From ae3dd3215db0184634c91ef05fdb8419be39275f Mon Sep 17 00:00:00 2001
From: paynterf <paynterf@gmail.com>
Date: Fri, 10 Jul 2020 23:34:16 -0400
Subject: [PATCH 1/4] Added code to demonstrate use of new I2C timeout feature

---
 .../Wire/examples/i2c_scanner/i2c_scanner.ino    | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
index 3febbf441..bef1cdbe4 100644
--- a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
+++ b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
@@ -21,6 +21,8 @@
 //    A sensor seems to use address 120.
 // Version 6, November 27, 2015.
 //    Added waiting for the Leonardo serial communication.
+// Version 6, July 10, 2020 by G. Frank Paynter
+//    Demonstrates the use of the new Wire library timeout feature
 //
 //
 // This sketch tests the standard 7-bit addresses
@@ -29,15 +31,29 @@
 
 #include <Wire.h>
 
+uint16_t wireTimeoutCount; //capture I2C bus timeout events
+
 void setup() {
   Wire.begin();
 
   Serial.begin(9600);
   while (!Serial); // Leonardo: wait for serial monitor
   Serial.println("\nI2C Scanner");
+
+  Wire.setWireTimeout(3000, true); //timeout value in uSec, true to reset I2C bus on timeout
+  wireTimeoutCount = 0;
+  Wire.clearWireTimeoutFlag();
+
 }
 
 void loop() {
+  if (Wire.getWireTimeoutFlag())
+  {
+      wireTimeoutCount++;
+      Wire.clearWireTimeoutFlag();
+      Serial.print("Wire timeout detected; count now "); Serial.println(wireTimeoutCount);
+  }
+
   int nDevices = 0;
 
   Serial.println("Scanning...");

From 8aa1cef9fa0a622a12ecb76213c62e3f93abfb6a Mon Sep 17 00:00:00 2001
From: paynterf <paynterf@gmail.com>
Date: Thu, 16 Jul 2020 11:00:40 -0400
Subject: [PATCH 2/4] Move anti-lockup code to beginning of Setup()

---
 libraries/Wire/examples/i2c_scanner/i2c_scanner.ino | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
index bef1cdbe4..aca985a05 100644
--- a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
+++ b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
@@ -36,14 +36,14 @@ uint16_t wireTimeoutCount; //capture I2C bus timeout events
 void setup() {
   Wire.begin();
 
-  Serial.begin(9600);
-  while (!Serial); // Leonardo: wait for serial monitor
-  Serial.println("\nI2C Scanner");
-
+  //demonstrates use of new anti-lockup feature
   Wire.setWireTimeout(3000, true); //timeout value in uSec, true to reset I2C bus on timeout
   wireTimeoutCount = 0;
-  Wire.clearWireTimeoutFlag();
+  Wire.clearWireTimeoutFlag(); //should be cleared on startup, but...
 
+  Serial.begin(9600);
+  while (!Serial); // Leonardo: wait for serial monitor
+  Serial.println("\nI2C Scanner");
 }
 
 void loop() {

From b9a9ab35ae9a0a7262792e824d6155ce25292141 Mon Sep 17 00:00:00 2001
From: paynterf <paynterf@gmail.com>
Date: Thu, 16 Jul 2020 11:27:08 -0400
Subject: [PATCH 3/4] Remove 'clearWireTimeoutFlag()' from setup.  It is
 explicitly cleared in 'SetTimeout()'

---
 libraries/Wire/examples/i2c_scanner/i2c_scanner.ino | 1 -
 1 file changed, 1 deletion(-)

diff --git a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
index aca985a05..7dd83adf7 100644
--- a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
+++ b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
@@ -39,7 +39,6 @@ void setup() {
   //demonstrates use of new anti-lockup feature
   Wire.setWireTimeout(3000, true); //timeout value in uSec, true to reset I2C bus on timeout
   wireTimeoutCount = 0;
-  Wire.clearWireTimeoutFlag(); //should be cleared on startup, but...
 
   Serial.begin(9600);
   while (!Serial); // Leonardo: wait for serial monitor

From cf81cfc522fcb074f8ac2700ad07f1d1cad8db74 Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <matthijs@stdin.nl>
Date: Sat, 26 Sep 2020 21:37:16 +0200
Subject: [PATCH 4/4] Add check for WIRE_HAS_TIMEOUT

---
 libraries/Wire/examples/i2c_scanner/i2c_scanner.ino | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
index 7dd83adf7..8029c45eb 100644
--- a/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
+++ b/libraries/Wire/examples/i2c_scanner/i2c_scanner.ino
@@ -36,9 +36,11 @@ uint16_t wireTimeoutCount; //capture I2C bus timeout events
 void setup() {
   Wire.begin();
 
-  //demonstrates use of new anti-lockup feature
+  #if defined(WIRE_HAS_TIMEOUT)
+  // Prevent lockups on bus problems by aborting after a timeout
   Wire.setWireTimeout(3000, true); //timeout value in uSec, true to reset I2C bus on timeout
   wireTimeoutCount = 0;
+  #endif
 
   Serial.begin(9600);
   while (!Serial); // Leonardo: wait for serial monitor
@@ -46,12 +48,14 @@ void setup() {
 }
 
 void loop() {
+  #if defined(WIRE_HAS_TIMEOUT)
   if (Wire.getWireTimeoutFlag())
   {
       wireTimeoutCount++;
       Wire.clearWireTimeoutFlag();
       Serial.print("Wire timeout detected; count now "); Serial.println(wireTimeoutCount);
   }
+  #endif
 
   int nDevices = 0;