Hi,
Iam using AFE4490 for computing SpO2 saturation. I'm following the below steps in sequence to configure the AFE4490.
1. Pulling RESET and PWDWN pin HIGH using GPIO of the controller.
2. Configuring the AFE to write mode by writing CONTROL REG with value 0x00000000
3. Configuring the registers with required values to operate at 1kHz. (Produce AFE DATA READY @ 1ms)
4. PWDN REG is written to power up Tx,RX and AFE section of AFE4490 (The LED at the end of the SpO2 cable gets ON )
4. Configuring the AFE to Read mode by writing CONTROL REG with value 0x00000001
5.Offloading the task of reading IR and RED channel value at every 1ms to DMA.
It is observed that after some time the interrupts from AFE4490 stops and the LED at the end of SpO2 Cable is also OFF.It is similar to AFE4490 is brought to RESET.
I can bring up the AF4490 back to action only be re-doing all the steps from 1 to 5. After offloading to DMA I'm just reading two reg values at every 1ms but how does AFE4490 goes into RESET is not understood.
I measured the voltages of PWDWN Pin and RESET Pin when the AFE4490 stop ,they are all pulled HIGH. I suspecting a spurious LOW pulse at RESET or PWDN from GPIO of controller causing this issue, tried connecting the PWDWN and RESET pin directly to 3.3V but the AFE4490 still shows the same behaviour.
It sometimes works for more than 18Hrs and stops , some time just after 2Hrs. Please help me in resolving the Issue. what could be the reason for such behaviour of AFE4490 ?
