MMA8451Q What to do after unexpected MCU reset?

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MMA8451Q What to do after unexpected MCU reset?

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mma8451q
Contributor I

MMA8451Q.

What to do after unexpected MCU reset, if i cant power reset of MMA8451Q?

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TomasVaverka
NXP TechSupport
NXP TechSupport

Pavel,

As the MMA8451Q does not have a reset pin, the only way to reset (clear) the I2C bus is to (temporarily) re-assign SCL as a general-purpose I/O pin and then issue clock pulses until the MMA8451Q releases SDA. This is also described in the UM10204 on page 20.

Regards,

Tomas


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TomasVaverka
NXP TechSupport
NXP TechSupport

Pavel,

You can set the RST bit in the CTRL_REG2 register (0x2B) to initiate a software reset. It resets all functional block registers and loads the respective internal registers with their default values. The reset mechanism can be enabled in both standby and active modes.


I hope this helps.


Regards,

Tomas

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mma8451q
Contributor I

Thank You, Thomas!

What if after an unexpected reset MCU hung I2C bus?

Some i2c devices for such cases there is a certain sequence of actions. Tell me, please

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TomasVaverka
NXP TechSupport
NXP TechSupport

Pavel,

As the MMA8451Q does not have a reset pin, the only way to reset (clear) the I2C bus is to (temporarily) re-assign SCL as a general-purpose I/O pin and then issue clock pulses until the MMA8451Q releases SDA. This is also described in the UM10204 on page 20.

Regards,

Tomas


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