Question about working AFE4400 PPG Module

Hello Inho,

The control and timing registers of the AFE4400 have to be configured using the SPI to turn on the LED on the PPG sensor.

Hi Praveen,

Thank you for your reply.

And, Is it needed only SPI port for working AFE4400? or  is it needed PD_ALM, LED_ALM, DIAG_END, ADC_RDY, /RST, /AFE_PDN, also?

I'd like to designed minimum pins.   

Please, inform me working AFE4400 using minimum pins, ASAP.

Best Regards,

Inho Jeon 

Inho,

PD_ALM, LED_ALM, DIAG_END, and ADC_RDY are all output signals from the AFE and are not absolutely necessary, but can be very helpful if you ever wanted to debug.

RST and AFE_PDN are both active low inputs to the AFE, we do not recommend leaving these pins floating. They should be driven by a GPIO or pulled externally to a logic level in case you do not want this feature.

Hello Amy,

i'd like to not controlled  AFE_PDN and RST. 

I checked AFE_PDN level is not by Vcc. So, AFE_PDN is pulled up Vcc.

But I checked RST level changed is by Vcc level with oscilloscope.
So RST pin is floated.

Is that some problem working AFE4400?

Best Regards,

Inho Jeon

Hi, Amy

Thank you for your repliment.
And, RESET delay time is more than 100ms on AFE4400 DataSheet : Is that mandatory? or recommend?

Best regards,
Inho Jeon

It is required. Please implement in your design.