stm32F103zet只有固定的幾個針腳可以輸出tim定時器訊號，在不支援tim輸出的口上就沒法輸出pwm，在紅牛開發版上的表現就是控制lcd螢幕亮度的a1針腳，可以輸出pwm，螢幕亮度可以無極調節，但是4個led燈就只能控制開關。使用arduino的analogWrite函式，只能調節開關。
可以用定時器的中斷來控制普通io口的開關，達到模擬pwm調製的結果。參考這文章 STM32普通io口模擬pwm輸出的三種方法_普通io口模擬輸出pwm-CSDN部落格
這裡使用第一個辦法。使用的是arduino的庫 STM32TimerInterrupt，避免了對tim結構體的複雜操作。使用的是紅牛開發板
/**************************************************************************************************************************** TimerInterruptLEDDemo.ino For STM32 boards Written by Khoi Hoang Built by Khoi Hoang https://github.com/khoih-prog/STM32_TimerInterrupt Licensed under MIT license Now even you use all these new 16 ISR-based timers,with their maximum interval practically unlimited (limited only by unsigned long miliseconds), you just consume only one STM32 timer and avoid conflicting with other cores' tasks. 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. *****************************************************************************************************************************/ /* Notes: Special design is necessary to share data between interrupt code and the rest of your program. Variables usually need to be "volatile" types. Volatile tells the compiler to avoid optimizations that assume variable can not spontaneously change. Because your function may change variables while your program is using them, the compiler needs this hint. But volatile alone is often not enough. When accessing shared variables, usually interrupts must be disabled. Even with volatile, if the interrupt changes a multi-byte variable between a sequence of instructions, it can be read incorrectly. If your data is multiple variables, such as an array and a count, usually interrupts need to be disabled or the entire sequence of your code which accesses the data. */ #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 // These define's must be placed at the beginning before #include "STM32TimerInterrupt.h" // _TIMERINTERRUPT_LOGLEVEL_ from 0 to 4 // Don't define _TIMERINTERRUPT_LOGLEVEL_ > 0. Only for special ISR debugging only. Can hang the system. // Don't define TIMER_INTERRUPT_DEBUG > 2. Only for special ISR debugging only. Can hang the system. #define TIMER_INTERRUPT_DEBUG 1 #define _TIMERINTERRUPT_LOGLEVEL_ 4 #include "STM32TimerInterrupt.h" // #ifndef LED_BUILTIN #define LED_BUILTIN PF6 // Pin 33/PB0 control on-board LED_GREEN on F767ZI // #endif #ifndef LED_BLUE #define LED_BLUE PF7 // Pin 73/PB7 control on-board LED_BLUE on F767ZI #endif #ifndef LED_RED #define LED_RED PF8 // Pin 74/PB14 control on-board LED_BLUE on F767ZI #endif #include "STM32TimerInterrupt.h" #include "STM32_ISR_Timer.h" #define TIMER_INTERVAL_MS 100 #define HW_TIMER_INTERVAL_MS 50 // Depending on the board, you can select STM32 Hardware Timer from TIM1-TIM22 // For example, F767ZI can select Timer from TIM1-TIM14 // If you select a Timer not correctly, you'll get a message from ci[ompiler // 'TIMxx' was not declared in this scope; did you mean 'TIMyy'? // Init STM32 timer TIM1 STM32Timer ITimer(TIM1); // Init STM32_ISR_Timer // Each STM32_ISR_Timer can service 16 different ISR-based timers STM32_ISR_Timer ISR_Timer; #define TIMER_INTERVAL_0_5S 500L #define TIMER_INTERVAL_1S 1000L #define TIMER_INTERVAL_1_5S 1500L void TimerHandler() { ISR_Timer.run(); } // In STM32, avoid doing something fancy in ISR, for example complex Serial.print with String() argument // The pure simple Serial.prints here are just for demonstration and testing. Must be eliminate in working environment // Or you can get this run-time error / crash unsigned int count=0; unsigned int i = 1;//i就是佔空比 void doingSomething1() { count++;//計中斷次數 if(count%100<i)//i：佔空比值， digitalWrite(LED_BUILTIN, 1);//高電平 else digitalWrite(LED_BUILTIN, 0);//高電平; //digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN)); } void doingSomething2() { digitalWrite(LED_BLUE, !digitalRead(LED_BLUE)); } void doingSomething3() { digitalWrite(LED_RED, !digitalRead(LED_RED)); } void setup() { Serial.begin(115200); while (!Serial); delay(100); Serial.print(F("\nStarting TimerInterruptLEDDemo on ")); Serial.println(BOARD_NAME); Serial.println(STM32_TIMER_INTERRUPT_VERSION); Serial.print(F("CPU Frequency = ")); Serial.print(F_CPU / 1000000); Serial.println(F(" MHz")); // Instantiate HardwareTimer object. Thanks to 'new' instanciation, HardwareTimer is not destructed when setup() function is finished. //HardwareTimer *MyTim = new HardwareTimer(Instance); // configure pin in output mode pinMode(LED_BUILTIN, OUTPUT); pinMode(LED_BLUE, OUTPUT); pinMode(LED_RED, OUTPUT); // Interval in microsecs if (ITimer.attachInterruptInterval(HW_TIMER_INTERVAL_MS*1000 , TimerHandler))//過小的HW_TIMER_INTERVAL_MS會導致loop無法執行，這裡測試過不需要調節 { Serial.print(F("Starting ITimer OK, millis() = ")); Serial.println(millis()); } else Serial.println(F("Can't set ITimer. Select another freq. or timer")); // Just to demonstrate, don't use too many ISR Timers if not absolutely necessary // You can use up to 16 timer for each ISR_Timer //ISR_Timer.setInterval(1000, doingSomething1); ITimer.setFrequency(100000, doingSomething1);//實測200k頻率可以執行，300k不行，使用這個函式可以突破1ms的間隔限制 ISR_Timer.setInterval(TIMER_INTERVAL_1S, doingSomething2); ISR_Timer.setInterval(TIMER_INTERVAL_1_5S, doingSomething3); } void loop() { /* Nothing to do all is done by hardware. Even no interrupt required. */ i++; //Serial.println(count); Serial.println(i); delay(40); if(i == 100) { i = 0; }//迴圈調節佔空比，用來演示燈亮度變化 }