2.1.28, initiation update to PXT v5.28.24 (#54)

docs/reference/input/calibrate-compass.md

@@ -0,0 +1,33 @@
+# Calibrate Compass
+
+Runs the compass calibration sequence.
+
+```sig
+input.calibrateCompass();
+```
+
+## Calibration
+
+The calibration will ask you to draw a circle or fill the LED screen by tilting the
+@boardname@.
+
+The compass calibration is stored in memory by the @boardname@, so next time you press the reset button or remove and replace the power the calibration will be remembered.
+
+When you flash a new program to your @boardname@ via USB, this memory is cleared so you will have to re-calibrate it.
+
+If you are calibrating or using the compass near metal, it might
+confuse the @boardname@.
+
+## Example
+
+This example runs the calibration when the user presses **A+B** buttons.
+
+```blocks
+input.onButtonPressed(Button.AB, () => {
+    input.calibrateCompass();
+})
+```
+
+## See also
+
+[compassHeading](/reference/input/compass-heading)