LSM303AGR, how to power off the accelerometer by software

Helmut Tschemernjak · ‎2016-07-19

Posted on July 19, 2016 at 21:08

I try to turn off the accelerometer by SPI commands to use only 1uA according to the spec. I have not found any SPI commands to turn it off to reduce power consumtion to about 1uA, everything I tried still needs about 150uA.

#lsm303agr

Miroslav BATEK · ‎2016-07-22

Posted on July 22, 2016 at 10:38

To minimize the power consumption accelerometer and magnetometer have to be set to power down mode ODR[3:0] = 0 in register CTRL_REG1_A (20h) and MD[1:0] = 2 in register CFG_REG_A_M (60h).

Best regards

Miroslav

Helmut Tschemernjak · ‎2016-07-26

Posted on July 26, 2016 at 14:40

I output CTRL_REG1_A to 0 and it still needs about 70uA. I cannot get this turned off to the 1uA specified in the

data sheet

. When I turn it into 10Hz low power it needs about 5uA as specified. It looks like powering off is not implemented.

Miroslav BATEK · ‎2016-08-02

Posted on August 02, 2016 at 12:08

Power off (power-down mode) is implemented.

In attachment you can find reference sensor setup, accelerometer is in power down mode, magnetometer is in idle mode.

In this configuration the current consumption is 2uA@2.5V which is in line with specification (see page 15 of LSM303AGR datasheet, line Idd_PD).

Best regards

Miroslav

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Attachments :

LSM303AGR.ucf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HzFI&d=%2Fa%2F0X0000000bKB%2FNguBPJ5H4zD7WjqyvTnxKHYxAFLlJIGk2RnUNrPF2mk&asPdf=false