STM32_ISR_Servo Library

---

---

Table of Contents

• Important Change from v1.1.0
• Why do we need this STM32_ISR_Servo library
  • Features
  • Important Notes about using ISR
  • Currently supported Boards
• Changelog
• Prerequisites
• Installation
  • Use Arduino Library Manager
  • Manual Install
  • VS Code & PlatformIO
• HOWTO Fix Multiple Definitions Linker Error
• More useful Information
  • STM32 Hardware Timers
  • New functions
  • What special in this STM32_ISR_Servo library
• HOWTO Usage
• Examples
  • 1. STM32_ISR_MultiServos
  • 2. STM32_MultipleRandomServos
  • 3. STM32_MultipleServos
  • 4. ISR_MultiServos
  • 5. MultipleRandomServos
  • 6. MultipleServos
  • 7. multiFileProject New
• Example STM32_ISR_MultiServos
• Debug Terminal Output Samples
  • 1. STM32_MultipleRandomServos on NUCLEO_F767ZI
  • 2. STM32_MultipleRandomServos on NUCLEO_H743ZI2
  • 3. STM32_ISR_MultiServos on NUCLEO_L552ZE_Q
• Debug
• Troubleshooting
• Issues
• TO DO
• DONE
• Contributions and Thanks
• Contributing
• License
• Copyright

---

---

Important Change from v1.1.0

Please have a look at HOWTO Fix Multiple Definitions Linker Error

---

---

Why do we need this STM32_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 STM32F/L/H/G/WB/MP1-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

1. STM32F/L/H/G/WB/MP1 boards (with 32+K Flash)

• Nucleo-144
• Nucleo-64
• Discovery
• Generic STM32F0, STM32F1, STM32F2, STM32F3, STM32F4, STM32F7 (with 64+K Flash): x8 and up
• STM32L0, STM32L1, STM32L4, STM32L5
• STM32G0, STM32G4
• STM32H7
• STM32WB
• STM32MP1
• LoRa boards
• 3-D printer boards
• Generic Flight Controllers
• Midatronics boards

---

---

Prerequisites

1. Arduino IDE 1.8.19+ for Arduino.
2. Arduino Core for STM32 v2.3.0+ for STM32F/L/H/G/WB/MP1 boards.

---

---

Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for STM32_ISR_Servo, then select / install the latest version. You can also use this link for more detailed instructions.

Manual Install

Another way to install is to:

1. Navigate to STM32_ISR_Servo page.
2. Download the latest release STM32_ISR_Servo-main.zip.
3. Extract the zip file to STM32_ISR_Servo-main directory
4. Copy whole STM32_ISR_Servo-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO

1. Install VS Code
2. Install PlatformIO
3. Install STM32_ISR_Servo library by using Library Manager. Search for STM32_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

---

---

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 "STM32_ISR_Servo.hpp"     //https://github.com/khoih-prog/STM32_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 "STM32_ISR_Servo.h"           //https://github.com/khoih-prog/STM32_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

---

---

More useful Information

STM32 Hardware Timers

The Timers of STM32s are numerous, yet very sophisticated and powerful.

In general, across the STM32 microcontrollers families, the timer peripherals that have the same name also have the same features set, but there are a few exceptions.

For example, the TIM1 timer peripheral is shared across the STM32F1 Series, STM32F2 Series and STM32F4 Series, but for the specific case of STM32F30x microcontrollers family, the TIM1 timer peripheral features a bit richer features set than the TIM1 present in the other families.

The general purpose timers embedded by the STM32 microcontrollers share the same backbone structure; they differ only on the level of features embedded by a given timer peripheral.

The level of features integration for a given timer peripheral is decided based on the applications field that it targets.

The timer peripherals can be classified as: • Advanced-configuration timers like TIM1 and TIM8 among others. • General-purpose configuration timers like TIM2 and TIM3 among others • Lite-configuration timers like TIM9, TIM10, TIM12 and TIM16 among others • Basic-configuration timers like TIM6 and TIM7 among others.

For example, STM32F103C8T6 has one advance timer, while STM32F103VET6 has two advanced timers. Nucleo-144 STM32F767ZI boards have 14 Timers, TIM1-TIM14.

More information can be found at Embedded-Lab STM32 TIMERS

To be sure which Timer is available for the board you're using, check the Core Package's related files. For example, for Nucleo-144 STM32F767ZI, check these files:

1. ~/.arduino15/packages/STM32/hardware/stm32/1.9.0/system/Drivers/CMSIS/Device/ST/STM32F7xx/Include/stm32f7xx.h
2. ~/.arduino15/packages/STM32/hardware/stm32/1.9.0/system/Drivers/CMSIS/Device/ST/STM32F7xx/Include/stm32f767xx.h

The information will be as follows:

typedef struct
{
  __IO uint32_t CR1;         /*!< TIM control register 1,              Address offset: 0x00 */
  __IO uint32_t CR2;         /*!< TIM control register 2,              Address offset: 0x04 */
  __IO uint32_t SMCR;        /*!< TIM slave mode control register,     Address offset: 0x08 */
  __IO uint32_t DIER;        /*!< TIM DMA/interrupt enable register,   Address offset: 0x0C */
  __IO uint32_t SR;          /*!< TIM status register,                 Address offset: 0x10 */
  __IO uint32_t EGR;         /*!< TIM event generation register,       Address offset: 0x14 */
  __IO uint32_t CCMR1;       /*!< TIM capture/compare mode register 1, Address offset: 0x18 */
  __IO uint32_t CCMR2;       /*!< TIM capture/compare mode register 2, Address offset: 0x1C */
  __IO uint32_t CCER;        /*!< TIM capture/compare enable register, Address offset: 0x20 */
  __IO uint32_t CNT;         /*!< TIM counter register,                Address offset: 0x24 */
  __IO uint32_t PSC;         /*!< TIM prescaler,                       Address offset: 0x28 */
  __IO uint32_t ARR;         /*!< TIM auto-reload register,            Address offset: 0x2C */
  __IO uint32_t RCR;         /*!< TIM repetition counter register,     Address offset: 0x30 */
  __IO uint32_t CCR1;        /*!< TIM capture/compare register 1,      Address offset: 0x34 */
  __IO uint32_t CCR2;        /*!< TIM capture/compare register 2,      Address offset: 0x38 */
  __IO uint32_t CCR3;        /*!< TIM capture/compare register 3,      Address offset: 0x3C */
  __IO uint32_t CCR4;        /*!< TIM capture/compare register 4,      Address offset: 0x40 */
  __IO uint32_t BDTR;        /*!< TIM break and dead-time register,    Address offset: 0x44 */
  __IO uint32_t DCR;         /*!< TIM DMA control register,            Address offset: 0x48 */
  __IO uint32_t DMAR;        /*!< TIM DMA address for full transfer,   Address offset: 0x4C */
  __IO uint32_t OR;          /*!< TIM option register,                 Address offset: 0x50 */
  __IO uint32_t CCMR3;       /*!< TIM capture/compare mode register 3,      Address offset: 0x54 */
  __IO uint32_t CCR5;        /*!< TIM capture/compare mode register5,       Address offset: 0x58 */
  __IO uint32_t CCR6;        /*!< TIM capture/compare mode register6,       Address offset: 0x5C */
  __IO uint32_t AF1;         /*!< TIM Alternate function option register 1, Address offset: 0x60 */
  __IO uint32_t AF2;         /*!< TIM Alternate function option register 2, Address offset: 0x64 */

} TIM_TypeDef;

and

#define PERIPH_BASE            0x40000000UL /*!< Base address of : AHB/ABP Peripherals   
/*!< Peripheral memory map */
#define APB1PERIPH_BASE        PERIPH_BASE

/*!< APB1 peripherals */
#define TIM2_BASE             (APB1PERIPH_BASE + 0x0000UL)
#define TIM3_BASE             (APB1PERIPH_BASE + 0x0400UL)
#define TIM4_BASE             (APB1PERIPH_BASE + 0x0800UL)
#define TIM5_BASE             (APB1PERIPH_BASE + 0x0C00UL)
#define TIM6_BASE             (APB1PERIPH_BASE + 0x1000UL)
#define TIM7_BASE             (APB1PERIPH_BASE + 0x1400UL)
#define TIM12_BASE            (APB1PERIPH_BASE + 0x1800UL)
#define TIM13_BASE            (APB1PERIPH_BASE + 0x1C00UL)
#define TIM14_BASE            (APB1PERIPH_BASE + 0x2000UL)

/*!< APB2 peripherals */
#define TIM1_BASE             (APB2PERIPH_BASE + 0x0000UL)
#define TIM8_BASE             (APB2PERIPH_BASE + 0x0400UL)
#define TIM9_BASE             (APB2PERIPH_BASE + 0x4000UL)
#define TIM10_BASE            (APB2PERIPH_BASE + 0x4400UL)
#define TIM11_BASE            (APB2PERIPH_BASE + 0x4800UL)

...

#define TIM2                ((TIM_TypeDef *) TIM2_BASE)
#define TIM3                ((TIM_TypeDef *) TIM3_BASE)
#define TIM4                ((TIM_TypeDef *) TIM4_BASE)
#define TIM5                ((TIM_TypeDef *) TIM5_BASE)
#define TIM6                ((TIM_TypeDef *) TIM6_BASE)
#define TIM7                ((TIM_TypeDef *) TIM7_BASE)
#define TIM12               ((TIM_TypeDef *) TIM12_BASE)
#define TIM13               ((TIM_TypeDef *) TIM13_BASE)
#define TIM14               ((TIM_TypeDef *) TIM14_BASE)
...
#define TIM1                ((TIM_TypeDef *) TIM1_BASE)
#define TIM8                ((TIM_TypeDef *) TIM8_BASE)
...
#define TIM9                ((TIM_TypeDef *) TIM9_BASE)
#define TIM10               ((TIM_TypeDef *) TIM10_BASE)
#define TIM11               ((TIM_TypeDef *) TIM11_BASE)

New functions

// returns last position in degrees if success, or -1 on wrong servoIndex
int getPosition(unsigned servoIndex);

// returns pulseWidth in microsecs (within min/max range) if success, or 0 on wrong servoIndex
unsigned int getPulseWidth(unsigned servoIndex);

What special in this STM32_ISR_Servo library

Now these new 16 ISR-based Servo controllers just use one STM32 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 STM32_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:

STM32_ISR_Servo/examples/STM32_MultipleServos/STM32_MultipleServos.ino

Lines 42 to 153 in 46cbae9

	#if !( defined(STM32F0) || defined(STM32F1) || defined(STM32F2) || defined(STM32F3) ||defined(STM32F4) || defined(STM32F7) || \
	defined(STM32L0) || defined(STM32L1) || defined(STM32L4) || defined(STM32H7) ||defined(STM32G0) || defined(STM32G4) || \
	defined(STM32WB) || defined(STM32MP1) || defined(STM32L5))
	#error This code is designed to run on STM32F/L/H/G/WB/MP1 platform! Please check your Tools->Board setting.
	#endif
	#define TIMER_INTERRUPT_DEBUG 0
	#define ISR_SERVO_DEBUG 1
	// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
	#include "STM32_ISR_Servo.h"
	// Default is TIMER_SERVO (TIM7 for many boards)
	#define USE_STM32_TIMER_NO TIMER_SERVO
	// Published values for SG90 servos; adjust if needed
	#define MIN_MICROS 800 //544
	#define MAX_MICROS 2450
	#define SERVO_PIN_1 D1
	#define SERVO_PIN_2 D2
	#define SERVO_PIN_3 D3
	#define SERVO_PIN_4 D4
	#define SERVO_PIN_5 D5
	#define SERVO_PIN_6 D6
	typedef struct
	{
	int servoIndex;
	uint8_t servoPin;
	} ISR_servo_t;
	#if ( defined(STM32L0) || defined(STM32L1) || defined(STM32L4) || defined(STM32L5) )
	#define NUM_SERVOS 3
	ISR_servo_t ISR_servo[NUM_SERVOS] =
	{
	{ -1, SERVO_PIN_1 }, { -1, SERVO_PIN_2 }, { -1, SERVO_PIN_3 }
	};
	#else
	#define NUM_SERVOS 6
	ISR_servo_t ISR_servo[NUM_SERVOS] =
	{
	{ -1, SERVO_PIN_1 }, { -1, SERVO_PIN_2 }, { -1, SERVO_PIN_3 }, { -1, SERVO_PIN_4 }, { -1, SERVO_PIN_5 }, { -1, SERVO_PIN_6 }
	};
	#endif
	void setup()
	{
	Serial.begin(115200);
	while (!Serial);
	delay(200);
	Serial.print(F("\nStarting STM32_MultipleServos on ")); Serial.println(BOARD_NAME);
	Serial.println(STM32_ISR_SERVO_VERSION);
	//Select STM32 timer USE_STM32_TIMER_NO
	STM32_ISR_Servos.useTimer(USE_STM32_TIMER_NO);
	for (int index = 0; index < NUM_SERVOS; index++)
	{
	ISR_servo[index].servoIndex = STM32_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);
	}
	}
	}
	void loop()
	{
	int position; // position in degrees
	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++)
	{
	STM32_ISR_Servos.setPosition(ISR_servo[index].servoIndex, (position + index * (180 / NUM_SERVOS)) % 180 );
	}
	// waits 1s for the servo to reach the position
	delay(1000);
	}
	for (position = 180; position >= 0; position -= 5)
	{
	// goes from 0 degrees to 180 degrees
	// in steps of 1 degree
	for (int index = 0; index < NUM_SERVOS; index++)
	{
	STM32_ISR_Servos.setPosition(ISR_servo[index].servoIndex, (position + index * (180 / NUM_SERVOS)) % 180);
	}
	// waits 1s for the servo to reach the position
	delay(1000);
	}
	delay(5000);
	}

---

---

Examples:

1. STM32_ISR_MultiServos
2. STM32_MultipleRandomServos
3. STM32_MultipleServos
4. ISR_MultiServos
5. MultipleRandomServos
6. MultipleServos
7. multiFileProject

---

---

Example STM32_ISR_MultiServos

STM32_ISR_Servo/examples/STM32_ISR_MultiServos/STM32_ISR_MultiServos.ino

Lines 42 to 136 in 9dd199d

	#if !( defined(STM32F0) || defined(STM32F1) || defined(STM32F2) || defined(STM32F3) ||defined(STM32F4) || defined(STM32F7) || \
	defined(STM32L0) || defined(STM32L1) || defined(STM32L4) || defined(STM32H7) ||defined(STM32G0) || defined(STM32G4) || \
	defined(STM32WB) || defined(STM32MP1) || defined(STM32L5))
	#error This code is designed to run on STM32F/L/H/G/WB/MP1 platform! Please check your Tools->Board setting.
	#endif
	#define TIMER_INTERRUPT_DEBUG 0
	#define ISR_SERVO_DEBUG 1
	// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
	#include "STM32_ISR_Servo.h"
	// Default is TIMER_SERVO (TIM7 for many boards)
	#define USE_STM32_TIMER_NO TIMER_SERVO
	// Published values for SG90 servos; adjust if needed
	#define MIN_MICROS 800 //544
	#define MAX_MICROS 2450
	#define SERVO_PIN_1 D6
	#define SERVO_PIN_2 D7
	int servoIndex1 = -1;
	int servoIndex2 = -1;
	void setup()
	{
	Serial.begin(115200);
	while (!Serial);
	delay(500);
	Serial.print(F("\nStarting STM32_ISR_MultiServos on ")); Serial.println(BOARD_NAME);
	Serial.println(STM32_ISR_SERVO_VERSION);
	//Select STM32 timer USE_STM32_TIMER_NO
	STM32_ISR_Servos.useTimer(USE_STM32_TIMER_NO);
	servoIndex1 = STM32_ISR_Servos.setupServo(SERVO_PIN_1, MIN_MICROS, MAX_MICROS);
	servoIndex2 = STM32_ISR_Servos.setupServo(SERVO_PIN_2, MIN_MICROS, MAX_MICROS);
	if (servoIndex1 != -1)
	Serial.println(F("Setup Servo1 OK"));
	else
	Serial.println(F("Setup Servo1 failed"));
	if (servoIndex2 != -1)
	Serial.println(F("Setup Servo2 OK"));
	else
	Serial.println(F("Setup Servo2 failed"));
	}
	void loop()
	{
	int position;
	if ( ( servoIndex1 != -1) && ( servoIndex2 != -1) )
	{
	for (position = 0; position <= 180; position++)
	{
	// goes from 0 degrees to 180 degrees
	// in steps of 1 degree
	if (position % 30 == 0)
	{
	Serial.print(F("Servo1 pos = ")); Serial.print(position);
	Serial.print(F(", Servo2 pos = ")); Serial.println(180 - position);
	}
	STM32_ISR_Servos.setPosition(servoIndex1, position);
	STM32_ISR_Servos.setPosition(servoIndex2, 180 - position);
	// waits 30ms for the servo to reach the position
	delay(30);
	}
	delay(5000);
	for (position = 180; position >= 0; position--)
	{
	// goes from 180 degrees to 0 degrees
	if (position % 30 == 0)
	{
	Serial.print(F("Servo1 pos = ")); Serial.print(position);
	Serial.print(F(", Servo2 pos = ")); Serial.println(180 - position);
	}
	STM32_ISR_Servos.setPosition(servoIndex1, position);
	STM32_ISR_Servos.setPosition(servoIndex2, 180 - position);
	// waits 30ms for the servo to reach the position
	delay(30);
	}
	delay(5000);
	}
	}

---

---

Debug Terminal Output Samples

1. STM32_MultipleRandomServos on NUCLEO_F767ZI

Starting STM32_MultipleRandomServos on NUCLEO_F767ZI
STM32_ISR_Servo v1.1.0
[ISR_SERVO] STM32TimerInterrupt: Timer Input Freq (Hz) = 108000000
[ISR_SERVO] Frequency = 1000000.00 , _count = 10
[ISR_SERVO] Starting  ITimer OK
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
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

---

2. STM32_MultipleRandomServos on NUCLEO_H743ZI2

Starting STM32_MultipleRandomServos on NUCLEO_H743ZI2
STM32_ISR_Servo v1.1.0
[ISR_SERVO] STM32TimerInterrupt: Timer Input Freq (Hz) = 240000000
[ISR_SERVO] Frequency = 1000000.00 , _count = 10
[ISR_SERVO] Starting  ITimer OK
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
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

---

3. STM32_ISR_MultiServos on NUCLEO_L552ZE_Q

Starting STM32_ISR_MultiServos on NUCLEO_L552ZE_Q
STM32_ISR_Servo v1.1.0
[ISR_SERVO] STM32TimerInterrupt: Timer Input Freq (Hz) = 110000000
[ISR_SERVO] Frequency = 1000000.00 , _count = 10
[ISR_SERVO] Starting  ITimer OK
Setup Servo1 OK
Setup Servo2 OK
Servo1 pos = 0, Servo2 pos = 180
Servo1 pos = 30, Servo2 pos = 150
Servo1 pos = 60, Servo2 pos = 120
Servo1 pos = 90, Servo2 pos = 90
Servo1 pos = 120, Servo2 pos = 60
Servo1 pos = 150, Servo2 pos = 30
Servo1 pos = 180, Servo2 pos = 0
Servo1 pos = 180, Servo2 pos = 0
Servo1 pos = 150, Servo2 pos = 30
Servo1 pos = 120, Servo2 pos = 60
Servo1 pos = 90, Servo2 pos = 90
Servo1 pos = 60, Servo2 pos = 120
Servo1 pos = 30, Servo2 pos = 150
Servo1 pos = 0, Servo2 pos = 180
Servo1 pos = 0, Servo2 pos = 180
Servo1 pos = 30, Servo2 pos = 150
Servo1 pos = 60, Servo2 pos = 120
Servo1 pos = 90, Servo2 pos = 90
Servo1 pos = 120, Servo2 pos = 60
Servo1 pos = 150, Servo2 pos = 30
Servo1 pos = 180, Servo2 pos = 0

---

---

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 TIMER_INTERRUPT_DEBUG       1
#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: STM32_ISR_Servo issues

---

---

TO DO

1. Search for bug and improvement.

---

DONE

1. Similar features for Arduino (UNO, Mega, etc...), ESP32 and ESP8266
2. Add functions getPosition() and getPulseWidth()
3. Optimize the code
4. Add more complicated examples
5. Convert to h-only library.
6. Optimize library code by using reference-passing instead of value-passing
7. Improve accuracy by using float, instead of uint32_t for position in degrees
8. Add example multiFileProject to demo for multiple-file project
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 STM32_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