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a 32-bit global variable uwTick is defined. We basically configured the timer to count once every microsecond, so we’ll keep counting from zero until we reach that number in one microsecond intervals. The HAL library is very simple to implement the delay function. It’s just there to count and waste time, and create our delay effect. The reason the while loop is terminated with a semicolon instead of brackets like while loops always do, is because there’s nothing to do in it. Then after generating the code, add this function to your program void Delay_us (uint16_t n)Įasy, right? But what does this function do? In the first line the counter register is set to 0, then in the next line there’s a while loop that doesn’t end until the count register reaches the “n”. Simple busy waiting for use before clocks/timers are initialized.
STM32 SIMPLE DELAY HOW TO
The second part includes a step-by-step tutorial on how to set up Keil uVision, create a project and write code to blink the on-board LED on the NUCLEO STM32F103RB. Delay is a function thats block the cpu for certain of time and can’t move beyond this point until the delay time is. stm32: Add delay after enabling peripheral clock chromiumos/platform/ec : master. In the first part of this post, we will take a look at STM32 microcontrollers, their history and the families of microprocessors and boards. Systick timer is the system tick timer, a 24-bit. Generally in STM32+UCOS systems, Systick is used to make the UCOS heartbeat clock. If you’re confused about this procedure, check out our timer tutorial. For example, in UCOS, time-sharing reuse requires a minimum time stamp. This is due to the fact that the counting period of a timer comes from the formula: counting_freq = bus_freq / (Prescaler+1). For example if you’re clocking TIM1 with a 72MHz clock, set the prescaler to 71, so that timer would count up every microsecond. In STM32Cube, set the “Prescaler” value to one less than your bus clock in MHz. So the HALDELAY gets stucked in the endless loop do.while, because the systick isn't counting. If you call the HALDELAY in the interrupt that has greater priority, then systick counting is stopped.
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Then set the clock of your microcontroller and be attentive to the APB1/2 Timer Clocks in the clock tree. When you use a HALDELAY you have to keep in mind that the counting is done in the interrupt routine SysTick.
STM32 SIMPLE DELAY MANUAL
You can open the reference manual of your microcontroller, check the “memory map” and try to see which bus it is. First of all, you should find out whether your timer of choice is connected to the APB1 or APB2 bus. For example I decide to use TIM1 (timer 1). We’ll have to use one of our timer peripherals to achieve this aim. But what if that was not enough and you need to go smaller? Certain things do go on while the delay() function is controlling the STM32 chip, however, because the delay function does not disable interrupts. HAL has a very nice function named HAL_Delay(n) that can generate a delay of n milliseconds.