Which header file do I need to include to resolve this issue?

[RCooke88]

I'm using the STM32L010 chip and am trying to write a routine to allow me to get a delay of 10uS. But when I try to add this:

/**

 * @brief This function provides a delay (in microseconds)

 * @param microseconds: delay in microseconds

 */

_STATIC_INLINE void DWT_Delay_us(volatile uint32_t microseconds)

{

 uint32_t clk_cycle_start = DWT->CYCCNT;

 /* Go to number of cycles for system */

 microseconds *= (HAL_RCC_GetHCLKFreq() / 1000000);

 /* Delay till end */

 while ((DWT->CYCCNT - clk_cycle_start) < microseconds);

}

to my header file I get this error:

../Core/Inc/dwt_stm32_delay.h: In function 'DWT_Delay_us':

../Core/Inc/dwt_stm32_delay.h:30:29: error: 'DWT' undeclared (first use in this function)

  30 | uint32_t clk_cycle_start = DWT->CYCCNT;

I guess I'm not INCLUDEing the proper header file. I added "#include "stm32l0xx_hal.h" but that didn't help.

Any ideas?

Thanks,

Richard

[Peter BENSCH · Accepted solution]

Welcome, @Community member​, to the community!

DWT stands for Data Watchpoint and Trace and is usually included in STM32 based on Cortex-M3, Cortex-M4/-M33 and Cortex-M7, but not in the Cortex-M0+ of the STM32L010.

Does it answer your question?

Regards

/Peter

[RCooke88]

Thanks Peter I guess that explains what I did wrong.

[Peter BENSCH]

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter