Settling time after power on

Applications
1

I am trying to get angle data using SPI. It is specified that sensor will send correct angle data after 250us after powering on the sensor. But I have to wait for 200ms to get correct data after power on. I am using default FW window i.e. 5 and SPI data rate is 16MBPS. Also I am unable to chance FW window to 0.

2

Hello,

Can I ask which angle sensor you are using? Here are some general steps that you can go through while you provide the part number:

  1. Verify the power on sequence is correct and receives a clean input that align with the senor’s voltage and timing requirements. Any instability or noise may generally result in delays.

  2. Double check the default firmware settings. Depending on the sensor that you are using, there may be a default FW window that is set to 200ms which may explain this delay. Since you are unable to change the FW window to 0, ensure you are writing to the correct register to change the FW window.

  3. It would be best to verify the SPI Timing Data. With a 16Mpbs data rate, every single byte transfer takes (1/16Mpbs x 8bits) = 62.5ns. Ensure that your SPI communications meet the timing constraints of the sensor.

Again, once the specific sensor is provided, we may debug deeper into this issue.

Best,
Krishan