Version 1.1.0

Added wdt_reEnable() method to re-enable the wdt after a disable.

ReadMe.md

@@ -1,18 +1,16 @@
 # wdt_samd21 Library
-© 2022 Guglielmo Braguglia
+© 2022 Guglielmo Braguglia, updated on Jul 2022.
 
 ---
 
-
-
 A very simple library to activate, reset and deactivate the WDT on ATSAMD21.
 
 Based on the work of MartinL ([https://forum.arduino.cc/u/MartinL]()) on Arduino forum (Apr, 2018)
 
 &nbsp;&nbsp;&nbsp;• © 2022 Guglielmo Braguglia<br>
 &nbsp;&nbsp;&nbsp;• © 2018 MartinL
 
-The wdt_samd21 library allows, in a very easy way, on ATSAMD21 MCU, to **activate**, to periodically **reset** and to **deactivate** the WDT (*Watch Dog Timer*), which are the normal required functions for a simple use of the WDT for checking the correct execution of an application program.
+The wdt_samd21 library allows, in a very easy way, on ATSAMD21 MCU, to **activate**, to periodically **reset**,  to **deactivate** and to **reactivate** the WDT (*Watch Dog Timer*), which are the normal required functions for a simple use of the WDT for checking the correct execution of an application program.
 
 ### Library usage and initialization
 
@@ -78,18 +76,30 @@ wdt_reset ( );
 
 ##### wdt_disable( )
 
-Disable the WDT until it is reactivated again with a wdt_init( ).
+Disable the WDT until it is reactivated again with a wdt_reEnable( ).
 
 Example:
 
 ```
 wdt_disable ( );
 ```
 
+---
+
+##### wdt_reEnable( )
+
+Re-enable the WDT disabled by a previous wdt_disable( ).
+
+Example:
+
+```
+wdt_reEnable ( );
+```
+
 ---
 ### Demo Program
 
-The following example initializes the WDT for a timeout of 2 seconds, after which, in the loop(), it performs a for structure with a delay() of one second at each iteration, but sending a wdt_reset() command to the WDT to avoid the restart. At the end of the for structure, a 4 second delay() is performed which causes the MCU to restart so, all that following the delay(), is never executed.
+The following example initializes the WDT for a timeout of 2 seconds, after which, in the loop(), it performs a for structure with a delay() of one second at each iteration, but sending a wdt_reset() command to the WDT to avoid the restart. At the end of the for structure, the wdt is first disabled then, after a 3 second delay(), is enabled again and, finally, a 4 second delay() is performed which causes the MCU to restart so, all that following the last delay(), is never executed.
 
 ```
 #include <wdt_samd21.h>
@@ -118,14 +128,23 @@ void loop() {
       wdt_reset();
    }
    //
-   // now wait 4 seconds ... the WDT should restart the board
+   // now disable wdt and wait ...
+   wdt_disable();
+   Serial.println( "wdt disabled ..." );
+   Serial.println ( "Now waiting for 3 seconds ..." );
+   delay(3000);
+   //
+   // ... then reEnable the wdt ...
+   wdt_reEnable();
+   Serial.println( "wdt reEnabled ..." );
+   //
+   // ... and wait 4 seconds ... the WDT should restart the board
    Serial.println ( "Now waiting for 4 seconds ..." );
    delay ( 4000 );
    //
-   Serial.println ( "You will never see this message printed" );
+   Serial.println ( "*** You will never see this message printed ***" );
    delay ( 1000 );
 }
 ```
 
-
 ---

examples/wdt_samd21_demo/wdt_samd21_demo.ino

@@ -3,8 +3,8 @@
 void setup() {
    delay ( 500 );
    //
-   SerialUSB.begin ( 9600 );
-   while ( !SerialUSB ) {
+   Serial.begin ( 9600 );
+   while ( !Serial ) {
       delay ( 100 );
    }
    //
@@ -16,18 +16,28 @@ void loop() {
    for ( byte i = 0; i < 5; i++ ) {
       // wait a second
       delay ( 1000 );
-      // write on the native serial USB port
-      SerialUSB.print ( "Iteration " );
-      SerialUSB.print ( i + 1 );
-      SerialUSB.println ( " of 5" );
+      // write on the serial port
+      Serial.print ( "Iteration " );
+      Serial.print ( i + 1 );
+      Serial.println ( " of 5" );
       // "feed" the WDT to avoid restart
       wdt_reset();
    }
    //
-   // now wait 4 seconds ... the WDT should restart the board
-   SerialUSB.println ( "Now waiting for 4 seconds ..." );
+   // now disable wdt and wait ...
+   wdt_disable();
+   Serial.println( "wdt disabled ..." );
+   Serial.println ( "Now waiting for 3 seconds ..." );
+   delay(3000);
+   //
+   // ... then reEnable the wdt ...
+   wdt_reEnable();
+   Serial.println( "wdt reEnabled ..." );
+   //
+   // ... and wait 4 seconds ... the WDT should restart the board
+   Serial.println ( "Now waiting for 4 seconds ..." );
    delay ( 4000 );
    //
-   SerialUSB.println ( "You will never see this message printed" );
+   Serial.println ( "*** You will never see this message printed ***" );
    delay ( 1000 );
 }

keywords.txt

@@ -3,6 +3,7 @@ wdt_samd21	KEYWORD1
 wdt_init	KEYWORD2
 wdt_reset	KEYWORD2
 wdt_disable	KEYWORD2
+wdt_reEnable	KEYWORD2
 
 WDT_CONFIG_PER_8	LITERAL1
 WDT_CONFIG_PER_16	LITERAL1

library.properties

@@ -1,9 +1,9 @@
 name=wdt_samd21
-version=1.0.0
+version=1.1.0
 author=Guglielmo Braguglia <[email protected]>
 maintainer=Guglielmo Braguglia <[email protected]>
 sentence=A very simple library for the management of the WDT on ATSAMD21.
-paragraph=A simple library to activate, reset and deactivate the WDT on ATSAMD21. From the original work of MartinL (arduino forum: https://forum.arduino.cc/u/MartinL).
+paragraph=A simple library to activate, reset, deactivate and reactivate the WDT on ATSAMD21. From the original work of MartinL (arduino forum: https://forum.arduino.cc/u/MartinL).
 category=Device Control
 url=https://github.com/gpb01/wdt_samd21
 architectures=samd

src/wdt_samd.cpp

@@ -91,3 +91,13 @@ void wdt_disable ( void ) {
    REG_WDT_CTRL = WDT_CTRL_RESETVALUE;               // Disable the WDT in normal mode
    while ( WDT->STATUS.bit.SYNCBUSY );               // Wait for synchronization
 }
+
+// ------------------ wdt_reEnable ----------------------
+
+void wdt_reEnable ( void ) {
+   //
+   // Enable the WDT
+   while ( WDT->STATUS.bit.SYNCBUSY );               // Check if the WDT registers are synchronized
+   REG_WDT_CTRL = WDT_CTRL_ENABLE;                   // Enable the WDT in normal mode
+   while ( WDT->STATUS.bit.SYNCBUSY );               // Wait for synchronization
+}

src/wdt_samd21.h

@@ -46,10 +46,16 @@
 
 #include <Arduino.h>
 
+#if !defined (__SAMD21G18A__)
+#error "This library is only for SAMD21G18A, compilation aborted."
+#endif
+
 void wdt_init ( unsigned long wdt_config_per =  WDT_CONFIG_PER_2K );
 
 void wdt_reset ( void );
 
 void wdt_disable ( void );
 
+void wdt_reEnable ( void );
+
 #endif