Dear all,
I am working on a project with an L081KZ and want to count pulses with a frequency higher than the clock. In the post here (community.st.com/s/question/0D53W00001EyzG5SAJ/) I thankfully got the tip to use the LPTIM as it has an asynchronous feature.
Sadly I cant get the LPTIM to run at all with an external clock and would like your help. There must be a fundamental problem I am overlooking.
I apply a signal (quite slow with 1kHz and 3Vpp) onto PB5 / LPTIM but neither do I get a 1/20th of the signal (counting to 10 and 2 times because of the toggle-function) on PB3 / TOGGLE nor do I reach the breakpoints in “LPTIM1_IRQHandler�?. In “Instance�? → “CNT�? is always 0.
Looking at the “Low-power timer block diagram“ i get i want the „LPTIM_IN1„ as input and not the trigger so I don’t get constrains by the Mux. Do I need to specify anywhere that it is PB5 or is it implied as there is no other pin possible? Also I activated the interrupt checkbox NVIC.
I configured the LPTIM via the CubeIDE as shown in the image and tried the minimal code shown below.
I would really appreciate a hint on what I am missing or where my assumptions are wrong.
Best wishes
Tobias
#include "main.h"
LPTIM_HandleTypeDef hlptim1;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_LPTIM1_Init(void);
/* USER CODE BEGIN*/
void HAL_LPTIM_AutoReloadMatchCallback(LPTIM_HandleTypeDef *hlptim)
{
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_3);
}
/* USER CODE END*/
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_LPTIM1_Init();
/* USER CODE BEGIN*/
HAL_LPTIM_Counter_Start_IT(&hlptim1, 10);
/* USER CODE END*/
while (1)
{
}
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV16;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
PeriphClkInit.LptimClockSelection = RCC_LPTIM1CLKSOURCE_PCLK;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
}
static void MX_LPTIM1_Init(void)
{
hlptim1.Instance = LPTIM1;
hlptim1.Init.Clock.Source = LPTIM_CLOCKSOURCE_ULPTIM;
hlptim1.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;
hlptim1.Init.UltraLowPowerClock.Polarity = LPTIM_CLOCKPOLARITY_RISING;
hlptim1.Init.UltraLowPowerClock.SampleTime = LPTIM_CLOCKSAMPLETIME_DIRECTTRANSITION;
hlptim1.Init.Trigger.Source = LPTIM_TRIGSOURCE_SOFTWARE;
hlptim1.Init.OutputPolarity = LPTIM_OUTPUTPOLARITY_HIGH;
hlptim1.Init.UpdateMode = LPTIM_UPDATE_IMMEDIATE;
hlptim1.Init.CounterSource = LPTIM_COUNTERSOURCE_EXTERNAL;
if (HAL_LPTIM_Init(&hlptim1) != HAL_OK)
{
Error_Handler();
}
}
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
__HAL_RCC_GPIOB_CLK_ENABLE();
HAL_GPIO_WritePin(TOGGLE_GPIO_Port, TOGGLE_Pin, GPIO_PIN_RESET);
GPIO_InitStruct.Pin = TOGGLE_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(TOGGLE_GPIO_Port, &GPIO_InitStruct);
}
void Error_Handler(void)
{
__disable_irq();
while (1)
{
}
}
#ifdef USE_FULL_ASSERT
void assert_failed(uint8_t *file, uint32_t line)
{
}
#endif
1 ACCEPTED SOLUTION
Accepted Solutions
Dear @Community member ,
thank you again very much for your answer.
I hope the attached register is what you want? If not please be so kind and refer me to the specific part (I'm quite new to the STMverse and HAL especially). I didn't post the GPIO register because the pin cant be toggled if the LPTIM doesn't count up and the Callback isnt polled (breakpoint is not reached).
Best wishes
Tobias
