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marlin "Not enough delay for BABYSTEPPING if specific DRV8825 stepper driver is used

There are several stepper drivers that can be used, each having some minimum step pulse duration requirements (e.g. for A4988 is 1uS, for DRV8825 is 1.9uS). Changing the delay to take a larger value, e.g. 2uS has no effect on the steppers that require a minimum that is less than the set value. Issue 1900: https://github.com/MarlinFirmware/Marlin/issues/1900 "

Bug fixed by commit 53be0f3399e

Type	BehaviorViolation
Config	"BABYSTEPPING && DELTA" (2nd degree)
Fix-in	code
Location	movement/

#include <util/delay.h> // http://download.savannah.gnu.org/releases/avr-libc/binary-releases/ for the util/delay library
#include <stdbool.h>
#include <stdio.h>

#define X_AXIS 0
#define Y_AXIS 1
#define Z_AXIS 2

#define X 0
#define Y 1
#define Z 2

void enable_x()
{
	printf("%s", "enabling x axis");
}

void enable_y()
{
	printf("%s", "enabling y axis");
}

void enable_z()
{
	printf("%s", "enabling z axis");
}

#ifdef BABYSTEPPING

  // MUST ONLY BE CALLED BY AN ISR,
  // No other ISR should ever interrupt this!

  void babystep(const uint8_t axis, const bool direction) {

    #define BABYSTEP_AXIS(axis, AXIS, INVERT) { \
        enable_## axis(); \
        uint8_t old_pin = AXIS; \
        /* more functions here */ \
        _delay_us(1U); \ 
        /* more functions here */ \
      }

    switch(axis) {

      case X_AXIS:
        BABYSTEP_AXIS(x, X, false);
        break;

      case Y_AXIS:
        BABYSTEP_AXIS(y, Y, false);
        break;
     
      case Z_AXIS: {

        #ifndef DELTA

          BABYSTEP_AXIS(z, Z, false);

        #else // DELTA

          enable_x();
          enable_y();
          enable_z();
          //setup new step
          //functions to move the x,y,z axis
          _delay_us(1U);
          //functions to move the x,y,z axis

        #endif

      } break;
     
      default: break;
    }
  }

#endif //BABYSTEPPING

int main(void) 
{
#ifdef BABYSTEPPING
    babystep(0, false);
#endif
    return 0;
}

diff --git a/simple/53be0f3.c b/simple/53be0f3.c
--- a/simple/53be0f3.c
+++ b/simple/53be0f3.c
@@ -36,7 +36,7 @@ void enable_z()
         enable_## axis(); \
         uint8_t old_pin = AXIS; \
         /* more functions here */ \
-        _delay_us(1U); \ 
+        delayMicroseconds(2); \ 
         /* more functions here */ \
       }
 
@@ -63,7 +63,7 @@ void enable_z()
           enable_z();
           //setup new step
           //functions to move the x,y,z axis
-          _delay_us(1U);
+          delayMicroseconds(2);
           //functions to move the x,y,z axis
 
         #endif

#include <util/delay.h> // http://download.savannah.gnu.org/releases/avr-libc/binary-releases/ for the util/delay library
#include <stdbool.h>
#include <stdio.h>

#define X_AXIS 0
#define Y_AXIS 1
#define Z_AXIS 2

uint8_t axis = 0;

int main(void) 
{
#ifdef BABYSTEPPING
#define BABYSTEP_AXIS(axis, AXIS, INVERT) { \
        /* enable_## axis(); */ \
        uint8_t old_pin = AXIS; \
        /* more functions here */ \
        _delay_us(1U); \ 
        /* more functions here */ \
      }

    switch(axis) {

      case X_AXIS:
        printf("%s", "enabling x axis");
        break;

      case Y_AXIS:
        printf("%s", "enabling y axis");
        break;
     
      case Z_AXIS: {

        #ifndef DELTA

        printf("%s", "enabling y axis");
        
        #else // DELTA

          printf("%s", "enabling x axis");
          printf("%s", "enabling y axis");
          printf("%s", "enabling z axis");
          //setup new step
          //functions to move the x,y,z axis
        _delay_us(1U);
          //functions to move the x,y,z axis
        
        #endif
        break;
      } 
     
      default: break;
    }

#endif //BABYSTEPPING

    return 0;
}

. call stepper.cpp:1136:void babystep()
. 1138: #define BABYSTEP_AXIS(axis, AXIS, INVERT) { \
. ERROR 1143:  _delayUs(1U);
. 1148: switch(axis) {
.. 1158: case Z_AXIS: {
.. ERROR 1182: _delayUs(1U);