Start reading the scope after a falling trigger

Author: dplassgit

scope/scope.ino

@@ -2,23 +2,51 @@
 
 // potentiometer wiper (middle terminal) connected to analog pin 3
 // outside leads to ground and +5V
-int analogPin = A3; 
+int analogPin = A3;
+// Pin to trigger
+const int triggerPin = 2;
+
+int trigger = 0;
 int val = 0;  // variable to store the value read
+int shouldRead = 0;
+int ones = 0;
 
 void setup() {
-  Serial.begin(9600);
-  Serial.println("Hello scope");
+  pinMode(triggerPin, INPUT);
+
+  Serial.begin(1000000);
+  Serial.println("Hello trigger scope");
 }
 
 void loop() {
-  // read the analog port
-  // send back to the result as an appropriately formatted string
-  val = analogRead(analogPin);  // read the input pin
+  trigger = digitalRead(triggerPin);
+  if (!shouldRead && trigger == LOW) {
+    Serial.println("triggered");
+    shouldRead = 1;
+    ones = 0;
+  }
+  if (shouldRead) {
+    Serial.print("kb "); Serial.print(trigger); Serial.print(" Analog: ");
+  }
+  if (shouldRead && trigger == HIGH) {
+    // Stop reading after 30 ones in a row.
+    ones++;
+    if (ones == 300) {
+      Serial.println("untriggered");
+      shouldRead = 0;
+    }
+  }
+  if (shouldRead) {
+    // read the analog port
+    // send back to the result as an appropriately formatted string
+    val = analogRead(analogPin);  // read the input pin
 
-  // Scale to 80 chars wide, assuming a 10bit A/D
-  int width=80*(val/1024.0);
-  for (int x = 0; x < width; ++x) {
-    Serial.print(" ");
+    // Scale to 80 chars wide, assuming a 10bit A/D
+    int width = 80 * (val / 1024.0);
+    for (int x = 0; x < width; ++x) {
+      Serial.print(" ");
+    }
+    Serial.print("* ");
+    Serial.println(5.0*val/1024);          // debug value
   }
-  Serial.println(val);          // debug value
 }