[Target] FOXEERF722V4 - MPU6000, ICM42688P

[nerdCopter]

• FOXEERF722V4 - created by @BeauBrewski (modified after the fact)
• MPU6000
• ICM42688P

closes #876

Co-authored-by: nerdCopter 56646290+nerdCopter@users.noreply.github.com

[nerdCopter]

• dang it, i duplicated in [Target] FOXEERF722V4 ICM42668P MPU6000 #922 -- initially failed, but a second might be working. @mokshfpv is testing HD version.
• i don't know if this original one was tested by anyone or not.

[nerdCopter]

@mokshfpv report:
✅ .hex Flash
✅ Gyro
✅ Accelerometer
✅ Motors
untested Onboard ADC
untested OSD (analog) (due to HD/djiO3 setup)
untested Smart Audio controls (OSD and CLI)
untested Alarm switch
no Barometer on FC
✅ Blackbox flash-chip
untested LED
untested GPS

[nerdCopter]

dev-talk, re #922:

• 922 did not have #define ENSURE_MPU_DATA_READY_IS_LOW
• 922 did have #define DEFAULT_FEATURES (FEATURE_OSD | FEATURE_TELEMETRY | FEATURE_AIRMODE | FEATURE_RX_SERIAL) and #define DEFAULT_RX_FEATURE FEATURE_RX_SERIAL
• 922 did not seem to have other major differences, other than baro/i2c.
• unsure why 922 failed

edits:

• 922's .mk had F7X5XG_TARGETS += $(TARGET), but this one has F7X2RE_TARGETS += $(TARGET) <-- this was the problem that made 922 fail

[nerdCopter]

closing this in favor of #922 since it was fixed and scripted conversion