Can a measurement on the K22 be done with the Vbus at 3.3V as is required by MFi? There are actually two power modes required:
- Low Power mode: the device is not running an audio app, has told the accessory to reduce current draw below 10mA & enter the zero bandwidth configuration, meaning that the device is still sending USB data frames & the accessory should be able to rapidly wake up when the relevant wake command is given.
- High Power mode: the device is now running an audio app & streaming audio data. The accessory must draw less than 100mA. The measurement in this mode is complicated, but I'll just boil it down to the bottom line that we need the MCU to come in at about 30mA or less here to make our system compliant.
Has Freescale measured the K22 for MFi applications? Can it meet the above requirements? Ideally do you have a demo app I can run on the FRDM-K22F to measure the two scenarios above to determine if the K22 is compliant for power consumption?