TeensyPUlseGenerator: Added option to wait for input signal

before sending a trigger.  Modified the firmware to work correctly.
Make it possible to reverse polarity for input and output in the firmware.

DeviceAdapters/TeensyPulseGenerator/CameraPulser.cpp

@@ -15,13 +15,15 @@ const uint32_t g_Max_MMVersion = 1;
 const char* g_versionProp = "Version";
 const char* g_Undefined = "Undefined";
 const char* g_IntervalBeyondExposure = "Interval-ms_on_top_of_exposure";
+const char* g_WaitForInputMode = "Wait_for_Input";
 
 
 const char* g_DeviceNameCameraPulser = "TeensySendsPulsesToCamera";
 
 CameraPulser::CameraPulser() :
    pulseDuration_(1.0),
    intervalBeyondExposure_(5.0),
+   waitForInput_(false),
    initialized_(false),
    version_(0),
    nrCamerasInUse_(0),
@@ -134,6 +136,17 @@ int CameraPulser::Initialize()
    pAct = new CPropertyAction(this, &CameraPulser::OnIntervalBeyondExposure);
    CreateFloatProperty(g_IntervalBeyondExposure, intervalBeyondExposure_, false, pAct);
 
+   // Trigger Mode property
+   uint32_t waitForInput;
+   ret = teensyCom_->GetWaitForInput(waitForInput);
+   if (ret != DEVICE_OK)
+      return ret;
+   waitForInput_ = (bool) waitForInput;
+   pAct = new CPropertyAction(this, &CameraPulser::OnWaitForInput);
+   CreateProperty(g_WaitForInputMode, waitForInput_ ? "On" : "Off", MM::String, false, pAct);
+   AddAllowedValue(g_WaitForInputMode, "Off");
+   AddAllowedValue(g_WaitForInputMode, "On");
+
    initialized_ = true;
 
    return DEVICE_OK;
@@ -825,3 +838,34 @@ int CameraPulser::OnIntervalBeyondExposure(MM::PropertyBase* pProp, MM::ActionTy
     }
     return DEVICE_OK;
 }
+
+int CameraPulser::OnWaitForInput(MM::PropertyBase* pProp, MM::ActionType eAct)
+{
+
+   if (eAct == MM::BeforeGet)
+   {
+      pProp->Set(waitForInput_ ? "On" : "Off");
+   }
+   else if (eAct == MM::AfterSet)
+   {
+      std::string waitForInput;
+      pProp->Get(waitForInput);
+      waitForInput_ = (waitForInput == "On");
+
+      // Send wait for input command if initialized
+      if (initialized_)
+      {
+         uint32_t sp = waitForInput_ ? 1 : 0;
+         uint32_t param;
+         int ret = teensyCom_->SetWaitForInput(sp, param);
+         if (ret != DEVICE_OK)
+            return ret;
+         if (param != sp)
+         {
+            GetCoreCallback()->LogMessage(this, "WaitforInput sent not the same as echoed back", false);
+            return ERR_COMMUNICATION;
+         }
+      }
+   }
+   return DEVICE_OK;
+}

DeviceAdapters/TeensyPulseGenerator/CameraPulser.h

@@ -65,6 +65,7 @@ class CameraPulser : public CCameraBase<CameraPulser>
    int OnVersion(MM::PropertyBase* pProp, MM::ActionType pAct);
    int OnPulseDuration(MM::PropertyBase* pProp, MM::ActionType eAct);
    int OnIntervalBeyondExposure(MM::PropertyBase* pProp, MM::ActionType eAct);
+   int OnWaitForInput(MM::PropertyBase* pProp, MM::ActionType eAct);
 
 private:
    bool ImageSizesAreEqual();
@@ -75,6 +76,7 @@ class CameraPulser : public CCameraBase<CameraPulser>
    std::string usedCamera_;
    double intervalBeyondExposure_; // Interval beyond exposure time in ms
    double pulseDuration_; // Pulse duration in milli-seconds
+   bool waitForInput_; // Whether to wait sending the pulse for the input to go high
    bool initialized_;
    unsigned int nrCamerasInUse_;
    ImgBuffer img_;

DeviceAdapters/TeensyPulseGenerator/TeensyPulseGenerator/TeensyPulseGenerator.ino

@@ -2,8 +2,15 @@
 
 static const uint32_t version = 1;
 
-uint8_t outputPin = LED_BUILTIN;  // LED_BUILTIN;
-uint8_t inputPin = 2;
+const uint8_t outputPin = LED_BUILTIN;  // Modify as desired.  Teensy LED: LED_BUILTIN;
+const bool activateOn = HIGH;             // set to LOW if required by device
+const uint8_t inputPin = 2;             // MOdify as desired
+const bool inputStateDeviceIsBusy = HIGH;  // set to LOW if required
+
+
+//  Do not modify below this line
+const int activate = activateOn;
+const int inActivate = !activateOn;
 
 /**
 Note: The pulse pin nr and input pin nr are hard coded.
@@ -58,27 +65,27 @@ private:
     IntervalTimer intervalTimer;
 
     // State tracking
-    volatile bool isPulseActive = false;
     volatile bool isReadyToTrigger = true;
     volatile bool countPulses = false;
+    volatile bool startOnTrigger = false;
     volatile uint32_t pulseNumber = 0;
 
     // Static callback methods for timer interrupts
     static PulseGenerator* volatile instancePtr;
 
+    const int inputEdge =  inputStateDeviceIsBusy == LOW ? RISING : FALLING;
+
     // Turn pulse off
     static void stopPulseISR() {
         if (instancePtr) {
-            digitalWriteFast(instancePtr->outputPin, LOW);
-            instancePtr->isPulseActive = false;
+            digitalWriteFast(instancePtr->outputPin, inActivate);
             instancePtr->pulseTimer.end();
         }
     }
 
-    static inline void pulse() {
+    static inline void pulseISR() {
       // Generate pulse
-      digitalWriteFast(instancePtr->outputPin, HIGH);
-      instancePtr->isPulseActive = true;
+      digitalWriteFast(instancePtr->outputPin, activate);
       instancePtr->isReadyToTrigger = false;
       instancePtr->pulseNumber++;
 
@@ -91,18 +98,22 @@ private:
         if (instancePtr) {
             instancePtr->isReadyToTrigger = true;
             // If waiting for trigger and trigger not received, do nothing
-            if (instancePtr->waitForTrigger &&  digitalReadFast(instancePtr->triggerPin) == LOW) {
+            if (instancePtr->waitForTrigger &&  digitalReadFast(instancePtr->triggerPin) == inputStateDeviceIsBusy) {
                 return;
             }
-            pulse();
+            pulseISR();
         }
     }
 
     // Trigger pin interrupt handler
     static void triggerPinISR() {
-        if (instancePtr && instancePtr->waitForTrigger && instancePtr->isReadyToTrigger) {
-            pulse();
-        }
+      if (instancePtr && instancePtr->startOnTrigger) {
+        instancePtr->intervalTimer.begin(instancePtr->intervalISR, instancePtr->pulseInterval);
+        instancePtr->startOnTrigger = false;
+      }
+      if (instancePtr && instancePtr->waitForTrigger && instancePtr->isReadyToTrigger) {
+          pulseISR();
+      }
     }
 
 public:
@@ -117,11 +128,11 @@ public:
           pulseNumber(0) {
         instancePtr = this;
         pinMode(outputPin, OUTPUT);
-        digitalWriteFast(outputPin, LOW);
+        digitalWriteFast(outputPin, inActivate);
 
         if (triggerPin != 255) {
             pinMode(triggerPin, INPUT_PULLDOWN);
-            attachInterrupt(digitalPinToInterrupt(triggerPin), triggerPinISR, RISING);
+            attachInterrupt(digitalPinToInterrupt(triggerPin), triggerPinISR, inputEdge);
         }
     }
 
@@ -208,17 +219,16 @@ public:
     }
 
     void reportNumberOfPulses() {
-      Serial.write(6);
       noInterrupts();
       uint32_t number = numberOfPulses;
       interrupts();
+      Serial.write(6);
       Serial.write((byte *) &number, 4);
     }
 
     void start() {
         // Reset state
         isReadyToTrigger = true;
-        isPulseActive = false;
         isRunning = true;
 
         // Stop any existing timers
@@ -228,12 +238,19 @@ public:
         stopPulseISR();
 
         // no timers running, so we can set volatile variables without interupting interrupts
+        noInterrupts();  // Note that triggerPinISR is always running
         pulseNumber = 0;
+        interrupts();
 
         // Start interval timer to manage pulse cycles
         // start first pulse here, otherwise we would wait pulseInterval for the first pulse
-        intervalTimer.begin(intervalISR, pulseInterval);
-        pulse();
+
+        if (waitForTrigger && digitalReadFast(triggerPin) == inputStateDeviceIsBusy) {
+          startOnTrigger = true;
+        } else {
+          intervalTimer.begin(intervalISR, pulseInterval);
+          pulseISR();
+        }
 
         // Simplified start confirmation
         Serial.write(1);
@@ -266,8 +283,7 @@ public:
 
         // Reset state
         isRunning = false;
-        isPulseActive = false;
-        isReadyToTrigger = true;
+        isReadyToTrigger = false;
     }
 
     void stop() {
@@ -282,14 +298,11 @@ public:
         // Only run if active
         noInterrupts();
         bool active = isRunning;
+        bool stop = countPulses && pulseNumber == numberOfPulses;
         interrupts();
         if (!active) 
           return;
 
-        noInterrupts();
-        bool stop = countPulses && pulseNumber == numberOfPulses;
-        interrupts();
-
         if (stop) {
           stopNoSerialMessage();
           return;
@@ -407,11 +420,14 @@ void setup() {
     // Give some time for serial to initialize
     delay(1000);
 
+    pinMode(inputPin, INPUT_PULLUP);
+    pinMode(outputPin, OUTPUT);
+
     // Create pulse generator on pin 13 with optional trigger on pin 12
     pulsegen = new PulseGenerator(outputPin, inputPin);
 
     // Configure initial defaults
-    pulsegen->configure(50000, 500000, 0, false);
+    pulsegen->configure(1000, 100000, 0, false);
 }
 
 void loop() {