STM32F4 Discovery board - Keil 5 IDE with CubeMX: Tutorial 18 Timers - Input Capture

[@bernardmercier5984]

Hello, by far the best tutorials on STM32 peripherals! Thank you so much.

[@mutexembedded2206]

Cheers Bernard

[@sameenashaikh_29]

Hi, Finally a new video from you! Happy about it! Was waiting for this

[@cosmoalien12345]

Thanks , your videos have helped in many projects

[@sayo9394]

Great tutorial, the non-cube part of it was extremely useful, thank you. It would be great if we can access the code itself, maybe a github repo

[@mutexembedded2206]

Simon Ayoub I completely forgot to attach the src code here, I said I will do that in the video, thanks for the reminder Simon!

[@alexdex9439]

How can I perform input capture from the output of a comparator?

[@halukcakir5279]

When i compile, i am getting a error error: Description Resource Path Location Type invalid type argument of '->' (have 'TIM_HandleTypeDef' {aka 'struct '}) stm32g4xx_hal_tim.h /12_Input_Capture_G474_02/Drivers/STM32G4xx_HAL_Driver/Inc line 1551 C/C++ Problem Can you help me?

[@youngolutosin1658]

Thank you so much Yaqoob your video has really helped me alot and has improved the time it takes me to implement my project. I am working on an algorithm and wanted to test if the heart rate algorithm is efficient and accurate. I decided to use an analog heart pulse sensor, convert the value using 8 bits and the digital value will be fed to the a digital pin with timer input compare. Everytime there is a rising edge, the time will be logged and this will be viewed on oscilloscope and how many beats in one minute will be calculated. Kindly help me look into this approach or how can I implement this? Thank you.

[@thanhthonguyen6171]

hi, bro. I want to know maximum of the input frequency can be measured. I will use STM32F4 to measure input signal with frequency of about 30Mhz. Can it be measured? thank you!!!

[@mutexembedded2206]

Hi, Potentially.. I have not tried it yet. Give it a try yourself following all guidelines.

[@thanhthonguyen6171]

thank bro! I will come back when I find the results, cheer!!!

[@serdarbatkan1414]

Hello, How can we read( decode) PPm signal ?

[@abdulkhan-rd8lu]

great video thanks for sharing, i got a question can we use hrtim(high resolution timer) for input capture and get psec resolution???????

[@mutexembedded2206]

Hi Abdul, I don't know I am afraid, I haven't tried it with HRTIM before. I will be interested to know if you had a success with this.

[@abdulkhan-rd8lu]

Hi MR.MYaqoob' thanks for the reply the datasheet says resolution in p sec but i was only able to capture the input events twice the speed of timer a.b,c with HRTIM but not psec any help would be appreciated by the way i m using discover stm32f334c8

[@arifkhan-xs5nk]

can we display the value of countval on the lcd display

[@mutexembedded2206]

Yes, you can

[@ThinkElectronicCircuits]

Is it possible to measure the duration for which the pulse is High by Timer input capture?

[@mutexembedded2206]

Hi, Yes, you can do that. Need to start counter at rising edge and stop at falling, if you know when the pulse will start, it is easy such as with Ultrasonic module. Hope this helps.

[@MO_Ventures710]

HI Yaqoob..I want to interface tcs3200 color sensor with STM32f746zg..Since the tcs3200 outputs a frequency based on the amount of light received i need some way to measure time. There is one output, which I connected to the input of as Input Capture.i am having some problems as i just started working on controllers.can you give me some hint or any kind of help to do this..thanks

[@mutexembedded2206]

Asim A Qayyum Hi Asim, You first need to know the frequency range of the output of your sensor (e.g. 1Khz to 50 khz) .. then configure an IC timer to calculate the time between two consecutive rising edge or falling edges,, and make the timer period long enough (e.g. 5 seconds), so that you start the IC timer for few seconds and get some measurement and stop the timer before the end of the 5 seconds to avoid overlap. Hope this helps

[@MO_Ventures710]

Hi Yaqoob. In CubeMx i set PF6(s0) PF7(s1) PF8(s2) PF9(s3) and TIM2 ch1 input capture as (out) of the sensor.frequncy for timer 2 i selected is 84Mhz with prescalar 83 which will bring it to 1mhz(i am not sure whether i should do this or not)I also enabled tim2 globle interrupt in nvic window.next i activated timer6 to measure time of 5s(timer f=84mhz,prescalar=41999 and counterperiod = 9999)..I have doubt about how to use these two timers inside the while loop, which HAL library functions to use here and how to use. CubeMX is the source code generator and IDE is Kiel5. following is my setting for output frequency scaling and filtertype outside the main function.if i am wrong please correct me. void TCSFREQ() { HAL_GPIO_WritePin(GPIOF, s0_Pin,GPIO_PIN_SET); HAL_GPIO_WritePin(GPIOF, s1_Pin,GPIO_PIN_RESET); } void TCSRED() { HAL_GPIO_WritePin(GPIOF, s2_Pin,GPIO_PIN_RESET); HAL_GPIO_WritePin(GPIOF, s3_Pin,GPIO_PIN_RESET); } void TCSBLUE() { HAL_GPIO_WritePin(GPIOF, s2_Pin,GPIO_PIN_RESET); HAL_GPIO_WritePin(GPIOF, s3_Pin,GPIO_PIN_SET); } void GREEN() { HAL_GPIO_WritePin(GPIOF, s2_Pin,GPIO_PIN_SET); HAL_GPIO_WritePin(GPIOF, s3_Pin,GPIO_PIN_SET); } void TCSCLEAR() { HAL_GPIO_WritePin(GPIOF, s2_Pin,GPIO_PIN_SET); HAL_GPIO_WritePin(GPIOF, s3_Pin,GPIO_PIN_RESET); }

[@mutexembedded2206]

Asim A Qayyum Hi Asim, If you are just trying to measure time period of the light sensor signal,, then one timer as IC will do the job. As I explained earlier, You need to set an input capture just like in my video above but with different prescalar and period.

[@rohitpatil4785]

Hello sir, I will try without cubemx Input capture code,but its showing following two errors, do you know why it happen? Please help me for this, .\Frequency Reading Wiithout Cube.axf: Error: L6218E: Undefined symbol HAL_DMA_Abort (referred from stm32f4xx_hal_tim.o). .\Frequency Reading Wiithout Cube.axf: Error: L6218E: Undefined symbol HAL_DMA_Start_IT (referred from stm32f4xx_hal_tim.o). Thanks

[@rohitpatil4785]

Could you please send me your project file?

[@pablogonzalezvizuete140]

Hi Mohamed. Thank you for your videos in general, I'm learning to program microcontrolers with them! Very instructive that you include with and without Cube. I'm trying the code without Cube and I don't know why the program doesn't enter HAL_TIM_IC_CaptureCallback. Could you please send the link for your code? Thanks!

[@mutexembedded2206]

Pablo González Vizuete Hi Pablo, Good to know that you're finding them helpful.. Yes, will do. I will attach the main.c shortly. Good luck

[@mutexembedded2206]

Just updated it,, now you should be able to see the main.c file down in the description. Cheers

[@pablogonzalezvizuete140]

Thank you! I finally found out my error (a letter missing in my code in the name of SysTick_Handler :)) Cheers

[@vikrantthakur7482]

My system hangs completely when I use an input capture button method using STM Discovery whenever a high signal is given,it completely hangs

[@mutexembedded2206]

Hi, Do you have a HAL_Delay inside the TIM_IC callback function ?

[@vikrantthakur7482]

@@mutexembedded2206 No actually, I just found out by mistake I commented out interrupt handler. Now it's working fine thanks for your video and help Yaqoob. I am trying to read the duration of the digital pulse produced by my heartbeat sensor(in place of the button).

[@mutexembedded2206]

@@vikrantthakur7482 Great

[@youngolutosin1658]

@@vikrantthakur7482 I wanted to achieve the same thing too: here is my approach, the output of my digital sensor will be connected to digital input with input compare enabled and using rising edge and logging the time for every rising edge just like the case of button but here the rising edge will be generated by the digital sensor when there is heart pulse. I will log this using oscilloscope and will calculate low how many beats I have in 60 seconds. Kindly share how you implemented yours mine was just a thought approach. I have not implemented it yet. Thank you Yaqoob and Thakur.

[@IPridek]

How i can start learning these parts of the MCU , some reference or book? Thanks

[@paulopecegueiro1694]

Mastering STM32 is a good one to start

[@michaelcollins399]

So how exactly does the prescaler value correlate with the actual time passed? thanks

[@mutexembedded2206]

Michael Collins Hi, Prescalar will scale CNT clock speed say to 1KHz (i.e. T = 1ms). Thus each Input Capture Counter correspond to 1ms. So for 230 IC value = 230ms between start and Rising edge detection.

[@michaelcollins399]

How will changing the prescaler value to 16000, scale the CNT clock speed to 1kHz? Thanks for the swift reply and I really enjoy your very well made videos.

[@mutexembedded2206]

Michael Collins Because TIM2 is driven by APB1 Clock whose frequency is 16MHz.

[@amitchautmal]

Sir please demonstrate timer in one pulse mode . Using stm32f103 .thanks

[@javib8970]

for anyone having problems wih the HAL macros this works: void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim) { /* Prevent unused argument(s) compilation warning */ UNUSED(htim); /* NOTE : This function Should not be modified, when the callback is needed, the __HAL_TIM_IC_CaptureCallback could be implemented in the user file */ if(htim->Instance == TIM2){ inputCaptureVal = htim2.Instance->CNT; htim2.Instance->CNT=0; } }

[@VarunKumar-gx7sd]

Hi Do you have direct register access code for basic timer interrupt??

[@VarunKumar-gx7sd]

As I am new to the board want to learn from base

[@bkn6362]

Writing directly into the library functions is just a no-no.

[@vladik8843]

Be careful when using __HAL_TIM_GET_COUNTER(). ITs expecting &htim not htim.

[@aye685]

Hello , How can I count the pulse numbers of PWM signal ?

[@mutexembedded2206]

Hi mate, Use ETR TIM input mode, I haven't made a tutorial on this yet. Will be good one for coming tutorials. Wish I have spare time.