Is this a bug or am I crazy?

[AdamDrefs]

So I'm doing some stuff requiring move planning in advance and I'm trying to use the fact that setSpeed...() and setAcceleration() don't take effect until the next move() call, but it seems like setSpeedInHz() is taking effect instantly anyways. The only change I make is moving the pause loop from before the new speed setting to after, and it changes the behavior. There's no call to move() or to SetSpeedAcceleration() that is changing positions either.

Hardware: RP2040, 2x TMC2209 stepper drivers.

For example it goes from this:

while(stepperA->isRunning() ||stepperB->isRunning()){}
stepperA->setSpeedInHz(speedA);
stepperB->setSpeedInHz(speedB);
stepperA->move(distA);
stepperB->move(distB);

to:

stepperA->setSpeedInHz(speedA);
stepperB->setSpeedInHz(speedB);
while(stepperA->isRunning() ||stepperB->isRunning()){}
stepperA->move(distA);
stepperB->move(distB);

I would like to be able to set the desired settings then apply them when necessary to avoid delays from processing time, and I can work around this, but I just want to know if anyone else has experienced this.

it says this on line 378 of FastAccelStepper.h:

 // Setting the speed can be done with the four `setSpeed...()` calls.
  // The new value will be used only after call of these functions:
  //
  // - `move()`
  // - `moveTo()`
  // - `runForward()`
  // - `runBackward()`
  // - `applySpeedAcceleration()`
  // - `moveByAcceleration()`
  //
  // Note: no update on `stopMove()`

[gin66]

The setSpeed/Acceleration are designed to only take effect, if one of the other commands are following. So my best bet is, that the while-loop is not actually waiting. Then the two versions are identical.

Please share some more code to better understand the issue.

[AdamDrefs]

Definitely not the while loop, since without it the whole thing acts completely different to either scenario. It's alright though because I don't need this anymore.