How much is the current consumption of LIS3DH in FIFO mode?

[Kevin Brown]

Posted on February 17, 2018 at 12:00

I am seeking about the average current consumption of LIS3DH in FIFO mode (@10Hz). In its datasheet the current consumption in Low power mode, Normal mode, and High resolution mode is said to be 3~4 uA. 

I used the official driver and achieved to these values. As its driver is incomplete in FIFO mode, I could not test this device in FIFO mode. 

Could you please tell me about the current consumption in FIFO mode? 

Additionally, Could you share any sample code for driving the LIS3DH in FIFO mode ?

#fifo #current-consumption #lis3dh

[Miroslav BATEK]

Posted on February 20, 2018 at 14:19

The enabled FIFO doesn't have significant influence on the current consumption.

The FIFO has several modes, they are were very well described in the application node

http://www.st.com/resource/en/application_note/cd00290365.pdf

. Please check the chapter 9.

[Kevin Brown]

Posted on February 24, 2018 at 09:18

The problem is that I tried to read the FIFO in burst using TI CC2640 microcontroller over I2C. But reading in burst mode is unsuccessful (I have done this with Accelerometer sensors from Bosch and Invensense successfully).

I can only read FIFO buffer of LIS3DH byte-by-byte. In this way it takes about 50 ms to read the whole FIFO buffer which consumes much more power in compare to reading the accelerometer without FIFO. So reading FIFO buffer byte-by-byte is useless.

[Miroslav BATEK]

Posted on February 24, 2018 at 11:11

Unfortunately you didn't specify why the burts mode reading is unsuccessful, but I suppose you din't set the MSB bit of the register address.

In order to read multiple bytes, it is necessary to assert the most significant bit of the sub-address field.

Please check chapter 6.1.1 in the

http://www.st.com/content/ccc/resource/technical/document/datasheet/3c/ae/50/85/d6/b1/46/fe/CD00274221.pdf/files/CD00274221.pdf/jcr:content/translations/en.CD00274221.pdf

.