FXAS21002 (gyro) state diagram problem

[harrivanhala]

This may sound a stupid logical deadlock but I ask anyway:

FXAS21002 datasheet (Rev2.0, 2/2015) shows a transition diagram in Figure 15 on page 23.

According to the diagram: when the sensor is in the Active mode it can be directed to the Ready or the Standby mode by writing certain bits to the CTRL_REG1. The register description in chapter 6.15, page 42, clearly states that writing to CTRL_REG1 is allowed only in Standby or Ready mode, not in Active mode. Does this actually mean that the output data may be corrupted but the transition to the Ready or the Standby will take place anyway ie. the mode will be changed?

Best regards (and sorry for using bandwidth)

Harri Vanhala

[TomasVaverka]

Hi Harri,

The note in chapter 6.15 actually intends to say that the FXAS21002 should be either in the Standby or Ready mode to change the output data rate (DR[2:0] bits). Otherwise, accuracy of the output data is not guaranteed. So it is recommended to use something like this:

// Ready mode

IIC_RegWrite(CTRL_REG1, IIC_RegRead(CTRL_REG1) & 0b11111101);

// Change the ODR

IIC_RegWrite(CTRL_REG1, IIC_RegRead(CTRL_REG1) | 0b000xxx01);

// Active mode again

IIC_RegWrite(CTRL_REG1, IIC_RegRead(CTRL_REG1) | 0b00000011);

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct". Thank you.