Crate tag_cal_write 

tag-cal-write: write an identity (no-op) magnetometer calibration.

Port of host/commandline/tag-cal-write.cc. Writes M' = A(M - V) with A = identity and V = 0, and a zero accelerometer offset. Several CompassTag-family state handlers refuse to start a run until at least one calibration entry is stored (“Device must be calibrated”), which a mass-erase reflash wipes; this unblocks power and lifecycle testing on a freshly reflashed board. Readings taken under it are NOT calibrated: run tag-cal or qtcalibrate before trusting compass output from the board.

Usage: tag-cal-write [-d] [-b BUS:DEVICE].

Exit status

0 when the constants were written; 1 if no base matches, the attach fails or WriteCalibration fails. Option errors exit 2 (clap).

Hardware side effects

The attach resets the tag. The firmware stores the constants as a new calibration entry, so the tag will then start a run with an uncalibrated compass; overwrite it with a real calibration before trusting the data.

Structs

Cli 🔒

write an identity (no-op) calibration constant set, to unblock a tag that refuses to start with “Device must be calibrated” after a mass-erase reflash – NOT a substitute for real calibration

Functions

identity_constants 🔒

Identity magnetometer constants and a zero accelerometer offset.

main 🔒

Attaches (resetting the tag) and writes identity_constants.