Esp32 integration & percentage getter

README.md

@@ -52,6 +52,8 @@ PPMReader ppm(interruptPin, channelAmount);
 
 void setup() {
     Serial.begin(115200);
+    // Add the following line if you are using an ESP32 board :
+    // ppm.begin();
 }
 
 void loop() {

examples/PlotChannels/PlotChannels.ino → examples/PlotChannelsAVR/PlotChannelsAVR.ino

@@ -1,4 +1,6 @@
 /*
+This example is compatible with AVR boards.
+
 This example outputs values from all PPM channels to Serial
 in a format compatible with Arduino IDE Serial Plotter
 */

examples/PlotChannelsESP32/PlotChannelsESP32.ino

@@ -0,0 +1,29 @@
+/*
+This example is compatible with ESP32 Boards.
+
+This example outputs values from all PPM channels to Serial
+in a format compatible with Arduino IDE Serial Plotter
+*/
+
+#include <PPMReader.h>
+
+// Initialize a PPMReader on digital pin 3 with 6 expected channels.
+byte interruptPin = 3;
+byte channelAmount = 6;
+PPMReader ppm(interruptPin, channelAmount);
+
+void setup() {
+    Serial.begin(115200);
+    ppm.begin();
+}
+
+void loop() {
+    // Print latest valid values from all channels
+    for (byte channel = 1; channel <= channelAmount; ++channel) {
+        unsigned value = ppm.latestValidChannelValue(channel, 0);
+        Serial.print(value);
+        if(channel < channelAmount) Serial.print('\t');
+    }
+    Serial.println();
+    delay(20);
+}

src/PPMReader.cpp

@@ -20,6 +20,7 @@ along with PPM Reader.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "PPMReader.h"
 
+#define ABS(X) (X < 0? -X : X)
 PPMReader *PPMReader::ppm;
 
 void PPMReader::PPM_ISR(void) {
@@ -36,10 +37,12 @@ PPMReader::PPMReader(byte interruptPin, byte channelAmount):
     }
     // Attach an interrupt to the pin
     pinMode(interruptPin, INPUT);
+    #if !defined(ESP32)
     if(ppm == NULL) {
         ppm = this;
         attachInterrupt(digitalPinToInterrupt(interruptPin), PPM_ISR, RISING);
     }
+    #endif
 }
 
 PPMReader::~PPMReader(void) {
@@ -48,11 +51,21 @@ PPMReader::~PPMReader(void) {
     delete [] rawValues;
 }
 
+#if defined(ESP32)
+void PPMReader::begin()
+{
+    if(ppm == NULL) {
+        ppm = this;
+        attachInterrupt(digitalPinToInterrupt(interruptPin), PPM_ISR, RISING);
+    }
+}
+#endif 
+
 void PPMReader::handleInterrupt(void) {
     // Remember the current micros() and calculate the time since the last pulseReceived()
     unsigned long previousMicros = microsAtLastPulse;
     microsAtLastPulse = micros();
-    unsigned long time = microsAtLastPulse - previousMicros;
+    unsigned long time = ABS((unsigned)microsAtLastPulse - (unsigned)previousMicros);
 
     if (time > blankTime) {
         // Blank detected: restart from channel 1 
@@ -78,6 +91,39 @@ unsigned PPMReader::rawChannelValue(byte channel) {
     return value;
 }
 
+unsigned PPMReader::percentageChannelValue(byte channel){
+    unsigned raw = rawChannelValue(channel);
+
+    if(raw >= minChannelValue && raw <= maxChannelValue)
+    {
+        return map(raw, minChannelValue, maxChannelValue, 0, 100);
+    }
+    else if (raw < minChannelValue)
+    {
+        return 0;
+    } else
+    {
+        return 100;
+    }
+}
+
+unsigned PPMReader::latestValidPercentage(byte channel, unsigned defaultValue){
+    unsigned raw = latestValidPercentage(channel, defaultValue);
+
+    if(raw >= minChannelValue && raw <= maxChannelValue)
+    {
+        return map(raw, minChannelValue, maxChannelValue, 0, 100);
+    }
+    else if (raw < minChannelValue)
+    {
+        return 0;
+    } else
+    {
+        return 100;
+    }
+}
+
+
 unsigned PPMReader::latestValidChannelValue(byte channel, unsigned defaultValue) {
     // Check for channel's validity and return the latest valid channel value or defaultValue.
     unsigned value = defaultValue;

src/PPMReader.h

@@ -60,7 +60,6 @@ class PPMReader {
     volatile unsigned long microsAtLastPulse = 0;
 
     // Pointer to PPMReader object used by ISR. Replace by an array if multiple PPM reader instances are needed
-    static PPMReader *ppm;
 
     public:
 
@@ -70,17 +69,30 @@ class PPMReader {
     // Returns the latest raw (not necessarily valid) value for the channel (starting from 1)
     unsigned rawChannelValue(byte channel);
 
+    unsigned percentageChannelValue(byte channel);
+    unsigned latestValidPercentage(byte channel, unsigned defaultValue);
     // Returns the latest received value that was considered valid for the channel (starting from 1)
     // Returns defaultValue if the channel hasn't received any valid values yet, or the PPM signal was absent for more than failsafeTimeout
     unsigned latestValidChannelValue(byte channel, unsigned defaultValue);
 
+
+
+#if defined(ESP32)
+    public:
+    static PPMReader *ppm;
+    static void PPM_ISR(void);
+    void begin();
+#else
+    private:
+    static PPMReader *ppm;
+    static void PPM_ISR(void);
+#endif
     private:
 
     // An interrupt service routine for handling the interrupts activated by PPM pulses
     void handleInterrupt(void);
 
     // Interrupt service routine function compatible with attachInterrupt. Add more funcitons if multiple PPM reader instances are needed
-    static void PPM_ISR(void);
 
 };