Declaration is incompatible with iar arm
- #Declaration is incompatible with iar arm how to#
- #Declaration is incompatible with iar arm drivers#
#Declaration is incompatible with iar arm drivers#
The CMSIS drivers provide a function, SysTick_Config(), that is used to set up the systick event. It is a blinky that tests the system clock speeds. Something like this should probably be the first thing you run on a new board. It is soon apparent if the calculations are wrong. For this purpose, I like to just flash an LED once per second. The trick then is to proceed with the systick configuration and set up some test code that will tell you immediately if you have it right. Not only are magic numbers a Very Bad Thing in your code, if you make a mistake, the error can be hard to find.įortunately the peripheral drivers provide a handy way to get the current value of the HCLK and use it in your calculations without having to know what it is. You may think, at that stage, that you know what the clock frequency is but you should avoid referring to it by numerical value. In a typical standard project setup the startup code will call the SystemInit() function for you and, by the time your program gets control, the clocks are all set up and running. Specifically, they have a spreadsheet that can work out all the settings for you and generate the system_stm32f4xx.c file that makes it all happen. Perhaps the easiest way to do it is to use the tools from ST. Clock setup on the ARM cores is pretty involved. System Clock Frequencyīy far the hardest part of the whole process is determining the actual clock frequency of your processor. A version for the newer HAL drivers may follow later. The code makes use of the older Standard Peripheral Drivers. The example here uses the STM32F407VG found on the STM32F4 Discovery board.
If you make the interval something simple and obvious, like every millisecond, you also have access to an easy way to generate delays or time events with millisecond accuracy. It can look after user inputs, scheduling, sensor monitoring, real-time synchronisation and basic timing tasks.
#Declaration is incompatible with iar arm how to#
Here I will show you how to set it up on the STM32F4xx processors to generate an interrupt every millisecond.Ī steady background tick event is great for all kinds of systems. This timer is very useful for producing the main system event clock. The other variants, such as the M0 may not have one. The ARM cortex M4 and M3 processors all come with a systick timer that is part of the core.