LSM9DS1 on single SPI bus with other devices

[Tomas Hamouz]

Posted on February 15, 2018 at 15:35

We need to share one SPI bus with LSM9DS1 and other devices. The problem is that when the CS signal is inactive, the chip expect I2C communication on MOSI/SDA line. What happens if there is a communication with other SPI device and CS signal is inactive? Does the chip recognize it is not I2C communication and remains silent or it starts to meddle into?

I know the I2C interface can be disabled in the registers, but to disable it I first need to communicate with both  interfaces active.

Tomas

[Miroslav BATEK]

Posted on February 16, 2018 at 10:09

The LSM9DS1 should not interfere with other communication on SPI bus it the CS is inactive.

Nevertheless I think it is good practice to disable the I2C interface of LSM9DS1 (there are two register one for accelerometer and gyro and one for magnetometer) at the begging of your program.