calibrate.py

from tests import *
import tests
import pickle

def calibrate():
    # Set up test system.
    setup()

    # Have user disconnect TARGET-C cable so we can power it without a load.
    # Using TARGET-C because it won't power up the EUT if they get it wrong.
    request("disconnect TARGET-C cable from EUT")
    connect_boost_supply_to('TARGET-C')

    # Power TARGET-C at 5V and calibrate lower range.
    with group("Calibrating low range"):
        set_boost_supply(5.0, 0.1)
        # Boost converter needs a moment to stabilise on first startup.
        sleep(0.1)
        scale_low = 5.0 / test_vbus('TARGET-C', Range(4.9, 5.1))
        item(f"Calibration factor: {info(scale_low)}")

    with group("Calibrating current offset"):
        current_offset = test_boost_current(Range(0, 0.15))
        item(f"Offset: {info(current_offset)}")

    # Increase voltage to 15V and repeat.
    with group("Calibrating high range"):
        set_boost_supply(15.0, 0.1)
        scale_high = 15.0 / test_vbus('TARGET-C', Range(14.5, 15.5))
        item(f"Calibration factor: {info(scale_high)}")

    # Write out calibration.
    calibration = dict(
        greatfet_serial=state.gf.serial_number(),
        voltage_scale_lower=scale_low,
        voltage_scale_upper=scale_high,
        current_offset=current_offset,
    )
    pickle.dump(calibration, open('calibration.dat', 'wb'))

if __name__ == "__main__":
    try:
        with error_conversion():
            calibrate()
            ok("Calibration complete")
    except CynthionTestError as error:
        fail(error)
    reset()