MMA7260QT accelerometer; selecting sensitivity when using 5v

[soccer]

Hi, I am using a 5v microcontroller to power the MMA7260QT accelerometer. I want to change the default sensitivity from 6g and am confused by the following:

“Instead, the microcontroller I/O pin can emulate an open-drain or open-collector output by alternating between low output and high-impedance (input) states. Put another way, if you are using a 5 V microcontroller, you should make your sensitivity selection I/O lines inputs and rely upon the internal pull-ups on the GS1 and GS2 lines if you want them to be high. It is always safe for you to drive these lines low.”

Is there any way I can connect the GS1 and GS2 pins to the 3.3V pin? I have a six-conductor cable and just wanted to use the jumpers to change the sensitivity. But if they are connected to the Vcc and I am using 5v, is this impossible?

Thanks for any help or ideas.

[mike31416]

Hey,

The GS1 and GS2 lines have a pullups to the internal 3.3 VCC. If you want to use a jumper to select the GS inputs, then just either ground the GS line or let it float.

I soldered two pins to the two holes (ground) across from the GS1 and GS2 pins and use a shorting blocks (https://www.pololu.com/catalog/product/968) to select the gain.

Hope this helps,
Mike

[soccer]

Thanks, Mike! I think I was confusing Vcc with Vin; it seems like I should have no problem sending only 3.3V to the GS1 and GS2. (I was worrying about driving them high as I am using a 5V power supply, and the specs warned against this).

Thank you for your help!
-soccer