AFE4400 - CALIBRATION

Nazrul Khan

Other Parts Discussed in Thread: AFE4400

Hello,

I am using AFE4400. To set the DC target threshold value to the suggested level, I am trying to calibrate LED current and TIA Gain. For that I have started the system with the default register settings and then calculating the DC value from the samples received. Based on the value, I try to rewrite new values to the concerned registers(tweaking the concerned register). But, I am not getting the desired results, I am expecting. My question is, once the system starts working, can I rewrite the control registers? My intention is to create an auto calibration routine. Is it possible? Is there any code example for that. Regards.

Nazrul

over 8 years ago

0 Praveen Aroul over 8 years ago

TI__Mastermind 49906 points

Hello Nazrul,

Yes you can reconfigure the timing and control registers any time.

You will need to ensure the SPI_READ bit (register address 0, bit 0) is set to 0 before writing to a register.

Additionally if there is any change to the signal characteristics like changing the LED current, TIA gain etc, you will need to wait for each of the four switched RC filters to fully settle to the new settings.

We do not have calibration code example for AFE4400 but I have attached the gain and current controlled calibration routine flowchart that you could probably use to implement the auto calibration.

/cfs-file/__key/communityserver-discussions-components-files/73/2783.AFE4400_5F00_Gain_5F00_Calibration_5F00_Flowchart.pdf

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AFE4400 - CALIBRATION