Microseconds delay lib based on DWT for STM32 or whatever ARM supporting it.
Just include dwt_delay.h
in your project, call DWT_Init()
and then use delays as needed.
Depending on MCU used, you may need to include another header file (with MCU peripherals defines) in dwt_delay.h
.
The stm32f1xx.h
is included by default, allowing STM32F1xx to start out of the box.
If you don't use STM32 MCU or CubeMX, read a section at the end.
Functions are named as DWT_* to be HAL-alike. Feel free to do whatever you like with this lib, change names, indents, coding style, use it in LHC firmware.
/* main.c */
#include "dwt_delay.h"
void main (void)
{
// Init section of your code
DWT_Init();
while(1) {
// Delay for 42us
DWT_Delay(42);
}
}
Unfortunately, these are not supported, since cores have no access to DWT. CMSIS library states:
Cortex-M0/0+/1 Core Debug Registers are only accessible over DAP and not via processor
You may want a delay function based on hardware timer instead.
I don't have any of these to check, but in theory they are supported.
Anyway you have to change CoreDebug
to DCB
, because CoreDebug
is deprecated in these cores.
Hence, init sequence should be something like:
DCB->DEMCR |= โDCB_DEMCR_TRCENA_Msk;
There's an option to try! Also suits those, who use STM32, but dont use HAL/LL libs.
Include a CMSIS header file according to your core in dwt_delay.c
and change SystemCoreClock
variable to whatever you probably have in the project representing clock frequency (in Hz).
Something like this:
// In dwt_delay.c
#include "dwt_delay.h"
#include "core_cm4.h" // CMSIS header
#define SystemCoreClock NameOfTheGlobalVariableInYourProject_or_AnotherDefine
// or at least
#define SystemCoreClock 48000000UL // Clock is 48Mhz
...
-
2018-01-06 This lib emerged.
-
2019-02-19 Overflow check added.
-
2019-03-26 Typo in definition fixed. Got back to short and simpler function.
-
2023-11-21 Now it is MIT License. Added warning for Cortex-M0/0+/1 and notes regarding other Cortex-M cores.