Add MSP support for gyro_cal_on_first_arm

[haslinghuis]

• Fixes Add gyro_cal_on_first_arm betaflight-configurator#102
• Configurator PR: Add support for gyro_cal_on_first_arm betaflight-configurator#3938
• Support for disarm_kill_switch was removed in remove setting which disallow disarming on throttle above low #5073

[github-actions]

Do you want to test this code? You can flash it directly from Betaflight Configurator:

• Simply put #13626 (this pull request number) in the Select commit field of the Configurator firmware flasher tab (you need to Enable expert mode, Show release candidates and Development).

WARNING: It may be unstable. Use only for testing!

[McGiverGim]

I suppose now the comment is not necessary. Someone knows what was the reserved for?

[McGiverGim]

It seems it was for the disarm_kill_switch 45a6588

It's a good idea to reuse old MSP fields?

[haslinghuis]

@McGiverGim the parameter was removed in firmware 3.x as configurator only supports firmware 4.x so we can reuse safely.

[McGiverGim]

The reason of not reusing, was that third party tools can talk with the FC, not only the Configurator. If we don't plan to let this, no problem to reusing it.

[haslinghuis]

This was removed in 2018 so don't think it would have impact on 3d party tools.

[blckmn]

I'm not sure on this one. Why reuse? Configurator is not the only tool using msp.

[haslinghuis]

Happy to add a new parameter to the message. But as this was removed six years ago don't think it would be used anymore.

[blckmn]

Happy to add a new parameter to the message. But as this was removed six years ago don't think it would be used anymore.

The issue is we don't know what's out there (OSDs use MSP). And breaking this interface would have unpredictable results.

[ctzsnooze]

The PR itself looks fine.
Can I ask one question? Does enabling gyro cal on first arm delay arming until the calibration is complete? I’ve been concerned that if it did not delay arming, then the motors might shake the quad at the time the calibration is being performed.

[nerdCopter]

@ctzsnooze , this PR only add MSP to already existing routines,

i did not deep dive, but i found this: cleanflight/cleanflight#427 which alludes wait-for-arming.

[haslinghuis]

We use

betaflight/src/main/fc/core.c

Lines 183 to 196 in e602243

	static bool isCalibrating(void)
	{
	return (sensors(SENSOR_GYRO) && !gyroIsCalibrationComplete())
	#ifdef USE_ACC
	|| (sensors(SENSOR_ACC) && !accIsCalibrationComplete())
	#endif
	#ifdef USE_BARO
	|| (sensors(SENSOR_BARO) && !baroIsCalibrated())
	#endif
	#ifdef USE_MAG
	|| (sensors(SENSOR_MAG) && !compassIsCalibrationComplete())
	#endif
	;
	}

betaflight/src/main/fc/core.c

Lines 334 to 338 in e602243

	if (isCalibrating()) {
	setArmingDisabled(ARMING_DISABLED_CALIBRATING);
	} else {
	unsetArmingDisabled(ARMING_DISABLED_CALIBRATING);
	}