1700 - Power Manager II: How do I use the ispPAC-POWR1220's on-board ADC through the I2C port?
To use the ispPAC-POWR1220's on-chip ADC, you must perform the following steps (via I2C):
- Issue a start conversion command. This is a write to the ADC mux register (0x09) in which you specify the ADC's input channel and the attenuation factor. Performing a write to this register automatically starts the conversion.
- Wait for either (a) the ADC's 'DONE' bit to go high (bit 0 of register 0x07), or (b) 200us after sending the 'start conversion' command.
- Read out the low and high bytes of the ADC result from registers 0x07 and 0x08.
If you are operating your I2C bus at < 50kHz, we recommend that you do not rely on the 'DONE' bit and simply wait 200us.