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MSP430F5419A: i2c pins floating during system sleep

Genius 10130 points

Replies: 1

Views: 55

Part Number: MSP430F5419A

Champs,

in a customer's system there are two 3.3V rails: 3v3 and 3v3_aux. The 3v3_aux powers the MCU and is always on while the 3v3 goes down during system's sleep. The MCU remains active at all times. The USCI pins in I2C slave mode are connected to PCA9515A buffers which are powered from 3v3 meaning that in sleep mode the buffers are off and the USCI pins are left floating. There is no i2c communications during sleep mode. Will this be a problem for the MCU when the system comes out of sleep?

thanks

Michael

  • Hi Michael,

    this depends on whether this will generate signal transitions on the I2C lines. If yes, this will definitely result in issues. The customer needs to take care of having defined conditions on the I2C interface during shut down of the external drivers. This is probably impossible, as this would mean keeping the signals pulled up, while the drivers are of, which would most probably result in short cuts.

    Without knowing the details from my perspective just a detection of the shut down of the 3V3 system, shutting down I2C as well and restarting it after return of the supply.

    Best regards

    Peter

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