MMA8451 interrupt pin default state

[michaelburton]

Hi, I'm using an MMA8451 accelerometer to wake an MCU from deep sleep by pulling the reset line low momentarily when the device detects movement.

I understand the MMA8451 interrupt outputs can be configured to open drain, but that they are push-pull by default, which may interfere with the startup and operation of the MCU before I can configure them as open drain.

Can you please confirm what state the interrupt pins will be in (e.g. high, low, floating) when power is first applied?

Thanks,

Michael.

[darioarias]

Hi Michael,

As you stated, and as it is described in CTRL_REG3, PP_OD bit configures pin to push-pull or in open drain mode. The default value is 0 which corresponds to push-pull mode. Also the IPOL bit selects the polarity of the interrupt signal. When IPOL is '0' (Which is the default value) any interrupt event any interrupt event will signaled with a logical 0. This means that a power up this pin is push-pull and level high.

Regards,

Darío