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Hello, i want to make a 1 us interrupt timer in for my stm32f103 in timer 2, i could make 10 us n 5 us, but in lower than that its not working truely! what should i do?!
/* TIM2 init function */ static void MX_TIM2_Init(void) { TIM_ClockConfigTypeDef sClockSourceConfig; TIM_MasterConfigTypeDef sMasterConfig; htim2.Instance = TIM2; htim2.Init.Prescaler = 0; htim2.Init.CounterMode = TIM_COUNTERMODE_UP; htim2.Init.Period = 359; htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1; htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE; if (HAL_TIM_Base_Init(&htim2) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL; if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET; sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE; if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } }
it's workin with this for 5 us.
void SystemClock_Config(void) { RCC_OscInitTypeDef RCC_OscInitStruct; RCC_ClkInitTypeDef RCC_ClkInitStruct; /**Initializes the CPU, AHB and APB busses clocks */ RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE; RCC_OscInitStruct.HSEState = RCC_HSE_ON; RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1; RCC_OscInitStruct.HSIState = RCC_HSI_ON; RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON; RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE; RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL6; if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } /**Initializes the CPU, AHB and APB busses clocks */ RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2; RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK; RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2; RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1; if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } /**Configure the Systick interrupt time */ HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000); /**Configure the Systick */ HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK); /* SysTick_IRQn interrupt configuration */ HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0); } /* TIM2 init function */ static void MX_TIM2_Init(void) { TIM_ClockConfigTypeDef sClockSourceConfig; TIM_MasterConfigTypeDef sMasterConfig; htim2.Instance = TIM2; htim2.Init.Prescaler = 0; htim2.Init.CounterMode = TIM_COUNTERMODE_UP; htim2.Init.Period = 71; htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1; htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE; if (HAL_TIM_Base_Init(&htim2) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL; if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET; sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE; if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK) { _Error_Handler(__FILE__, __LINE__); } }
So is 1us realistic?
yes, i need to make a counter to count every 1 us, to detect a receiving frequency.
That wasn't the question!
sorry, what did you mean?
If I want to travel at 125mph, it is not realistic to expect to be able to do that on a bicycle.
Given your clock setup, the timer functionality, how fast your code executes, etc - is it realistic to expect to get 1us? Or is that just too fast to be realistic.
You do the maths ...
Again, this has little or nothing to do with Keil or ARM - it is down to the specifics of the ST chip.
I expect to get 1us,
i'm using stm32f103rbt6, and frequency is 72 mhz, Does this "ST" chip meet my expectations?
MohsenJanlou said:I expect to get 1us,
And how do arrive at that expectation? How did you check you haven't reached it?
Please note that looking at the input state every microsecond in an interrupt handler is hardly the optimal way of measuring a frequency at that input. That's what timers have input capture modes (and corresponding input pins) for.
No because your expectations are unrealistic and unattainable. It is akin to driving 1000 KM and every metre you travel a kid in the back seat asks if you're there yet, and wants to use the bathroom. Is it realistic to stop 1,000,000 times?
The TIM have methods to a) count pulses over a given observation window, or b) measure the time between the edges of the signals