PWM pins on STM32F072CB

Posted on October 12, 2016 at 13:15

Hi saraf.akshat, 

To let other community users helping you, try to provide more details about the hardware that you are using, if any external setup is established , and your code or part of it (Timer configuration for example).

I recommend that you run the ready-to-use example ''TIM_PWMOutput'' in the

http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software/stm32cubef0.html

library package at this path : STM32Cube_FW_F0_V1.6.0\Projects\STM32F072RB-Nucleo\Examples\TIM\TIM_PWMOutput

Try to figure out what you have missed comparing with your own code (TIM2 is used in the example, replace it with TIM3)

-Hannibal-

Posted on October 12, 2016 at 14:06

Hi Hannibal,

Thanks for you response.

Actually I am using mbed IDE and compiler for the development purpose.

I have attached a sample PWM sample code, reference board is selected as NUCLEO-F072RB. Please check that and help me.

________________

Attachments :

pwm_sample.txt : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0rn&d=%2Fa%2F0X0000000bhQ%2FSRUeTagP_C2oMEBJ3TvhvZYYwDqc2zkbsyMSwpecfDE&asPdf=false

Posted on October 12, 2016 at 14:44

And can you toggle that pin manually, if you set it as a plain output?

JW

Posted on October 12, 2016 at 15:28

Hi Jan,

Yes, when i am configuring these pins as DigitalOut, these are working properly.

Posted on October 12, 2016 at 19:18

Hi saraf.akshat,

I see that you have already posted in the mbed communicty for this subject. I notify our mbed developper to investigate, and I will come back to you. 

-Hannibal-

Posted on October 12, 2016 at 19:20

According to the manual they are using PC7 (D9) for TIM3_CH2 and PB4 (D5) for TIM3_CH1

Now while I might expect getting the PWM out of PB5 (D4) TIM3_CH2 is possible, you'd likely have to dig back into the mbed pin definition stuff related to the board itself for that to happen.

Posted on October 13, 2016 at 07:07

Hi Hannibal,

Thank you so much for your support.

Posted on October 13, 2016 at 11:22

Hi saraf.akshat,

We confirme the bug. A pull request is greated in the Github for fixing it at this

https://github.com/ARMmbed/mbed-os/pull/3008

Meanwhile, you can use the mbed-dev source in the mbed IDE and correct it in PeripheralPins.c as follow :

replace:

{PB_5, PWM_3, STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3, 1, 0)},TIM3_CH2 
by: 
{PB_5, PWM_3, STM_PIN_DATA_EXT(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3, 2, 0)}, TIM3_CH2

I gave you the same response on your mbed thread.

-Hannibal-

Posted on October 13, 2016 at 12:14

Hi Hannibal,

Thank for the support.

I have gone through the mbed library source. I found the PeripheralPins.c file, but the PWM pin definition looks like this:

const PinMap PinMap_PWM[] = {

//  {PA_1,  PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH2

    {PA_1,  PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_TIM15)}, // TIM15_CH1N

    {PA_2,  PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM15)}, // TIM15_CH1

//  {PA_2,  PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH3

    {PA_3,  PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM15)}, // TIM15_CH2

//  {PA_3,  PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH4

    {PA_4,  PWM_14, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF4_TIM14)}, // TIM14_CH1

//  {PA_6,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH1

    {PA_6,  PWM_16, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_TIM16)}, // TIM16_CH1

//  {PA_7,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH2

//  {PA_7,  PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH1N

//  {PA_7,  PWM_14, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF4_TIM14)}, // TIM14_CH1

    {PA_7,  PWM_17, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_TIM17)}, // TIM17_CH1

    {PA_8,  PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH1

    {PA_9,  PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH2

    {PA_10, PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH3

    {PA_11, PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH4

    {PB_0,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH3

//  {PB_0,  PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH2N

//  {PB_1,  PWM_14, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM14)}, // TIM14_CH1

    {PB_1,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH4

//  {PB_1,  PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH3N

//  {PB_3,  PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH2

    {PB_4,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH1

    {PB_5,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM3)},  // TIM3_CH2

    {PB_6,  PWM_16, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM16)}, // TIM16_CH1N

    {PB_7,  PWM_17, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM17)}, // TIM17_CH1N

    {PB_8,  PWM_16, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM16)}, // TIM16_CH1

    {PB_9,  PWM_17, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM17)}, // TIM17_CH1

//  {PB_10, PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH3

//  {PB_11, PWM_2,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM2)},  // TIM2_CH4

    {PB_13, PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH1N

    {PB_14, PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM15)}, // TIM15_CH1

//  {PB_14, PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH2N

    {PB_15, PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF1_TIM15)}, // TIM15_CH2

//  {PB_15, PWM_1,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF2_TIM1)},  // TIM1_CH3N

//  {PB_15, PWM_15, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF3_TIM15)}, // TIM15_CH1N

    {PC_6,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM3)},  // TIM3_CH1

    {PC_7,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM3)},  // TIM3_CH2

    {PC_8,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM3)},  // TIM3_CH3

    {PC_9,  PWM_3,  STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF0_TIM3)},  // TIM3_CH4

    {NC,    NC,    0}

};

I think there is no need or provision to change the Timer3 channels in definition.

Should i need to look in the other source.

Posted on October 14, 2016 at 10:25

Hi saraf.akshat, 

This is the link of the file to modify:

https://developer.mbed.org/users/mbed_official/code/mbed-dev/file/21d94c44109e/targets/hal/TARGET_STM/TARGET_STM32F0/TARGET_NUCLEO_F072RB/PeripheralPins.c

-Hannibal-