Operating system
Development tools
Security and connectivity
Important update: Arm Announces End of Life Timeline for Mbed. This site will be archived in July 2026. Read the full announcement.
mbed library sources
Dependents: Encrypted my_mbed lklk CyaSSL_DTLS_Cellular ... more
Issue:- When using the pwmout_api as below the instead of a 1KHz for the 1ms period then it results in 500Hz or PWM1/1 and 2KHz for PWM3/1 (Checked with PWM2 and PWM4 both same as PWM3) for the NUCLEO-STM32F401RE but since this is used for the NUCLEO STM32F4 I suspect others may be affected also.
#include "mbed.h" PwmOut mypwm(PA_6); //PWM3/1 PwmOut mypwm2(PA_7); //PWM1/1N DigitalOut myled(LED1); int main() { mypwm.period_ms(1); mypwm.pulsewidth_us(500); mypwm2.period_ms(1); mypwm2.pulsewidth_us(500); while(1) { myled = !myled; wait(1); } }
Source:-
mbed-src/targets/hal/TARGET_STM/TARGET_STM32F4/pwmout_api.c
Correction Required:- Divisor incorrectly applied to above API on Lines 244 and 246 Change required at * lines
/* mbed Microcontroller Library ******************************************************************************* * Copyright (c) 2014, STMicroelectronics * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. Neither the name of STMicroelectronics nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ******************************************************************************* */ #include "pwmout_api.h" #if DEVICE_PWMOUT #include "cmsis.h" #include "pinmap.h" #include "mbed_error.h" #include "PeripheralPins.h" static TIM_HandleTypeDef TimHandle; void pwmout_init(pwmout_t* obj, PinName pin) { // Get the peripheral name from the pin and assign it to the object obj->pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); // Get the functions (timer channel, (non)inverted) from the pin and assign it to the object uint32_t function = pinmap_function(pin, PinMap_PWM); MBED_ASSERT(function != (uint32_t)NC); obj->channel = STM_PIN_CHANNEL(function); obj->inverted = STM_PIN_INVERTED(function); if (obj->pwm == (PWMName)NC) { error("PWM error: pinout mapping failed."); } // Enable TIM clock if (obj->pwm == PWM_1) __TIM1_CLK_ENABLE(); if (obj->pwm == PWM_2) __TIM2_CLK_ENABLE(); if (obj->pwm == PWM_3) __TIM3_CLK_ENABLE(); if (obj->pwm == PWM_4) __TIM4_CLK_ENABLE(); #if defined(TIM8_BASE) if (obj->pwm == PWM_8) __TIM8_CLK_ENABLE(); #endif if (obj->pwm == PWM_9) __TIM9_CLK_ENABLE(); if (obj->pwm == PWM_10) __TIM10_CLK_ENABLE(); if (obj->pwm == PWM_11) __TIM11_CLK_ENABLE(); #if defined(TIM13_BASE) if (obj->pwm == PWM_13) __TIM13_CLK_ENABLE(); #endif #if defined(TIM14_BASE) if (obj->pwm == PWM_14) __TIM14_CLK_ENABLE(); #endif // Configure GPIO pinmap_pinout(pin, PinMap_PWM); obj->pin = pin; obj->period = 0; obj->pulse = 0; pwmout_period_us(obj, 20000); // 20 ms per default } void pwmout_free(pwmout_t* obj) { // Configure GPIO pin_function(obj->pin, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0)); } void pwmout_write(pwmout_t* obj, float value) { TIM_OC_InitTypeDef sConfig; int channel = 0; int complementary_channel = 0; TimHandle.Instance = (TIM_TypeDef *)(obj->pwm); if (value < (float)0.0) { value = 0.0; } else if (value > (float)1.0) { value = 1.0; } obj->pulse = (uint32_t)((float)obj->period * value); // Configure channels sConfig.OCMode = TIM_OCMODE_PWM1; sConfig.Pulse = obj->pulse; sConfig.OCPolarity = TIM_OCPOLARITY_HIGH; sConfig.OCNPolarity = TIM_OCNPOLARITY_HIGH; sConfig.OCFastMode = TIM_OCFAST_DISABLE; sConfig.OCIdleState = TIM_OCIDLESTATE_RESET; sConfig.OCNIdleState = TIM_OCNIDLESTATE_RESET; complementary_channel = obj->inverted; switch (obj->channel) { case 1: channel = TIM_CHANNEL_1; break; case 2: channel = TIM_CHANNEL_2; break; case 3: channel = TIM_CHANNEL_3; break; case 4: channel = TIM_CHANNEL_4; break; default: return; } HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, channel); if (complementary_channel) { HAL_TIMEx_PWMN_Start(&TimHandle, channel); } else { HAL_TIM_PWM_Start(&TimHandle, channel); } } float pwmout_read(pwmout_t* obj) { float value = 0; if (obj->period > 0) { value = (float)(obj->pulse) / (float)(obj->period); } return ((value > (float)1.0) ? (float)(1.0) : (value)); } void pwmout_period(pwmout_t* obj, float seconds) { pwmout_period_us(obj, seconds * 1000000.0f); } void pwmout_period_ms(pwmout_t* obj, int ms) { pwmout_period_us(obj, ms * 1000); } void pwmout_period_us(pwmout_t* obj, int us) { TimHandle.Instance = (TIM_TypeDef *)(obj->pwm); RCC_ClkInitTypeDef RCC_ClkInitStruct; uint32_t PclkFreq; uint32_t APBxCLKDivider; float dc = pwmout_read(obj); __HAL_TIM_DISABLE(&TimHandle); // Update the SystemCoreClock variable SystemCoreClockUpdate(); HAL_RCC_GetClockConfig(&RCC_ClkInitStruct, &PclkFreq); switch (obj->pwm) { case PWM_1: PclkFreq = HAL_RCC_GetPCLK2Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider; break; case PWM_2: PclkFreq = HAL_RCC_GetPCLK1Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider; break; case PWM_3: PclkFreq = HAL_RCC_GetPCLK1Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider; break; case PWM_4: PclkFreq = HAL_RCC_GetPCLK1Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider; break; #if defined(TIM8_BASE) case PWM_8: PclkFreq = HAL_RCC_GetPCLK2Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider; break; #endif case PWM_9: PclkFreq = HAL_RCC_GetPCLK2Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider; break; case PWM_10: PclkFreq = HAL_RCC_GetPCLK2Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider; break; case PWM_11: PclkFreq = HAL_RCC_GetPCLK2Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB2CLKDivider; break; #if defined(TIM13_BASE) case PWM_13: PclkFreq = HAL_RCC_GetPCLK1Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider; break; #endif #if defined(TIM14_BASE) case PWM_14: PclkFreq = HAL_RCC_GetPCLK1Freq(); APBxCLKDivider = RCC_ClkInitStruct.APB1CLKDivider; break; #endif default: return; } TimHandle.Init.Period = us - 1; if (APBxCLKDivider == RCC_HCLK_DIV1) TimHandle.Init.Prescaler = (uint16_t)((PclkFreq) / 1000000) - 1; // 1 s tick was PclkFreq*2 changed to PclkFreq else TimHandle.Init.Prescaler = (uint16_t)((PclkFreq*2) / 1000000) - 1; // 1 s tick was PclkFreq changed to PclkFreq*2 TimHandle.Init.ClockDivision = 0; TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP; HAL_TIM_PWM_Init(&TimHandle); // Set duty cycle again pwmout_write(obj, dc); // Save for future use obj->period = us; __HAL_TIM_ENABLE(&TimHandle); } void pwmout_pulsewidth(pwmout_t* obj, float seconds) { pwmout_pulsewidth_us(obj, seconds * 1000000.0f); } void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { pwmout_pulsewidth_us(obj, ms * 1000); } void pwmout_pulsewidth_us(pwmout_t* obj, int us) { float value = (float)us / (float)obj->period; pwmout_write(obj, value); } #endif
After the above was edited as shown then all PWM periods selected were correctly resolved
HAL Clocks are as follows:- PCLK1=42000000 PCLK2=84000000 HCLK=84000000
Kind Regards
Martin
This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies. If you are not happy with the use of these cookies, please review our Cookie Policy to learn how they can be disabled. By disabling cookies, some features of the site will not work.
Thanks for reporting and even providing fix. Can you report t his to https://github.com/mbedmicro/mbed/issues ? You can send PR fixing the problem.
I believe this issue tracker will be closed soon, as github issues is the place to report issues in mbed SDK.