MPL3115A2,Dose I2C need an external pull up voltage？or it has been pulled up inside by VDDIO？And can you give an advise for pull up resistance？
Yes, external pull ups should be applied to I2C lines for MPL3115. Suggested value is 4.7k.
Please refer to FRDMSTBC-P3115-SCH for a reference connection setup of MPL3115.
Ok ，thank you。 What the function of VDDIO？
VDD is the main power supply for all internal analog and digital functional blocks.
VDDIO is a separate power supply pin used for the supply of the I2C digital communication interface.
So VDDIO sets the interface voltage level for the MPL3115A2 and your MCU. For single-supply operation, VDDIO can be the same as the main supply VDD. In a dual-supply applications, however, VDDIO can differ from VDD to accommodate the desired interface voltage.
Let us know if you have any other questions.
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