Improving mark function

README.md

@@ -162,13 +162,11 @@ We are open to suggestions for adding support to new boards, however we highly r
 # Timer and pin usage
 The receiver sample interval is generated by a timer. On many boards this must be a hardware timer, on some a software timer is available and used.<br/>
 Every pin can be used for receiving.<br/>
-The send PWM signal is by default generated by software. **Therefore every pin can be used for sending**.
+The send PWM signal is by default generated by software. **Therefore every pin can be used for sending**. The PWM pulse length is guaranteed to be constant by using `delayMicroseconds()`. Take care not to generate interrupts during sending with software generated PWM, otherwise you will get jitter in the generated PWM. E.g. wait for a former `Serial.print()` statement to be finished by `Serial.flush()`. Since the Arduino `micros()` function has a resolution of 4 us at 16 MHz, we always see a small jitter in the signal, which seems to be OK for the receivers.
 
-| Software generated PWM showing discontinuities in the Arduino core micros() function | Zoom into the discontinuity. The space is once too short but compensated at the next one |
+| Software generated PWM showing small jitter because of the limited resolution of 4 us of the Arduino core `micros()` function for an ATmega328 | Detail (ATmega328 generated) showing 33% Duty cycle |
 |-|-|
-| ![Software PWM](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/pictures/IR_PWM_by_software.png)                                                              | ![Software PWM detail](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/pictures/IR_PWM_by_software_zoom.png) |
-| Software generated PWM (ATmega328) with 33% Duty cycle |   |
-| ![Software PWM detail](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/pictures/IR_PWM_by_software_detail.png) |   |
+| ![Software PWM](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/pictures/IR_PWM_by_software_jitter.png)                                                              | ![Software PWM detail](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/pictures/IR_PWM_by_software_detail.png) |
 
 ## Hardware-PWM signal generation for sending
 If you define `SEND_PWM_BY_TIMER`, the send PWM signal is generated by a hardware timer. The same timer as for the receiver is used.

changelog.md

@@ -17,6 +17,7 @@ The latest version may not be released!
 - Added ATtiny88 support.
 - Use LED_BUILTIN instead of FEEDBACK_LED FeedbackLEDPin is 0.
 - Use F_CPU instead of SYSCLOCK.
+- Removed SENDPIN_ON and SENDPIN_OFF macros.
 
 ## 3.0.2
 - Bug fix for USE_OLD_DECODE.

examples/SendDemo/SendDemo.ino

@@ -58,7 +58,7 @@ void setup() {
     Serial.print(F("Ready to send IR signals at pin "));
     Serial.println(IR_SEND_PIN);
 
-    #if defined(USE_SOFT_SEND_PWM) && !defined(ESP32) // for esp32 we use PWM generation by hw_timer_t for each pin
+#if defined(USE_SOFT_SEND_PWM) && !defined(ESP32) // for esp32 we use PWM generation by hw_timer_t for each pin
     /*
      * Print internal signal generation info
      */
@@ -100,10 +100,12 @@ void loop() {
     Serial.flush();
 
     Serial.println(F("Send NEC with 8 bit address"));
+    Serial.flush();
     IrSender.sendNEC(sAddress & 0xFF, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND); // delay must be greater than 5 ms (RECORD_GAP_MICROS), otherwise the receiver sees it as one long signal
 
     Serial.println(F("Send NEC with 16 bit address"));
+    Serial.flush();
     IrSender.sendNEC(sAddress, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND);
 
@@ -113,6 +115,7 @@ void loop() {
          * Send constant values only once in this demo
          */
         Serial.println(F("Sending NEC Pronto data with 8 bit address 0x80 and command 0x45 and no repeats"));
+        Serial.flush();
         IrSender.sendPronto(F("0000 006D 0022 0000 015E 00AB " /* Pronto header + start bit */
                 "0017 0015 0017 0015 0017 0017 0015 0017 0017 0015 0017 0015 0017 0015 0017 003F " /* Lower address byte */
                 "0017 003F 0017 003E 0017 003F 0015 003F 0017 003E 0017 003F 0017 003E 0017 0015 " /* Upper address byte (inverted at 8 bit mode) */
@@ -127,6 +130,7 @@ void loop() {
         Serial.println(
                 F(
                         "Send NEC with 16 bit address 0x0102 and command 0x34 with NECRaw(0xCC340102) which results in a parity error, since 34 == ~CB and not C0"));
+        Serial.flush();
         IrSender.sendNECRaw(0xC0340102, sRepeats);
         delay(DELAY_AFTER_SEND);
 
@@ -136,52 +140,64 @@ void loop() {
          * Example:
          * 0xCB340102 byte reverse -> 0x020134CB bit reverse-> 40802CD3
          */
+        Serial.flush();
         Serial.println(F("Send NEC with 16 bit address 0x0102 and command 0x34 with old 32 bit format MSB first"));
         IrSender.sendNECMSB(0x40802CD3, 32, false);
         delay(DELAY_AFTER_SEND);
     }
 
     Serial.println(F("Send Apple"));
+    Serial.flush();
     IrSender.sendApple(sAddress & 0xFF, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Panasonic"));
+    Serial.flush();
     IrSender.sendPanasonic(sAddress & 0xFFF, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Kaseikyo with 0x4711 as Vendor ID"));
+    Serial.flush();
     IrSender.sendKaseikyo(sAddress & 0xFFF, sCommand, sRepeats, 0x4711);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Denon"));
+    Serial.flush();
     IrSender.sendDenon(sAddress & 0x1F, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Denon/Sharp variant"));
+    Serial.flush();
     IrSender.sendSharp(sAddress & 0x1F, sCommand, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Sony/SIRCS with 7 command and 5 address bits"));
+    Serial.flush();
     IrSender.sendSony(sAddress & 0x1F, sCommand & 0x7F, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Sony/SIRCS with 7 command and 8 address bits"));
+    Serial.flush();
     IrSender.sendSony(sAddress & 0xFF, sCommand, sRepeats, SIRCS_15_PROTOCOL);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send Sony/SIRCS with 7 command and 13 address bits"));
+    Serial.flush();
     IrSender.sendSony(sAddress & 0x1FFF, sCommand & 0x7F, sRepeats, SIRCS_20_PROTOCOL);
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send RC5"));
+    Serial.flush();
     IrSender.sendRC5(sAddress & 0x1F, sCommand & 0x3F, sRepeats, true); // 5 address, 6 command bits
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send RC5X with 7.th MSB of command set"));
+    Serial.flush();
     IrSender.sendRC5(sAddress & 0x1F, (sCommand & 0x3F) + 0x40, sRepeats, true); // 5 address, 7 command bits
     delay(DELAY_AFTER_SEND);
 
     Serial.println(F("Send RC6"));
+    Serial.flush();
     IrSender.sendRC6(sAddress, sCommand, sRepeats, true);
     delay(DELAY_AFTER_SEND);
 
@@ -204,17 +220,20 @@ void loop() {
     IRSendData.protocol = JVC; // switch protocol
     Serial.print(F("Send "));
     Serial.println(getProtocolString(IRSendData.protocol));
+    Serial.flush();
     IrSender.write(&IRSendData, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     IRSendData.protocol = LG;
     Serial.print(F("Send "));
     Serial.println(getProtocolString(IRSendData.protocol));
+    Serial.flush();
     IrSender.write(&IRSendData, sRepeats);
     delay(DELAY_AFTER_SEND);
 
     IRSendData.protocol = BOSEWAVE;
     Serial.println(F("Send Bosewave with no address and 8 command bits"));
+    Serial.flush();
     IrSender.write(&IRSendData, sRepeats);
     delay(DELAY_AFTER_SEND);
 
@@ -222,6 +241,7 @@ void loop() {
      * LEGO is difficult to receive because of its short marks and spaces
      */
     Serial.println(F("Send Lego with 2 channel and with 4 command bits"));
+    Serial.flush();
     IrSender.sendLegoPowerFunctions(sAddress, sCommand, LEGO_MODE_COMBO, true);
     delay(DELAY_AFTER_SEND);
 
@@ -248,6 +268,5 @@ void loop() {
         sRepeats = 4;
     }
 
-
     delay(DELAY_AFTER_LOOP); // additional delay at the end of each loop
 }

examples/SendLGAirConditionerDemo/SendLGAirConditionerDemo.ino

@@ -64,6 +64,7 @@ void ACSendCode(uint16_t aCommand) {
     Serial.print(aCommand, HEX);
     Serial.print(F(" | "));
     Serial.println(aCommand, BIN);
+    Serial.flush();
     IrSender.sendLG((uint8_t) 0x88, aCommand, 0);
 }
 

examples/SendRawDemo/SendRawDemo.ino

@@ -91,6 +91,7 @@ void loop() {
      * The values are NOT multiple of 50, but are taken from the NEC timing definitions
      */
     Serial.println(F("Send NEC 8 bit address 0xFB04, 0x08 with exact timing (16 bit array format)"));
+    Serial.flush();
 
     const uint16_t irSignal[] = { 9000, 4500, 560, 560, 560, 560, 560, 1690, 560, 560, 560, 560, 560, 560, 560, 560, 560, 560, 560,
             1690, 560, 1690, 560, 560, 560, 1690, 560, 1690, 560, 1690, 560, 1690, 560, 1690, 560, 560, 560, 560, 560, 560, 560,
@@ -106,11 +107,13 @@ void loop() {
      * Note the approach used to automatically calculate the size of the array.
      */
     Serial.println(F("Send NEC 16 bit address 0xFB0C, 0x18 with (50 us) tick resolution timing (8 bit array format) "));
+    Serial.flush();
     IrSender.sendRaw_P(irSignalP, sizeof(irSignalP) / sizeof(irSignalP[0]), NEC_KHZ);
 
     delay(1000); // delay must be greater than 5 ms (RECORD_GAP_MICROS), otherwise the receiver sees it as one long signal
 
     Serial.println(F("Send NEC 16 bit address 0x0102, 8 bit data 0x34 with generated timing"));
+    Serial.flush();
     IrSender.sendNEC(0x0102, 0x34, true, 0);
 
     delay(3000);

examples/SimpleSender/SimpleSender.ino

@@ -64,6 +64,7 @@ void loop() {
     Serial.println();
 
     Serial.println(F("Send NEC with 16 bit address"));
+    Serial.flush();
 
     // Results for the first loop to: Protocol=NEC Address=0x102 Command=0x34 Raw-Data=0xCB340102 (32 bits)
     IrSender.sendNEC(sAddress, sCommand, sRepeats);

src/IRSend.cpp.h

@@ -31,6 +31,7 @@
  */
 
 #include "IRremoteInt.h"
+//#include "digitalWriteFast.h"
 
 __attribute((error("Version > 3.0.1"))) void UsageError(const char *details);
 
@@ -360,36 +361,27 @@ void IRsend::mark(unsigned int aMarkMicros) {
 #if defined(USE_SOFT_SEND_PWM) && !defined(ESP32) // for esp32 we use PWM generation by hw_timer_t for each pin
     unsigned long start = micros();
     unsigned long nextPeriodEnding = start;
-    while (micros() - start < aMarkMicros) {
+    unsigned long tMicros;
+    do {
+//        digitalToggleFast(IR_TIMING_TEST_PIN);
         // Output the PWM pulse
         noInterrupts(); // do not let interrupts extend the short on period
-#  ifdef SENDPIN_ON
-        SENDPIN_ON(sendPin);
-#  else
-        digitalWrite(sendPin, HIGH);
-#  endif
+        digitalWrite(sendPin, HIGH); // 4.3 us from do{ to pin setting
         delayMicroseconds(periodOnTimeMicros); // this is normally implemented by a blocking wait
 
         // Output the PWM pause
-#  ifdef SENDPIN_OFF
-        SENDPIN_OFF(sendPin);
-#  else
         digitalWrite(sendPin, LOW);
-#  endif
         interrupts(); // Enable interrupts -to keep micros correct- for the longer off period 3.4 us until receive ISR is active (for 7 us + pop's)
         nextPeriodEnding += periodTimeMicros;
-        while (micros() < nextPeriodEnding){
-            ;
-        }
-    }
+        do {
+            tMicros = micros(); // we have only 4 us resolution for and AVR @16MHz
+//            digitalToggleFast(IR_TIMING_TEST_PIN); // 3.0 us per call @16MHz
+        } while (tMicros < nextPeriodEnding);  // 3.4 us @16MHz
+    } while (tMicros - start < aMarkMicros);
 
 #else
 #  if defined(USE_NO_SEND_PWM)
-#  ifdef SENDPIN_OFF
-    SENDPIN_OFF(sendPin);
-#  else
     digitalWrite(sendPin, LOW); // Set output to active low.
-#  endif
 
 #  else
     TIMER_ENABLE_SEND_PWM; // Enable pin 3 PWM output
@@ -408,11 +400,7 @@ void IRsend::mark(unsigned int aMarkMicros) {
  */
 void IRsend::ledOff() {
 #if defined(USE_SOFT_SEND_PWM) && !defined(ESP32) // for esp32 we use PWM generation by hw_timer_t for each pin
-#  ifdef SENDPIN_OFF
-    SENDPIN_OFF(sendPin);
-#  else
     digitalWrite(sendPin, LOW);
-#  endif
 #elif defined(USE_NO_SEND_PWM)
     digitalWrite(sendPin, HIGH); // Set output to inactive high.
 #else

src/IRremote.h

@@ -164,7 +164,7 @@
 
 /**
  * If USE_SOFT_SEND_PWM, this amount is subtracted from the on-time of the pulses.
- * It should be the time used for SENDPIN_OFF(sendPin) and the call to delayMicros()
+ * It should be the time used for digitalWrite(sendPin, LOW) and the call to delayMicros()
  * Measured value for Nano @16MHz is around 3000, for Bluepill @72MHz is around 700, for Zero 3600
  */
 #ifndef PULSE_CORRECTION_NANOS

src/IRremoteInt.h

@@ -474,7 +474,7 @@ public:
     uint8_t sendPin;
 
     unsigned int periodTimeMicros;
-    unsigned int periodOnTimeMicros;
+    unsigned int periodOnTimeMicros; // compensated with PULSE_CORRECTION_NANOS for duration of digitalWrite.
 
     void customDelayMicroseconds(unsigned long aMicroseconds);
 };