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timerarduinostm32pwm

PWM via STM32F446RE Timer on alternative pins in Arduino IDE

I am trying to implement a PWM-signal with the STM32 Timers in Visual Studio Code and in the Arduino IDE. I am using a Nucleo F446RE Board.

I have the following code working well within VSC:

#include <Arduino.h>

HardwareTimer* Timer3 = new HardwareTimer(TIM3);

void setup() {
  Timer3->setMode(4, TIMER_OUTPUT_COMPARE_PWM1, PB_1_ALT1);
  Timer3->setPrescaleFactor(90);
  Timer3->setCaptureCompare(4, 1000, TICK_COMPARE_FORMAT);
  Timer3->setOverflow(5000, TICK_FORMAT);
  Timer3->resume();
}

void loop() { }

If I try to compile the same code in the Arduino IDE I get the following error:

'PB_1_ALT1' was not declared in this scope

So I tried to include the PeripheralPins.h manually because the PeripheralPins.c defines PB_1_ALT1 but it did not solve the problem. Next I looked the definition of PB_1_ALT1 up which looks like this:

PB_1_ALT1 = PB_1 | ALT1
ALT1 = 0x100

But the Arduino IDE doesn't know ALT1 either, therefore I changed the setMode-command to:

Timer3->setMode(4, TIMER_OUTPUT_COMPARE_PWM1, PB_1 | 0x100);

This time the code gets compiled and it is possible to upload it but the pin still does not output anything.

Therefore my questions:

  1. How do I use the alternative output pins of the timers in the Arduino IDE correctly?
  2. The PeripheralPins.c gives a list of all possible Timer-Channel-Pin-combinations. But where do I find these combinations in the datasheet? I only found them randomly in the code but nowhere in the datasheet of the STM32F446RE.
Solution

  • Solution to question 1!

    The PWM-pin combinations are stored in:

    []\AppData\Local\Arduino15\packages\STM32\hardware\stm32\1.9.0\variants\NUCLEO_F446RE\PeripheralPins.c

    The file does not include the alternative pin combinations with different names like in the library for VSC. Instead you have to uncomment the combination you like to use and comment the normal one.

    Hint

    Directly editing this library would change the PWM-settings for all programs. Therefore I suggest to copy the whole table into a new c-file in the program's folder. It has to include the corresponding h-file which can be included this in the program.

    Own_PeripheralPins.c:

    #include "Own_PeripheralPins.h"
#include <Arduino.h>

const PinMap PinMap_PWM[] = {
  {PA_0,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 1, 0)}, // TIM2_CH1
  //  {PA_0,  TIM5,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM5, 1, 0)}, // TIM5_CH1
  //  {PA_1,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 2, 0)}, // TIM2_CH2
  {PA_1,  TIM5,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM5, 2, 0)}, // TIM5_CH2
  //  {PA_2,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 3, 0)}, // TIM2_CH3 - STLink Tx
  //  {PA_2,  TIM5,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM5, 3, 0)}, // TIM5_CH3 - STLink Tx
  //  {PA_2,  TIM9,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM9, 1, 0)}, // TIM9_CH1 - STLink Tx
  //  {PA_3,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 4, 0)}, // TIM2_CH4 - STLink Rx
  //  {PA_3,  TIM5,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM5, 4, 0)}, // TIM5_CH4 - STLink Rx
  //  {PA_3,  TIM9,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM9, 2, 0)}, // TIM9_CH2 - STLink Rx
  {PA_5,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 1, 0)}, // TIM2_CH1
  //  {PA_5,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 1, 1)}, // TIM8_CH1N
  //  {PA_6,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 1, 0)}, // TIM3_CH1
  {PA_6,  TIM13,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_TIM13, 1, 0)}, // TIM13_CH1
  //  {PA_7,  TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 1, 1)}, // TIM1_CH1N
  //  {PA_7,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 2, 0)}, // TIM3_CH2
  //  {PA_7,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 1, 1)}, // TIM8_CH1N
  {PA_7,  TIM14,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_TIM14, 1, 0)}, // TIM14_CH1
  {PA_8,  TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 1, 0)}, // TIM1_CH1
  {PA_9,  TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 2, 0)}, // TIM1_CH2
  {PA_10, TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 3, 0)}, // TIM1_CH3
  {PA_11, TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 4, 0)}, // TIM1_CH4
  {PA_15, TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 1, 0)}, // TIM2_CH1
  //  {PB_0,  TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 2, 1)}, // TIM1_CH2N
  //  {PB_0,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 3, 0)}, // TIM3_CH3
  {PB_0,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 2, 1)}, // TIM8_CH2N
  //  {PB_1,  TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 3, 1)}, // TIM1_CH3N
  //  {PB_1,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 4, 0)}, // TIM3_CH4
  {PB_1,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 3, 1)}, // TIM8_CH3N
  {PB_2,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 4, 0)}, // TIM2_CH4
  {PB_3,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 2, 0)}, // TIM2_CH2
  {PB_4,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 1, 0)}, // TIM3_CH1
  {PB_5,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 2, 0)}, // TIM3_CH2
  {PB_6,  TIM4,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM4, 1, 0)}, // TIM4_CH1
  {PB_7,  TIM4,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM4, 2, 0)}, // TIM4_CH2
  //  {PB_8,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 1, 0)}, // TIM2_CH1
  {PB_8,  TIM4,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM4, 3, 0)}, // TIM4_CH3
  //  {PB_8,  TIM10,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM10, 1, 0)}, // TIM10_CH1
  //  {PB_9,  TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 2, 0)}, // TIM2_CH2
  //  {PB_9,  TIM4,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM4, 4, 0)}, // TIM4_CH4
  {PB_9,  TIM11,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM11, 1, 0)}, // TIM11_CH1
  {PB_10, TIM2,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM2, 3, 0)}, // TIM2_CH3
  {PB_13, TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 1, 1)}, // TIM1_CH1N
  //  {PB_14, TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 2, 1)}, // TIM1_CH2N
  //  {PB_14, TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 2, 1)}, // TIM8_CH2N
  {PB_14, TIM12,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_TIM12, 1, 0)}, // TIM12_CH1
  //  {PB_15, TIM1,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM1, 3, 1)}, // TIM1_CH3N
  //  {PB_15, TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 3, 1)}, // TIM8_CH3N
  {PB_15, TIM12,  STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF9_TIM12, 2, 0)}, // TIM12_CH2
  {PC_6,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 1, 0)}, // TIM3_CH1
  //  {PC_6,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 1, 0)}, // TIM8_CH1
  //  {PC_7,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 2, 0)}, // TIM3_CH2
  {PC_7,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 2, 0)}, // TIM8_CH2
  {PC_8,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 3, 0)}, // TIM3_CH3
  //  {PC_8,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 3, 0)}, // TIM8_CH3
  //  {PC_9,  TIM3,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM3, 4, 0)}, // TIM3_CH4
  {PC_9,  TIM8,   STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM8, 4, 0)}, // TIM8_CH4
  {NC,    NP,    0}
};

    Important: The attribute weak has to be removed!

    Important: This table has to be adjusted for the individually used STM-type!

    I would prefer directly defining the PinMap_PWM in the header file but I don't know how to do this or wheter it is even possible. If the file is included by multiple other files, I get a multiple definition error. Neither it is possible to set the pointer constant nor static, because there would be different types of defition of the variable.