Hi. I am using EVAL-ADPD4100Z-PPG for heart rate monitoring.
Are you able to share an example configuration for heart rate monitoring using ADPD4100 (SPI)?
It would be a great help and really appreciate it.
Hi. I am using EVAL-ADPD4100Z-PPG for heart rate monitoring.
Are you able to share an example configuration for heart rate monitoring using ADPD4100 (SPI)?
It would be a great help and really appreciate it.
Hi. Sorry to disturb you.
I tried to read in FIFO but it gives me 0xFFFF.
I have checked the configurations they are correct.
Time slot A configuration
How do I read the output values?
I appreciate the help.
Thank you.
Hi. I forgot to set 1 to Go Mode. I changed the three green LEDs with each 8.2857mA . Therefore, total of 24.857mA. I changed the Rf to 100K ohms and Rint stay as 400K ohms to reduce the gain. Therefore, gain is 100k/400k = 0.25.
I have checked the mask version which is 1.
I am reading the Timeslot A Signal Lower half Channel 1 register.
The result is as follows:
When the three green LEDs are no covered:
When the three green LEDs are covered:
Is the results correct? I can see that the values stabilizes but I don't understand what the value represent.
Can I ask what does the two bytes represent in the Timeslot A Signal Lower half Channel 1 register?
Is the FIFO Data size = Signal size? cos the FIFO Threshold interrupt is always high after setting the FIFO Threshold to signal size and I have checked that INT_ACLEAR_FIFO is high by default.
Sorry to trouble you. I appreciate you have given me so far.
The result will change based on the photodiode current generated. There is no universal correct result in an optical system. The ADPD4100 measures the current generated on the photodiode and the reflected light could differ from measurement to measurement. Typically, to evaluate the system, a fixed reflector setup with a black cover to eliminate ambient light is used. You fix the board to a certain distance to the white cardboard and measure a fixed reflected signal so that the output just changes by the noise level of AFE. Therefore I unfortunately cannot tell exactly if this correct or not.
The value you are reading is the Timeslot A Signal Lower half Channel 1 register, which is the register for channel 1 of the Timeslot A that stores the lower half of the signal values. So it represents the lower half of the output LSBs.
FIFO data size is chosen by the user. (Refer to page 20 FIFO section)
It's not necessarily equal to signal size, you can allocate FIFO data to various different data (lit,dark,signal). It's up to the user how they manage FIFO, whereas register 30-8F stores them separately in different registers.
After FIFO is read, FIFO threshold interrupt is cleared as INT_ACLEAR_FIFO is enabled. But I guess you overflow the FIFO or do not even read it so it doesn't clear. You should check if you're reading FIFO appropriately. Please read the datasheet pages 20-21 for FIFO section. Reading register 30 is not necessarily equal to reading FIFO.
To check overflow, register 0x0000 bit 13 is the place to check.
I hope this will help. I am not sure if I understand the questions but I tried my best to answer to my understanding.
