Add WDT configuration

Author: adamgarbo

Diff for: libraries/WDT/examples/Example1_WDT_Basic/Example1_WDT_Basic.ino

@@ -1,6 +1,6 @@
 /*
   Author: Adam Garbo
-  Created: July 31st, 2020
+  Created: August 1st, 2020
   License: MIT. See SparkFun Arduino Apollo3 Project for more information
 
   This example demonstrates a simple configuration of the Artemis Watchdog Timer.
@@ -10,20 +10,23 @@
 
   The watchdog ISR provided will 'pet' the watchdog four times. On the fifth
   interrupt, the watchdog will not be pet, so the 'reset' action can occur.
-
   On the sixth timeout event, the WDT will issue a system reset, and the
   program will start over from the beginning.
 
+  The watchdogCounter will show the number of ticks before the watchdog
+  reset occurs.
+
   This example is based on the Ambiq SDK 2.4.2 watchdog.c example.
+  
+  Tested with SparkFun Artemis Redboard.
 */
 
 #include <WDT.h>
 
 APM3_WDT wdt;
 
 volatile bool watchdogFlag = false; // Watchdog Timer ISR flag
-volatile int watchdogCounter = 0; // Watchdog interrupt counter
-
+volatile int  watchdogInterrupt = 0; // Watchdog interrupt counter
 unsigned long currentMillis = 0,
               previousMillis = 0;
 
@@ -33,42 +36,47 @@ void setup() {
 
   Serial.println("Artemis Watchdog Timer Example");
 
-  // Configure the watchdog
-  wdt.configure(); // Default interrupt: 5 seconds. Default reset: 15 seconds
-  wdt.enable(); // Enable the watchdog
+  // Start the watchdog
+  wdt.start();
 }
 
-void loop() {
-
+void loop()
+{
   // Check for watchdog interrupts
-  if (watchdogFlag) {
-
+  if (watchdogFlag)
+  {
     // Calculate duration between watchdog interrupts
     currentMillis = millis() - previousMillis;
     previousMillis = millis();
 
-    Serial.print("Interrupt: "); Serial.print(watchdogCounter); 
-    Serial.print(" Period: "); Serial.println(currentMillis); Serial.print(" ms"); 
+    Serial.print("Interrupt: "); Serial.print(watchdogInterrupt);
+    Serial.print(" Period: "); Serial.print(currentMillis); Serial.println(" ms ");
+
+    if (watchdogInterrupt == 5) 
+    {
+      Serial.println("Warning: Watchdog has triggered a system reset");
+    }
   }
 
   watchdogFlag = false; // Clear watchdog flag
-  delay(10);
+  delay(1);
 }
 
 // Interrupt handler for the watchdog
-extern "C" void am_watchdog_isr(void) {
-
+extern "C" void am_watchdog_isr(void)
+{
   // Clear the watchdog interrupt
   wdt.clear();
 
   // Catch the first four watchdog interrupts, but let the fifth through untouched
-  if ( watchdogCounter < 4 ) {
+  if ( watchdogInterrupt < 4 )
+  {
     wdt.restart(); // "Pet" the dog
   }
   else {
-    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of imminent system reset
+    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of system reset trigger
   }
 
   watchdogFlag = true; // Set watchdog flag
-  watchdogCounter++; // Increment watchdog interrupt counter
+  watchdogInterrupt++; // Increment watchdog interrupt counter
 }

Diff for: libraries/WDT/examples/Example2_WDT_Config/Example2_WDT_Config.ino

@@ -1,42 +1,64 @@
 /*
   Author: Adam Garbo
-  Created: July 31st, 2020
+  Created: August 1st, 2020
   License: MIT. See SparkFun Arduino Apollo3 Project for more information
 
-  This example demonstrates how to modify the configuration of the Artemis 
+  This example demonstrates how to modify the configuration of the Artemis
   Watchdog Timer (WDT).
 
-  The code will configure the watchdog for both interrupt and reset generation,
-  and immediately start the watchdog timer.
+  The watchdog timer is controlled by a clock divider, interrupt ticks and 
+  reset ticks. To achieve desired watchdog timing, a simple calculation can be made:
 
+  period = # ticks / clock divider frequency 
+
+  Examples: 
+  128 interrupt ticks / 128 Hz clock = 1 second
+  64 interrupt ticks / 16 Hz clock = 4 seconds
+  32 interrupt ticks / 1 Hz clock = 32 seconds
+  16 interrupt ticks / 1/16 Hz clock = 256 seconds
+  
+  The following code will configure the watchdog for both interrupt and reset
+  generation, and immediately start the watchdog timer.
   The watchdog ISR provided will 'pet' the watchdog four times. On the fifth
   interrupt, the watchdog will not be pet, so the 'reset' action can occur.
-
   On the sixth timeout event, the WDT will issue a system reset, and the
   program will start over from the beginning.
 
   This example is based on the Ambiq SDK 2.4.2 watchdog.c example.
+
+  Tested with SparkFun Artemis Redboard.
 */
 
 #include <WDT.h>
 
 APM3_WDT wdt;
 
 volatile bool watchdogFlag = false; // Watchdog Timer ISR flag
-volatile int watchdogCounter = 0; // Watchdog interrupt counter
+volatile int watchdogInterrupt = 0; // Watchdog interrupt counter
 
 unsigned long currentMillis = 0,
               previousMillis = 0;
 
-void setup() 
+void setup()
 {
   Serial.begin(115200);
 
   Serial.println("Artemis Watchdog Timer Example");
 
   // Configure the watchdog
-  wdt.configure(); // Default interrupt: 5 seconds. Default reset: 15 seconds
-  wdt.start(); // Enable the watchdog
+  /*
+    Available watchdog timer clock dividers:
+    0 = Low Power Mode. This setting disables the watch dog timer
+    1 = 128 Hz 
+    2 = 16 Hz 
+    3 = 1 Hz
+    4 = 1/16th Hz
+  */
+  // Set watchdog timer clock to 128 Hz
+  // Set watchdog interrupt to 1 seconds (128 ticks / 128 Hz = 1 second)
+  // Set watchdog reset ~2 seconds (255 ticks / 128 Hz = 1.99 seconds)
+  wdt.configure(1, 128, 255); // Note: Ticks are limited to 255 (8-bit)
+  wdt.start(); // Start the watchdog
 }
 
 void loop()
@@ -48,11 +70,16 @@ void loop()
     currentMillis = millis() - previousMillis;
     previousMillis = millis();
 
-    Serial.print("Interrupt: "); Serial.print(watchdogCounter);
+    Serial.print("Interrupt: "); Serial.print(watchdogInterrupt);
     Serial.print(" Period: "); Serial.print(currentMillis); Serial.println(" ms");
+
+    // The watchdog configurations can also be set individually
+    wdt.setClock(2); // Set watchdog timer clock to 16 Hz
+    wdt.setInterrupt(64); // Set watchdog interrupt to 4 second (64 ticks / 16 Hz = 4 seconds)
+    wdt.setReset(96); // Set watchdog reset to 8 seconds (96 ticks / 16 Hz = 8 seconds)
   }
   watchdogFlag = false; // Clear watchdog flag
-  delay(10);
+  delay(1);
 }
 
 // Interrupt handler for the watchdog
@@ -61,16 +88,16 @@ extern "C" void am_watchdog_isr(void)
   // Clear the watchdog interrupt
   wdt.clear();
 
-  // Catch the first four watchdog interrupts, but let the fifth through untouched
-  if ( watchdogCounter < 4 )
+  // Catch the first eight watchdog interrupts, but let the ninth through untouched
+  if ( watchdogInterrupt < 8 )
   {
     wdt.restart(); // "Pet" the dog
   }
   else
   {
-    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of imminent system reset
+    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of system reset trigger
   }
 
   watchdogFlag = true; // Set watchdog flag
-  watchdogCounter++; // Increment watchdog interrupt counter
+  watchdogInterrupt++; // Increment watchdog interrupt counter
 }

Diff for: libraries/WDT/examples/Example3_WDT_LowPower/Example3_WDT_LowPower.ino

@@ -1,6 +1,6 @@
 /*
   Author: Adam Garbo
-  Created: July 31st, 2020
+  Created: August 1st, 2020
   License: MIT. See SparkFun Arduino Apollo3 Project for more information
 
   This example demonstrates the combined use of the Artemis Watchdog Timer (WDT)
@@ -9,11 +9,12 @@
   Both RTC and WDT interrupts will wake the system, print the date and time,
   and then re-enter deep sleep.
 
-  The code is configured to trigger the RTC alarm every minute and enter
-  deep sleep between interrupts. Alarm interupts also restart the WDT and reset
-  the watchdog counter.
-
-  If the WDT is not restarted after 75 seconds, a system reset will occur.
+  The WDT is configured to trigger every 10 seconds. If the WDT is not "pet" 
+  after 100 seconds, a system reset will be triggered.
+  
+  The RTC alarm is configured to trigger every minute and enter deep sleep 
+  between interrupts. Alarm interuptswill also restart the WDT and reset
+  the watchdog interrput counter.
 */
 
 #include <RTC.h>
@@ -24,49 +25,52 @@ APM3_WDT wdt;
 
 volatile bool alarmFlag = false; // RTC ISR flag
 volatile bool watchdogFlag = false; // Watchdog Timer ISR flag
-volatile int watchdogCounter = 0; // Watchdog interrupt counter
+volatile int watchdogInterrupt = 0; // Watchdog interrupt counter
 
 void setup()
 {
   Serial.begin(115200);
 
   Serial.println("Artemis Watchdog Low Power Example");
 
+  // Set the RTC time using UNIX Epoch time
+  rtc.setEpoch(1596240000); // Saturday, August 1, 2020 00:00:00
+
   // Set the RTC's alarm
   rtc.setAlarm(0, 0, 0, 0, 0, 0); // Set alarm (hund, ss, mm, hh, dd, mm)
   rtc.setAlarmMode(6); // Set the RTC alarm to trigger every minute
   rtc.attachInterrupt(); // Attach RTC alarm interrupt
 
-  // Configure the watchdog
-  wdt.configure(); // Default interrupt: 5 seconds. Default reset: 15 seconds
+  // Configure the watchdog timer
+  // See Example2_WDT_Config for more information on how to configure the watchdog
+  wdt.configure(2, 160, 240); // 16 Hz clock, 10-second interrupt period, 15-second reset period
 
-  // Enable the watchdog
-  wdt.enable();
+  // Start the watchdog
+  wdt.start();
 }
 
 void loop()
 {
   // Check for alarm interrupt
   if (alarmFlag)
   {
-    Serial.print("Alarm triggered: ");
+    Serial.print("Alarm interrupt: ");
     printDateTime(); // Print RTC's date and time
     alarmFlag = false;
 
     wdt.restart(); // "Pet" the dog
-    watchdogCounter = 0; // Reset watchdog interrupt counter
+    watchdogInterrupt = 0; // Reset watchdog interrupt counter
   }
 
   // Check for watchdog interrupt
   if (watchdogFlag)
   {
-    Serial.print("Watchdog triggered: ");
+    Serial.print("Watchdog interrupt: ");
     printDateTime(); // Print RTC's date and time
     watchdogFlag = false; // Clear watchdog flag
   }
 
   goToSleep(); // Enter deep sleep
-
 }
 
 // Print the RTC's current date and time
@@ -145,19 +149,20 @@ extern "C" void am_rtc_isr(void)
 }
 
 // Interrupt handler for the watchdog.
-extern "C" void am_watchdog_isr(void) {
-
+extern "C" void am_watchdog_isr(void)
+{
   // Clear the watchdog interrupt
   wdt.clear();
 
-  // Perform system reset after 15 watchdog interrupts (15 * 5 seconds = 75 seconds)
-  if ( watchdogCounter < 20 ) {
+  // Perform system reset after 10 watchdog interrupts (should not occur)
+  if ( watchdogInterrupt < 10 )
+  {
     wdt.restart(); // "Pet" the dog
   }
   else {
-    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of system reset
+    digitalWrite(LED_BUILTIN, HIGH); // Visual indication of system reset trigger
   }
 
   watchdogFlag = true; // Set the watchdog flag
-  watchdogCounter++; // Increment watchdog interrupt counter
+  watchdogInterrupt++; // Increment watchdog interrupt counter
 }

Diff for: libraries/WDT/keywords.txt

@@ -17,6 +17,11 @@ start		KEYWORD2
 stop		KEYWORD2
 restart		KEYWORD2
 clear		KEYWORD2
+getCounter	KEYWORD2
+configure	KEYWORD2
+setClock	KEYWORD2
+setInterrupt	KEYWORD2
+setReset	KEYWORD2
 
 #######################################
 # Constants (LITERAL1)

Diff for: libraries/WDT/src/WDT.cpp

@@ -1,21 +1,37 @@
-/*
-  
-*/
-
 #include "WDT.h"
 
 // Constructor
 APM3_WDT::APM3_WDT()
 {
     // The watchdog only runs off of the LFRC
     am_hal_clkgen_control(AM_HAL_CLKGEN_CONTROL_LFRC_START, 0);
+    am_hal_wdt_init(&watchdogConfig);
+}
+
+// Configure the watchdog timer
+void APM3_WDT::configure(uint8_t clock, uint8_t interrupt, uint8_t reset)
+{
+  WDT->CFG_b.CLKSEL = clock; 
+  WDT->CFG_b.INTVAL = interrupt; 
+  WDT->CFG_b.RESVAL = reset; 
+}
+
+// Set the LFRC clock frequency of the watchdog timer
+void APM3_WDT::setClock(uint8_t clock)
+{
+  WDT->CFG_b.CLKSEL = clock; 
 }
 
+// Set number of watchdog timer ticks allowed before a watchdog interrupt event is generated
+void APM3_WDT::setInterrupt(uint8_t interrupt)
+{
+  WDT->CFG_b.INTVAL = interrupt;   
+}
 
-// Configure the watchdog
-void APM3_WDT::configure()
+// Set number of watchdog timer ticks allowed before the watchdog will issue a system reset
+void APM3_WDT::setReset(uint8_t reset)
 {
-  am_hal_wdt_init(&watchdogConfig);
+  WDT->CFG_b.RESVAL = reset; 
 }
 
 // Enable the watchdog
@@ -46,4 +62,11 @@ void APM3_WDT::restart()
 void APM3_WDT::clear()
 {
   am_hal_wdt_int_clear();
-}
+}
+
+// Read the current value of watch dog timer counter register
+uint32_t APM3_WDT::getCounter()
+{
+  return am_hal_wdt_counter_get();
+}
+