I'm developing a Water Turbidity Sensor based on CN0409.
After got grateful help from @Yoleri Yigit I solved some of issues with ADPD1080 driver.
But, the return signal of photodiodes still too noises, details of issues I have been declare here:
I also have some other questions, please make me clearly understand it !
Thanks all !
I have checked the document that you linked. I think this is a problem with TIA saturation. I see that you have followed the TIA ADC mode section. Did you sweep the values for the AFE offset an…
1. The above formulas are for non-ratio and ratio measurements, respectively. You are correct that the values in D2 and D4 can be directly obtained from registers 0x64 to 0x6B if the detectors are not saturated. For x and y, these are ratios of D2/D4 for the timeslot using LED1 or D4/D2 for the timeslot using LED2.
2. The LED pulse and period affects the active time, average current. You can also decrease the current to the LEDs using the LED Control Registers for the LEDX_peak. However, increasing the LED current using the same methods increases the SNR of the measurement. Just be sure to operate below saturation. You can read more on this in the Optimizing SNR section in the ADPD1080 datasheet.
I have checked the document in the link you sent and I have a couple of questions:
Thank so much for your information !
Yes, I have been disable sample updates when reading the data in non-interrupt mode.
I also configure the ADPD1080 to working in TIA ADC MODE by following page 43 on the datasheet.
But the return value is not like as describe on datasheet, please refer below document for more information about my inssues:
I have checked the document that you linked. I think this is a problem with TIA saturation. I see that you have followed the TIA ADC mode section. Did you sweep the values for the AFE offset and to come up with the 22us value that you used?
The saturation problem is a common issue when using large photodiodes such as the OPF430. What happens with the TIA in these situations is also described in page 43. Additionally, you should also set bit 7 of register 0x58 to enable the configuration of the integrator as a buffer in TIA ADC mode.