Hi all,
I'm using a MAG3110 on a board quite similar to the TI Sensortag, a cc2541 controlling the MAG via I2C, but without all other sensors (just the mag).
I would like to use the MAG only once in a while (say, every 10 minutes for a few seconds, to save battery), so I'm using the 20miliamp pins of the TI to control the power in and out of the MAG.
I manage to get results from the MAG up to the first shut down, after that it seems that the measurement stops. When I'm giving a continuous "1" signal through that pin I keep getting measurements.
What could be the problem?
Thank you very much in advance,
Eran
Hello Eran,
Is the IIC bus still active while you "turn off" the MAG3110?
Please take a look at the datasheet page 6, table 4, Absolute Maximum Ratings:
http://cache.freescale.com/files/sensors/doc/data_sheet/MAG3110.pdf
Input voltage on any control pin (SCL, SDA) --> -0.3 to VDDIO + 0.3
If the IIC bus is still active while VDDIO is a zero logic, unknown behavior might occur or even worst, permanent damage. Instead of suppress the supply voltage, I would rather recommend you to set the device status to STANDBY mode by setting the SYSMOD register (0x08) to 0x00.
In STANDBY mode the MAG3110 would only draw ~2uA.
Hope it helps!
Josh