Hi. I have a STM32F3Discovery card, from that i try to control a Blue Robotics Basic ESC and a M100 motor. I set it up using STM32CudeIDE for a 50Hz PWM signal on PA15. The problem is to send a 1500 microseconds initzialization signal. How do i do th

[MHelg.1]

Below are example code for Arduino provided in the Basic Esc documentation

#include <Servo.h>

byte servoPin = 9;

Servo servo;

void setup() {

servo.attach(servoPin);

servo.writeMicroseconds(1500); // send "stop" signal to ESC.

delay(7000); // delay to allow the ESC to recognize the stopped signal

}

void loop() {

int signal = 1700; // Set signal value, which should be between 1100 and 1900

servo.writeMicroseconds(signal); // Send signal to ESC.

}

[KnarfB]

__HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, pulse_width);

The pulse width depends on the timer prescaler and period. You might set the prescaler such that timer clock is 1MHz. Then a 50 Hz period corresponds to a period length of 20000 (µs). Note that everything counts from 0. So you set the upper limit to 20000-1 and the prescaler to e.g. 48-1 if the SysClock is 48 MHz.

hth

KnarfB

[MHelg.1]

Thank you. I`ve set it up using 48MHz, Prescaler 47, Counter Period 19999 and Pulse 10000. I got a 50 Hz signal with period length 20000 µs.

Below are my code. I get a 1500 µs pulse (Initzialization signal) but i want a delay for 2 seconds and then give a 1700 µs to run the motor. This does not happen?

 /* USER CODE BEGIN 2 */

 HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1); // Starter PWM

 /* USER CODE END 2 */

 /* Infinite loop */

 /* USER CODE BEGIN WHILE */

 while (1)

 {

 __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_1, 1500);

 HAL_Delay(2000);

 __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_1, 1700);

  /* USER CODE END WHILE */

Attached are oscilloscope print and motor diagram if needed.

[Tesla DeLorean]

Do you delay after the second setting? Should this be in a loop?

​

Scope isn't showing multiple seconds, diagram the waveform you actually want to see.

[MHelg.1]

I initialize a 1500 µs pulse and then delay for 2 seconds. I tried to move it outside the loop (see code below).

 /* USER CODE BEGIN 2 */

 HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1); // Start PWM

 /* USER CODE END 2 */

 __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_1, 1500); // Initialization signal

 HAL_Delay(2000); // Delay 2 seconds

 __HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_1, 1700); // Run motor

Still doesent change after 2 seconds to a 1700 µs pulse. Is it possible that i have reset the timer before sending a new signal?

[KnarfB]

No, you don't have to reset. The __HAL macro results in a single register write and that's fine.

Your code should work. Are you sure that the last line is reached, i.e. HAL_Delay is working okay (needs SysTick running, not in interrupt).

[MHelg.1]

I tried to make a new prosject since i have change a lot of configurations during my troubleshooting.

Verifed the HAL_Delay on my oscilloscope, and now it changes to 1700 µs after 2 seconds!

Fantastic, but my motor wont run. If you guys cant fint anything wrong with my code i suspect the ESC to be defect..

Anyway thanks for your help

2 seconds delay 1700 µsSTM32CubeIDE setup

[KnarfB]

ESC has typically a dead-zone around the neutral value (although your diagram doesn't show one). You could carefully try larger values or put the scope at the ESC output.