AFE4405EVM: auto calibration

Hi Amy,

Thanks for your reply. In the meantime, I've prepared the environment to modify the firmware of the EVM board by using CCS. Furthermore, I've found that the current GUI supports "calibration enable" under the ADC capture & analysis tab.

The problem is that even though I run the calibration according to the guide which pops up when the "enable calibration" is checked, the result is a failure.

Here are the steps.

1. After the "enable calibration" is set, the capture started. The screen shows LED1 is fixed at 0.3V (all the time) and other LEDs show noisy signals. (The 1st picture) From the firmware, I can see that LED1 is default target for calibration.

2. After the step, read all the registers into the GUI. And then unchecking the "enable calibration", capture started. The result is that LED1 showed a saturation or very noisy signal which are near 1.0V even though the calibration is done. My expectation is that the DC values of the resultant LED1 signal is around 0.4 ~ 0.6 volt or simply 0.5 volt.

3. The following pictures show that the parameters after the calibration. The problem is that the current value of LED1 is too small(0.782mA) and the gain is large which will make noisy signals. This results was measured on wrist. Tried many times but the results were the same. Even tried at fingers, the results were the same.  To overcome this, if some initial values need to be modified in the firmware, please let me know. I can modify and rebuild the firmware now.

4. The sampling freq and duty cycles were 100Hz  and 3% respectively.

Regards,

Konan