How many FIFO words with high compression (3xC) can be sent in a row by the IMU when the Timestamp, Accelerometer and Gyroscope FIFO buffering is enabled?

[BDiva.1]

LSM3DSO IMU: How many words with high compression (3xC) [each XL or GY] can be sent in a row by IMU? I suspect not more than twice in a row. For example:

...

-GY 3xC

-Timestamp

-GY 3xC

or

...

-XL 3xC

Timestamp

-XL 3xC

In other words, this case is not possible:

...

GY 3xC

Timestamp

GY 3xC

Timestamp

GY 3xC

...

Am I right?

[Eleon BORLINI]

Hi @BDiva.1​ ,

as reported in the application note AN5192, p.107:

FIFO compression supports three different levels of compression:

• NC, not compressed, if the difference between the actual and previous data is higher than 128 LSB: one sensor sample is stored in one FIFO word;

• 2xC, low compression, if the difference between the actual and previous data between 16 and 128 LSB: two sensor samples are stored in one FIFO word; 

• 3xC, high compression, if the difference between the actual and previous data is less than 16 LSB: three sensor samples are stored in one FIFO word.

So you should be able to store up to 3 sample sin a single FIFO word... please check also the answer to your other post if it can be of some help.

-Eleon

[BDiva.1]

Sorry you have not answered my question.

[Eleon BORLINI]

Hi @BDiva.1​ ,

is this question related to this other one?

-Eleon