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This library enables you to use 1 Hardware Timer on SAMD21/SAMD51-based board, such as Nano-33-IoT, Seeeduino XIAO, Adafruit Itsy-Bitsy M4, etc. to control up to 16 or more servo motors.

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SAMD_ISR_Servo Library

arduino-library-badge GitHub release GitHub contributions welcome GitHub issues

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Table of Contents



Important Change from v1.1.0

Please have a look at HOWTO Fix Multiple Definitions Linker Error



Why do we need this SAMD_ISR_Servo library

Features

Imagine you have a system with a mission-critical function controlling a robot arm or doing something much more important. You normally use a software timer to poll, or even place the function in loop(). But what if another function is blocking the loop() or setup().

So your function might not be executed, and the result would be disastrous.

You'd prefer to have your function called, no matter what happening with other functions (busy loop, bug, etc.).

The correct choice is to use a Hardware Timer with Interrupt to call your function.

These hardware timers, using interrupt, still work even if other functions are blocking. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software timers using millis() or micros(). That's necessary if you need to measure some data requiring better accuracy.

Functions using normal software timers, relying on loop() and calling millis(), won't work if the loop() or setup() is blocked by certain operation. For example, certain function is blocking while it's connecting to WiFi or some services.

This library enables you to use 1 Hardware Timer on an SAMD-based board to control up to 16 independent servo motors.

Important Notes about using ISR

  1. Inside the attached function, delay() won’t work and the value returned by millis() will not increment. Serial data received while in the function may be lost. You should declare as volatile any variables that you modify within the attached function.

  2. Typically global variables are used to pass data between an ISR and the main program. To make sure variables shared between an ISR and the main program are updated correctly, declare them as volatile.

  3. Avoid using Serial.print()-related functions inside ISR. Just for temporary debug purpose, but even this also can crash the system any time. Beware.

  4. Your functions are now part of ISR (Interrupt Service Routine), and must be lean / mean, and follow certain rules. More to read on:

HOWTO Attach Interrupt

Currently supported Boards

  • Arduino SAMD21 (ZERO, MKR, NANO_33_IOT, etc.).
  • Adafruit SAM21 (Itsy-Bitsy M0, Metro M0, Feather M0, Gemma M0, etc.).
  • Adafruit SAM51 (Itsy-Bitsy M4, Metro M4, Grand Central M4, Feather M4 Express, etc.).
  • Seeeduino SAMD21/SAMD51 boards (SEEED_WIO_TERMINAL, SEEED_FEMTO_M0, SEEED_XIAO_M0, Wio_Lite_MG126, WIO_GPS_BOARD, SEEEDUINO_ZERO, SEEEDUINO_LORAWAN, SEEED_GROVE_UI_WIRELESS, etc.)
  • Sparkfun SAMD21 boards such as SparkFun_RedBoard_Turbo, SparkFun_Qwiic_Micro, etc.
  • Sparkfun SAMD51 boards such as SparkFun_SAMD51_Thing_Plus, SparkFun_SAMD51_MicroMod, etc.


Prerequisites

  1. Arduino IDE 1.8.19+ for Arduino. GitHub release
  2. Arduino SAMD core 1.8.13+ for SAMD ARM Cortex-M0+ boards. GitHub release
  3. Adafruit SAMD core 1.7.11+ for SAMD ARM Cortex-M0+ and M4 boards (Nano 33 IoT, etc.). GitHub release
  4. Seeeduino SAMD core 1.8.3+ for SAMD21/SAMD51 boards (XIAO M0, Wio Terminal, etc.). Latest release
  5. Sparkfun SAMD core 1.8.1+ for SAMD21/SAMD51 boards (SparkFun_RedBoard_Turbo, SparkFun_SAMD51_Thing_Plus, etc.).

Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for SAMD_ISR_Servo, then select / install the latest version. You can also use this link arduino-library-badge for more detailed instructions.

Manual Install

Another way to install is to:

  1. Navigate to SAMD_ISR_Servo page.
  2. Download the latest release SAMD_ISR_Servo-main.zip.
  3. Extract the zip file to SAMD_ISR_Servo-main directory
  4. Copy whole SAMD_ISR_Servo-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

  1. Install VS Code
  2. Install PlatformIO
  3. Install SAMD_ISR_Servo library by using Library Manager. Search for SAMD_ISR_Servo in Platform.io Author's Libraries
  4. Use included platformio.ini file from examples to ensure that all dependent libraries will installed automatically. Please visit documentation for the other options and examples at Project Configuration File


Packages' Patches

1. For Arduino SAMD boards

To be able to compile without error and automatically detect and display BOARD_NAME on Arduino SAMD (Nano-33-IoT, etc) boards, you have to copy the whole Arduino SAMD Packages_Patches directory into Arduino SAMD directory (~/.arduino15/packages/arduino/hardware/samd/1.8.13).

For core version v1.8.10+

Supposing the Arduino SAMD version is 1.8.13. Now only one file must be copied into the directory:

  • ~/.arduino15/packages/arduino/hardware/samd/1.8.13/platform.txt

Whenever a new version is installed, remember to copy this files into the new version directory. For example, new version is x.yy.zz

This file must be copied into the directory:

  • ~/.arduino15/packages/arduino/hardware/samd/x.yy.zz/platform.txt

For core version v1.8.9-

Supposing the Arduino SAMD version is 1.8.9. These files must be copied into the directory:

  • ~/.arduino15/packages/arduino/hardware/samd/1.8.9/platform.txt
  • ~/.arduino15/packages/arduino/hardware/samd/1.8.9/cores/arduino/Arduino.h

Whenever a new version is installed, remember to copy these files into the new version directory. For example, new version is x.yy.z

These files must be copied into the directory:

  • ~/.arduino15/packages/arduino/hardware/samd/x.yy.z/platform.txt
  • ~/.arduino15/packages/arduino/hardware/samd/x.yy.z/cores/arduino/Arduino.h

This is mandatory to fix the notorious Arduino SAMD compiler error. See Improve Arduino compatibility with the STL (min and max macro)

 ...\arm-none-eabi\include\c++\7.2.1\bits\stl_algobase.h:243:56: error: macro "min" passed 3 arguments, but takes just 2
     min(const _Tp& __a, const _Tp& __b, _Compare __comp)

Whenever the above-mentioned compiler error issue is fixed with the new Arduino SAMD release, you don't need to copy the Arduino.h file anymore.

2. For Adafruit SAMD boards

To be able to compile without error and automatically detect and display BOARD_NAME on Adafruit SAMD (Itsy-Bitsy M4, etc) boards, you have to copy the files in Adafruit SAMD Packages_Patches into Adafruit samd directory (~/.arduino15/packages/adafruit/hardware/samd/1.7.11).

Supposing the Adafruit SAMD core version is 1.7.11. This file must be copied into the directory:

  • ~/.arduino15/packages/adafruit/hardware/samd/1.7.11/platform.txt
  • ~/.arduino15/packages/adafruit/hardware/samd/1.7.11/cores/arduino/Print.h
  • ~/.arduino15/packages/adafruit/hardware/samd/1.7.11/cores/arduino/Print.cpp

Whenever a new version is installed, remember to copy this file into the new version directory. For example, new version is x.yy.zz This file must be copied into the directory:

  • ~/.arduino15/packages/adafruit/hardware/samd/x.yy.zz/platform.txt
  • ~/.arduino15/packages/adafruit/hardware/samd/x.yy.zz/cores/arduino/Print.h
  • ~/.arduino15/packages/adafruit/hardware/samd/x.yy.zz/cores/arduino/Print.cpp

3. For Seeeduino SAMD boards

To be able to compile without error and automatically detect and display BOARD_NAME on Seeeduino SAMD (XIAO M0, Wio Terminal, etc) boards, you have to copy the files in Seeeduino SAMD Packages_Patches into Seeeduino samd directory (~/.arduino15/packages/Seeeduino/hardware/samd/1.8.3).

Supposing the Seeeduino SAMD core version is 1.8.3. This file must be copied into the directory:

  • ~/.arduino15/packages/Seeeduino/hardware/samd/1.8.3/platform.txt
  • ~/.arduino15/packages/Seeeduino/hardware/samd/1.8.3/cores/arduino/Arduino.h
  • ~/.arduino15/packages/Seeeduino/hardware/samd/1.8.3/cores/arduino/Print.h
  • ~/.arduino15/packages/Seeeduino/hardware/samd/1.8.3/cores/arduino/Print.cpp

Whenever a new version is installed, remember to copy this file into the new version directory. For example, new version is x.yy.zz This file must be copied into the directory:

  • ~/.arduino15/packages/Seeeduino/hardware/samd/x.yy.zz/platform.txt
  • ~/.arduino15/packages/Seeeduino/hardware/samd/x.yy.zz/cores/arduino/Arduino.h
  • ~/.arduino15/packages/Seeeduino/hardware/samd/x.yy.zz/cores/arduino/Print.h
  • ~/.arduino15/packages/Seeeduino/hardware/samd/x.yy.zz/cores/arduino/Print.cpp

4. For SparkFun SAMD boards

To be able to compile without error and automatically detect and display BOARD_NAME on SparkFun SAMD (XIAO SparkFun_RedBoard_Turbo, SparkFun_SAMD51_Thing_Plus, etc) boards, you have to copy the file SparkFun SAMD Packages_Patches into SparkFun samd directory (~/.arduino15/packages/SparkFun/hardware/samd/1.8.3).

Supposing the SparkFun SAMD core version is 1.8.3. This file must be copied into the directory:

  • ~/.arduino15/packages/SparkFun/hardware/samd/1.8.3/cores/arduino/Print.h
  • ~/.arduino15/packages/SparkFun/hardware/samd/1.8.3/cores/arduino/Print.cpp
  • ~/.arduino15/packages/SparkFun/hardware/samd/1.8.3/cores/arduino51/Print.h
  • ~/.arduino15/packages/SparkFun/hardware/samd/1.8.3/cores/arduino51/Print.cpp

Whenever a new version is installed, remember to copy this file into the new version directory. For example, new version is x.yy.zz This file must be copied into the directory:

  • ~/.arduino15/packages/SparkFun/hardware/samd/x.yy.zz/cores/arduino/Print.h
  • ~/.arduino15/packages/SparkFun/hardware/samd/x.yy.zz/cores/arduino/Print.cpp
  • ~/.arduino15/packages/SparkFun/hardware/samd/x.yy.zz/cores/arduino51/Print.h
  • ~/.arduino15/packages/SparkFun/hardware/samd/x.yy.zz/cores/arduino51/Print.cpp


HOWTO Fix Multiple Definitions Linker Error

The current library implementation, using xyz-Impl.h instead of standard xyz.cpp, possibly creates certain Multiple Definitions Linker error in certain use cases.

You can include this .hpp file

// Can be included as many times as necessary, without `Multiple Definitions` Linker Error
#include "SAMD_ISR_Servo.hpp"     //https://github.com/khoih-prog/SAMD_ISR_Servo

in many files. But be sure to use the following .h file in just 1 .h, .cpp or .ino file, which must not be included in any other file, to avoid Multiple Definitions Linker Error

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "SAMD_ISR_Servo.h"           //https://github.com/khoih-prog/SAMD_ISR_Servo

Check the new multiFileProject example for a HOWTO demo.

Have a look at the discussion in Different behaviour using the src_cpp or src_h lib #80



What special in this SAMD_ISR_Servo library

Now these new 16 ISR-based Servo controllers just use one SAMD Hardware Timer. The number 16 is just arbitrarily chosen, and depending on application, you can increase that number to 32, 48, etc. without problem.

The accuracy is nearly perfect compared to software timers. The most important feature is they're ISR-based timers

Therefore, their executions are not blocked by bad-behaving functions / tasks. This important feature is absolutely necessary for mission-critical tasks.

The SAMD_MultipleServos example, which controls 6 servos independently, will demonstrate the nearly perfect accuracy.

Being ISR-based servo controllers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet and Blynk services.

This non-being-blocked important feature is absolutely necessary for mission-critical tasks.



HOWTO Usage

How to use:

#if !( defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_SAMD_MKR1000) || defined(ARDUINO_SAMD_MKRWIFI1010) \
|| defined(ARDUINO_SAMD_NANO_33_IOT) || defined(ARDUINO_SAMD_MKRFox1200) || defined(ARDUINO_SAMD_MKRWAN1300) || defined(ARDUINO_SAMD_MKRWAN1310) \
|| defined(ARDUINO_SAMD_MKRGSM1400) || defined(ARDUINO_SAMD_MKRNB1500) || defined(ARDUINO_SAMD_MKRVIDOR4000) \
|| defined(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
|| defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__) \
|| defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
|| defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
|| defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
#error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
#endif
#define ISR_SERVO_DEBUG 1
// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "SAMD_ISR_Servo.h"
// TIMER_TC3 for SAMD51, TIMER_TC3/TIMER_TCC for SAMD21
#define USING_SAMD_TIMER TIMER_TC3
// Published values for SG90 servos; adjust if needed
#define MIN_MICROS 800
#define MAX_MICROS 2450
#define SERVO_PIN_1 A0
#define SERVO_PIN_2 A1
#define SERVO_PIN_3 A2
#define SERVO_PIN_4 A3
#define SERVO_PIN_5 A4
#define SERVO_PIN_6 A5
typedef struct
{
int servoIndex;
uint8_t servoPin;
} ISR_servo_t;
#define NUM_SERVOS 6
ISR_servo_t ISR_servo[] =
{
{ -1, SERVO_PIN_1 }, { -1, SERVO_PIN_2 }, { -1, SERVO_PIN_3 }, { -1, SERVO_PIN_4 }, { -1, SERVO_PIN_5 }, { -1, SERVO_PIN_6 }
};
void setup()
{
for (int index = 0; index < NUM_SERVOS; index++)
{
pinMode(ISR_servo[index].servoPin, OUTPUT);
digitalWrite(ISR_servo[index].servoPin, LOW);
}
Serial.begin(115200);
while (!Serial);
delay(200);
Serial.print(F("\nStarting SAMD_MultipleRandomServos on "));
Serial.println(BOARD_NAME);
Serial.println(SAMD_ISR_SERVO_VERSION);
// SAMD51 always uses TIMER_TC3
SAMD_ISR_Servos.useTimer(USING_SAMD_TIMER);
for (int index = 0; index < NUM_SERVOS; index++)
{
ISR_servo[index].servoIndex = SAMD_ISR_Servos.setupServo(ISR_servo[index].servoPin, MIN_MICROS, MAX_MICROS);
if (ISR_servo[index].servoIndex != -1)
{
Serial.print(F("Setup OK Servo index = "));
Serial.println(ISR_servo[index].servoIndex);
}
else
{
Serial.print(F("Setup Failed Servo index = "));
Serial.println(ISR_servo[index].servoIndex);
}
}
SAMD_ISR_Servos.setReadyToRun();
}
void printServoInfo(int indexServo)
{
Serial.print(F("Servos idx = "));
Serial.print(indexServo);
Serial.print(F(", act. pos. (deg) = "));
Serial.print(SAMD_ISR_Servos.getPosition(ISR_servo[indexServo].servoIndex) );
Serial.print(F(", pulseWidth (us) = "));
Serial.println(SAMD_ISR_Servos.getPulseWidth(ISR_servo[indexServo].servoIndex));
}
void loop()
{
int position; // position in degrees
position = 0;
Serial.println(F("Servos @ 0 degree"));
for (int index = 0; index < NUM_SERVOS; index++)
{
SAMD_ISR_Servos.setPosition(ISR_servo[index].servoIndex, position );
printServoInfo(index);
}
// waits 5s between test
delay(5000);
position = 90;
Serial.println(F("Servos @ 90 degree"));
for (int index = 0; index < NUM_SERVOS; index++)
{
SAMD_ISR_Servos.setPosition(ISR_servo[index].servoIndex, position );
printServoInfo(index);
}
// waits 5s between test
delay(5000);
position = 180;
Serial.println(F("Servos @ 180 degree"));
for (int index = 0; index < NUM_SERVOS; index++)
{
SAMD_ISR_Servos.setPosition(ISR_servo[index].servoIndex, position );
printServoInfo(index);
}
// waits 5s between test
delay(5000);
Serial.println(F("Servos sweeps from 0-180 degress"));
for (position = 0; position <= 180; position += 5)
{
// goes from 0 degrees to 180 degrees
// in steps of 1 degree
for (int index = 0; index < NUM_SERVOS; index++)
{
SAMD_ISR_Servos.setPosition(ISR_servo[index].servoIndex, position );
}
// waits 0.1s for the servo to reach the position
delay(100);
}
// waits 5s between test
delay(5000);
}



Examples:

  1. SAMD_MultipleRandomServos
  2. SAMD_MultipleServos
  3. multiFileProject. New

#if !( defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_SAMD_MKR1000) || defined(ARDUINO_SAMD_MKRWIFI1010) \
|| defined(ARDUINO_SAMD_NANO_33_IOT) || defined(ARDUINO_SAMD_MKRFox1200) || defined(ARDUINO_SAMD_MKRWAN1300) || defined(ARDUINO_SAMD_MKRWAN1310) \
|| defined(ARDUINO_SAMD_MKRGSM1400) || defined(ARDUINO_SAMD_MKRNB1500) || defined(ARDUINO_SAMD_MKRVIDOR4000) \
|| defined(ARDUINO_SAMD_CIRCUITPLAYGROUND_EXPRESS) || defined(__SAMD51__) || defined(__SAMD51J20A__) \
|| defined(__SAMD51J19A__) || defined(__SAMD51G19A__) || defined(__SAMD51P19A__) \
|| defined(__SAMD21E15A__) || defined(__SAMD21E16A__) || defined(__SAMD21E17A__) || defined(__SAMD21E18A__) \
|| defined(__SAMD21G15A__) || defined(__SAMD21G16A__) || defined(__SAMD21G17A__) || defined(__SAMD21G18A__) \
|| defined(__SAMD21J15A__) || defined(__SAMD21J16A__) || defined(__SAMD21J17A__) || defined(__SAMD21J18A__) )
#error This code is designed to run on SAMD21/SAMD51 platform! Please check your Tools->Board setting.
#endif
#define ISR_SERVO_DEBUG 2
// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "SAMD_ISR_Servo.h"
// TIMER_TC3 for SAMD51, TIMER_TC3/TIMER_TCC for SAMD21
#define USING_SAMD_TIMER TIMER_TC3
// Published values for SG90 servos; adjust if needed
#define MIN_MICROS 800
#define MAX_MICROS 2450
#define SERVO_PIN_1 A0
#define SERVO_PIN_2 A1
#define SERVO_PIN_3 A2
#define SERVO_PIN_4 A3
#define SERVO_PIN_5 A4
#define SERVO_PIN_6 A5
typedef struct
{
int servoIndex;
uint8_t servoPin;
} ISR_servo_t;
#define NUM_SERVOS 6
ISR_servo_t ISR_servo[] =
{
{ -1, SERVO_PIN_1 }, { -1, SERVO_PIN_2 }, { -1, SERVO_PIN_3 }, { -1, SERVO_PIN_4 }, { -1, SERVO_PIN_5 }, { -1, SERVO_PIN_6 }
};
void setup()
{
for (int index = 0; index < NUM_SERVOS; index++)
{
pinMode(ISR_servo[index].servoPin, OUTPUT);
digitalWrite(ISR_servo[index].servoPin, LOW);
}
Serial.begin(115200);
while (!Serial);
delay(200);
Serial.print(F("\nStarting SAMD_MultipleServos on "));
Serial.println(BOARD_NAME);
Serial.println(SAMD_ISR_SERVO_VERSION);
// SAMD51 always uses TIMER_TC3
SAMD_ISR_Servos.useTimer(USING_SAMD_TIMER);
for (int index = 0; index < NUM_SERVOS; index++)
{
ISR_servo[index].servoIndex = SAMD_ISR_Servos.setupServo(ISR_servo[index].servoPin, MIN_MICROS, MAX_MICROS);
if (ISR_servo[index].servoIndex != -1)
{
Serial.print(F("Setup OK, Servo index = "));
Serial.println(ISR_servo[index].servoIndex);
}
else
{
Serial.print(F("Setup Failed, Servo index = "));
Serial.println(ISR_servo[index].servoIndex);
}
}
SAMD_ISR_Servos.setReadyToRun();
}
void loop()
{
int position; // position in degrees
for (position = 0; position <= 180; position += 10)
{
// goes from 0 degrees to 180 degrees
// in steps of 10 degree
for (int index = 0; index < NUM_SERVOS; index++)
{
SAMD_ISR_Servos.setPosition(ISR_servo[index].servoIndex, position);
}
// waits 1s for the servo to reach the position
delay(1000);
}
delay(5000);
}



Debug Terminal Output Samples

1. SAMD_MultipleRandomServos on Adafruit SAMD51 ITSYBITSY_M4

Starting SAMD_MultipleRandomServos on ITSYBITSY_M4
SAMD_ISR_Servo v1.1.0
Setup OK, Servo index = 0
Setup OK, Servo index = 1
Setup OK, Servo index = 2
Setup OK, Servo index = 3
Setup OK, Servo index = 4
Setup OK, Servo index = 5
[ISR_SERVO] _period = 10 , frequency = 100000.00
[ISR_SERVO] SAMDFastTimerInterrupt: F_CPU (MHz) = 120 , TIMER_HZ = 48
[ISR_SERVO] TC_Timer::startTimer _Timer = 0x 4101C000
[ISR_SERVO] TC_Timer::startTimer TC3 = 0x 4101C000
[ISR_SERVO] SAMD51 TC3 period = 10 , _prescaler = 1
[ISR_SERVO] _compareValue = 479
[ISR_SERVO] Starting  ITimer OK
Servos @ 0 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos @ 90 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos @ 180 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos sweeps from 0-180 degrees
Servos @ 0 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
800

2. SAMD_MultipleRandomServos on Arduino SAMD21 SAMD_NANO_33_IOT

Starting SAMD_MultipleRandomServos on SAMD_NANO_33_IOT
SAMD_ISR_Servo v1.1.0
Setup OK Servo index = 0
Setup OK Servo index = 1
Setup OK Servo index = 2
Setup OK Servo index = 3
Setup OK Servo index = 4
Setup OK Servo index = 5
[ISR_SERVO] _period = 20 , frequency = 50000.00
[ISR_SERVO] SAMDFastTimerInterrupt: F_CPU (MHz) = 48 , TIMER_HZ = 48
[ISR_SERVO] TC_Timer::startTimer _Timer = 0x 42002C00
[ISR_SERVO] TC_Timer::startTimer TC3 = 0x 42002C00
[ISR_SERVO] SAMD21 TC3 period = 20 , _prescaler = 1
[ISR_SERVO] _compareValue = 959
[ISR_SERVO] Starting  ITimer OK
Servos @ 0 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 40 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 40 , pos = 0
800
Servos @ 90 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 81 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 81 , pos = 90
1620
Servos @ 180 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos idx = 3, act. pos. (deg) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 3
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos idx = 4, act. pos. (deg) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 4
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos idx = 5, act. pos. (deg) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 122 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 5
[ISR_SERVO] cnt = 122 , pos = 180
2440
Servos sweeps from 0-180 degrees
Servos @ 0 degree

3. SAMD_MultipleRandomServos on Seeeduino SAMD21 SEEED_XIAO_M0

Starting SAMD_MultipleRandomServos on SEEED_XIAO_M0
SAMD_ISR_Servo v1.1.0
[ISR_SERVO] _period = 20 , frequency = 50000.00
[ISR_SERVO] SAMDFastTimerInterrupt: F_CPU (MHz) = 48 , TIMER_HZ = 48
[ISR_SERVO] TC_Timer::startTimer _Timer = 0x 42002C00
[ISR_SERVO] TC_Timer::startTimer TC3 = 0x 42002C00
[ISR_SERVO] SAMD21 TC3 period = 10 , _prescaler = 1
[ISR_SERVO] _compareValue = 479
[ISR_SERVO] Starting  ITimer OK
Setup OK, Servo index = 0
Setup OK, Servo index = 1
Setup OK, Servo index = 2
Servos @ 0 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos @ 90 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 162 , pos = 90
90, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 162 , pos = 90
1620
Servos @ 180 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 245 , pos = 180
180, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 245 , pos = 180
2450
Servos sweeps from 0-180 degrees
Servos @ 0 degree
Servos idx = 0, act. pos. (deg) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 0
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 1, act. pos. (deg) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 1
[ISR_SERVO] cnt = 80 , pos = 0
800
Servos idx = 2, act. pos. (deg) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
0, pulseWidth (us) = [ISR_SERVO] Idx = 2
[ISR_SERVO] cnt = 80 , pos = 0
800


Debug

Debug is enabled by default on Serial.

You can also change the debugging level from 0 to 2. Be careful and using level 2 only for temporary debug purpose only.

#define ISR_SERVO_DEBUG             1

Troubleshooting

If you get compilation errors, more often than not, you may need to install a newer version of the core for Arduino boards.

Sometimes, the library will only work if you update the board core to the latest version because I am using newly added functions.



Issues

Submit issues to: SAMD_ISR_Servo issues



TO DO

  1. Search for bug and improvement.

DONE

  1. Similar features for Arduino (UNO, Mega, etc...), ESP32, ESP8266, STM32 and RP2040
  2. Add functions getPosition() and getPulseWidth()
  3. Optimize the code
  4. Add complicated examples
  5. Convert to h-only style.
  6. Optimize library code by using reference-passing instead of value-passing
  7. Display informational warning only when ISR_SERVO_DEBUG > 1
  8. Add support to many more boards, such as SAMD21E1xA, SAMD21G1xA andSAMD21J1xA
  9. Add astyle using allman style. Restyle the library


Contributions and thanks

Many thanks for everyone for bug reporting, new feature suggesting, testing and contributing to the development of this library. Especially to these people who have directly or indirectly contributed to this SAMD_ISR_Servo library


Contributing

If you want to contribute to this project:

  • Report bugs and errors
  • Ask for enhancements
  • Create issues and pull requests
  • Tell other people about this library

License

  • The library is licensed under MIT

Copyright

Copyright (c) 2021- Khoi Hoang