Configure stm32 timer as a counter of a RPM of a rolling gear

[medraouf]

good morning

i was trying for sometime now to configure stm32 timer as a counter to count the pulses in order to count the RPM of a rolling gear and then show it on a lcd screen, and no matter what i do or change in the code or the timer configuration, the number of pulses is always stuck at 0. can anyone please help me with it? i really need it for my studies. (by the way, i am using a proteus simulation to test it).

[AScha.3]

Hi,

how you get the pulses to the counter ?

You need select the ETRx as input to count external pulses. 

Or TIMxx input capture, to measure just one pulse-pulse timing and calculate speed then.

[medraouf]

@AScha.3 i already tried that...

[SofLit]

Hello @medraouf ,

As stated by @AScha.3 ETR is a serious candidate for your use case.

---

@medraouf wrote:

@AScha.3 i already tried that...

---

No one here can imagine what you did ..

You need to share your code to let community members to help you efficiently + your HW connections.

It could be an issue with your IO configuration or even with the timer itself ..

[medraouf]

#include "main.c"
#include "stm32f1xx.h"
#include "lcd8.h"

// Global variables to store pulse counts for each channel
volatile uint32_t channel1_count = 0;
volatile uint32_t channel2_count = 0;
volatile uint32_t channel3_count = 0;
volatile uint32_t channel4_count = 0;

// LCD configuration
#define LCD_PORT GPIOB
#define LCD_RS_PIN GPIO_PIN_0
#define LCD_EN_PIN GPIO_PIN_1
#define LCD_D0_PIN GPIO_PIN_2
#define LCD_D1_PIN GPIO_PIN_3
#define LCD_D2_PIN GPIO_PIN_4
#define LCD_D3_PIN GPIO_PIN_5
#define LCD_D4_PIN GPIO_PIN_6
#define LCD_D5_PIN GPIO_PIN_7
#define LCD_D6_PIN GPIO_PIN_8
#define LCD_D7_PIN GPIO_PIN_9

void TIM2_IRQHandler(void) {
    if (TIM2->SR & TIM_SR_CC1IF) {
        // Channel 1 capture event occurred
        channel1_count++;
    }
    if (TIM2->SR & TIM_SR_CC2IF) {
        // Channel 2 capture event occurred
        channel2_count++;
    }
    if (TIM2->SR & TIM_SR_CC3IF) {
        // Channel 3 capture event occurred
        channel3_count++;
    }
    if (TIM2->SR & TIM_SR_CC4IF) {
        // Channel 4 capture event occurred
        channel4_count++;
    }
    // Clear interrupt flags
    TIM2->SR = 0;
}
void TIM2_Init(void) {
    // Enable TIM2 clock
    RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;

    // Set TIM2 prescaler for 1 us resolution (assuming HCLK = 64MHz)
    TIM2->PSC = 64 - 1;

    // Configure TIM2 channels as input capture
    TIM2->CCMR1 |= (TIM_CCMR1_CC1S_0 | TIM_CCMR1_CC2S_0);
    TIM2->CCMR2 |= (TIM_CCMR2_CC3S_0 | TIM_CCMR2_CC4S_0);

    // Enable capture on both rising and falling edges
    TIM2->CCER |= (TIM_CCER_CC1P | TIM_CCER_CC1NP | TIM_CCER_CC2P | TIM_CCER_CC2NP |
                   TIM_CCER_CC3P | TIM_CCER_CC3NP); // Remove TIM_CCER_CC4P | TIM_CCER_CC4NP

    // Enable interrupts on capture events
    TIM2->DIER |= (TIM_DIER_CC1IE | TIM_DIER_CC2IE | TIM_DIER_CC3IE | TIM_DIER_CC4IE);

    // Enable TIM2 interrupts
    NVIC_EnableIRQ(TIM2_IRQn);

    // Enable TIM2
    TIM2->CR1 |= TIM_CR1_CEN;
}
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM2_Init(void);

int main(void)
{

  SystemClock_Config();


  MX_GPIO_Init();
  MX_TIM2_Init();

  lcdSetup(GPIOA, GPIO_PIN_8, GPIO_PIN_9, GPIO_PIN_0, GPIO_PIN_1, GPIO_PIN_2, GPIO_PIN_3, GPIO_PIN_4, GPIO_PIN_5, GPIO_PIN_6, GPIO_PIN_7);
     lcdInit();

     TIM2_Init();

     while (1) {
         // Display pulse counts on LCD
         lcdCommand(lcdClear); // Clear the LCD screen
         lcdSetCursor(0, 0);
         lcdString("Channel 1: ");
         lcdWriteInt("%d", channel1_count);
         lcdSetCursor(1, 0);
         lcdString("Channel 2: ");
         lcdWriteInt("%d", channel2_count);
         lcdSetCursor(2, 0);
         lcdString("Channel 3: ");
         lcdWriteInt("%d", channel3_count);
         lcdSetCursor(3, 0);
         lcdString("Channel 4: ");
         lcdWriteInt("%d", channel4_count);
         HAL_Delay(1000); // Update LCD every second
     }
 }

as you can see, the pulse number is stuck at 0 although i'm giving it a pulse signal from the the pulse generator. (note: i tried the same thing but without using the timer, only the interrupts of the stm32 and it worked, but there was a difference between the 4 channels, i guess because of the high frequency of the pulses, that's why i'm using the timer.)

[SofLit]

Frankly, I'm not in favor using this kind of simulation. Sometimes it does not work but when you switch to a real HW it does.

I recommend you to use a real HW.