="LowLevel.h" />
     <ClInclude Include="OneWireSlave.h" />
+    <ClInclude Include="TimerOne.h" />
+    <ClInclude Include="config\known_16bit_timers.h" />
   </ItemGroup>
   <ItemGroup>
     <CustomBuild Include="OneWireIO.ino" />
diff --git a/OneWireSlave.cpp b/OneWireSlave.cpp
index a7b752e..a3bf6b3 100644
--- a/OneWireSlave.cpp
+++ b/OneWireSlave.cpp
@@ -1,4 +1,5 @@
 #include "OneWireSlave.h"
+#include "TimerOne.h"
 
 // uncomment this line to enable sending messages along with errors (but takes more program memory)
 //#define ERROR_MESSAGES
@@ -68,9 +69,9 @@ void(*OneWireSlave::singleBitSentCallback_)(bool error);
 void(*OneWireSlave::logCallback_)(const char* message);
 
 
-ISR(USERTIMER_COMPA_vect) // timer1 interrupt
+void timer1Interrupt()
 {
-	UserTimer_Stop(); // disable clock
+	Timer1.detachInterrupt();
 	void(*event)() = timerEvent;
 	timerEvent = 0;
 	event();
@@ -98,7 +99,8 @@ void OneWireSlave::begin(const byte* rom, byte pinNumber)
 	pin_.writeLow(); // make sure the internal pull-up resistor is disabled
 
 	// prepare hardware timer
-	UserTimer_Init();
+	Timer1.initialize(4);
+	Timer1.stop();
 
 	// start 1-wire activity
 	beginWaitReset_();
@@ -234,16 +236,19 @@ byte OneWireSlave::crc8(const byte* data, short numBytes)
 void OneWireSlave::setTimerEvent_(short delayMicroSeconds, void(*handler)())
 {
 	delayMicroSeconds -= 10; // remove overhead (tuned on Arduino Uno)
+	if (delayMicroSeconds < 1)
+		delayMicroSeconds = 1;
 
-	short skipTicks = (delayMicroSeconds - 3) / 4; // round the micro seconds delay to a number of ticks to skip (4us per tick, so 4us must skip 0 tick, 8us must skip 1 tick, etc.)
-	if (skipTicks < 1) skipTicks = 1;
 	timerEvent = handler;
-	UserTimer_Run(skipTicks);
+	Timer1.attachInterrupt(timer1Interrupt);
+	Timer1.setPeriod(delayMicroSeconds);
+	Timer1.start();
 }
 
 void OneWireSlave::disableTimer_()
 {
-	UserTimer_Stop();
+	Timer1.stop();
+	Timer1.detachInterrupt();
 }
 
 void OneWireSlave::onEnterInterrupt_()