lpi2c with powermode switch

[tbtbtbt]

Hello,

I am working on a project that uses the powermode_switch demo app with lpi2c communication. The problem I have is that whenever the project enters low power mode, the clock that lpic2 uses gets turned off and so the code gets stucks in the I2C transfer function. I would like to know what’s the best way to handle this. The I2C communication uses PLL3, so I was thinking of just removing the part of the low power mode that turns off PLL3, is this a good method? 

I am working on rt 1020 board. Using i2c1. 

[kerryzhou · Accepted solution]

Hi @tbtbtbt ,

   You need to check your used low power mode, whether the I2C is working and the I2C module clock is working or not, this is very important, otherwise you will meet issues.

  From the RT1020 reference, you can find:

Please also check, the following table in the RM:

So, you may need to use the OSC as the clock source, as the PLL3 is powered down, and you also need to clear MCR[DOZEN] bit in LPI2C module.

Wish it helps you!

Best Regards,

Kerry

[tbtbtbt]

Thank you for your help!