AFE4404: AFE4404 configuration and functions

Jonathan Navor

Expert 7845 points

Part Number: AFE4404

Hi Team,

Good day. Could you please help to check our customer's concern below.

I have attached here the inquiry from the customer.

The function and usage method of RESETZ, ADC_RDY and CLK are not well understood yet. How should I configure and use it?
I can use I2C to communicate with AFE4404. I configured it in the order of Table 5 in the data sheet, but the LED cannot be lit.
What is the meaning of the values configured in the LED_STC/LED_ENDC registers?
What is the meaning of the values read from the registers 2A~2F?

The'.c' and'.h' files used have been attached here, please have a look.

AFE4404 configuration and use attachment.zip

Thank you in advance for the support.

Best regards,

Jonathan

over 2 years ago

0 Praveen Aroul over 2 years ago

TI__Mastermind 49176 points

Hello Jonathan,

Please ask customer to refer to the FAQ link for AFE4404 sign of like after power up.

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/369445/afe4400-afe4490-afe4403-afe4404-faqs

The AFE4404 datasheet section 8.3 describes the registers for turn on LEDs, sampling, conversion etc.

0 Jonathan Navor over 2 years ago in reply to Praveen Aroul

TI__Expert 7845 points

Hi Praveen,

Apologies for the late response. Our cusotmer's have raised another questions regarding AFE4404. Could you help to answer.

Here it is:

"I am not sure that the data I read from the register 2A~2F is accurate, and I am not sure whether the LED and the receiving diode are working properly. Now I want to clarify the relationship between the receiving diode and the ADC conversion.
1. How is the receiving diode converted into an ADC, and in what form is the data stored in the register?
2. How does sampling time affect this?
3. What is the impact of sampling times?

Thank you so much.

Best regards,

Jonathan

+1 Praveen Aroul over 2 years ago in reply to Jonathan Navor

TI__Mastermind 49176 points

Hi Jonathan,

1. Refer to Table 2 in the datasheet for an understanding of how the PD currents are converted to TIA output voltage. The ADC converts this voltage to adc codes in twos complement format.

2, 3. Depending on the Rf gain and Cf setting, the sampling time will affect the readings. Refer to section 8.3.1.3 in the datasheet.

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AFE4404: AFE4404 configuration and functions