OPT3101: Calibration

Pritesh Patel

Part Number: OPT3101

I performed perDesignCalibrationCrosstalk and perDesignCalibrationPhaseTemp calibration and I want to make sure results are within acceptable range. There are couple of odd things I found that in the test results that I have questions for.

Question 1: The default distance in SDK is et to 10mm and 20mm. I am not able to read any closer than 350 mm. Can you suggest a solution?

Question 2: In perDesignCalibrationCrosstalk HDR = 1 test results, I see I and Q value suddenly jump at 60C and then continue as temperature increases (image below). Is this normal?

Question 3: In perDesignCalibrationPhaseTemp test for HDR = 0 I am getting slope of 43.7 where as in the demo SDK code and Latte code for OPT3101, coefficients are in single digits between 3 and 5. Is coefficients same as slope of there is additional conversion from slope to coeffieients?

Question 4: In perDesignCalibrationPhaseTemp test for HDR = 1 did not produce any data, phase was always 0 and amplitude was 65535. My test device was set at 500mm from target in a temperature chamber. what could be an issue. I have attached test result excel file.

Test Results:

Internal and Illum crosstalk correction:

[Cortex_M3_0] INFO::Resetting Host
INFO::Writing Initialization sequence I2C registers
INFO::Performing Internal Cross talk Measurement...
INFO::Internal Cross talk Measurement Completed
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
-007750,+004955,0,-0007750,+0004955, 8192, 41543,     +00, -1627.5625, 30.2

INFO::Cover Photodiode with optical shied for illumination Cross talk measurement
Press any Key to continue:

INFO:Performing Illum Crosstalk for TX0 HDR 0
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+007940,+001389,0,+0007940,+0001389, 2296, 0000,     +31, -128.0000, 24.9

INFO:Performing Illum Crosstalk for TX0 HDR 1
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+021962,+012444,0,+0021962,+0012444, 2304, 0000,     +32, -128.0000, 79.6

INFO:Performing Illum Crosstalk for TX1 HDR 0
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+001217,+000238,0,+0001217,+0000238, 2288, 0000,     +30, -128.0000, 3.3

INFO:Performing Illum Crosstalk for TX1 HDR 1
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+000423,-000264,0,+0000423,-0000264, 2288, 0000,     +30, -128.0000, 1.6

INFO:Performing Illum Crosstalk for TX2 HDR 0
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+001351,-000336,0,+0001351,-0000336, 2288, 0000,     +30, -128.0000, 3.7

INFO:Performing Illum Crosstalk for TX2 HDR 1
      I,      Q,S, ScaledI, ScaledQ,tMain,tIlum,tMain(C), tIlum(C),Magnitude
+001023,-000981,0,+0001023,-0000981, 2288, 0000,     +30, -128.0000, 3.7

INFO:Completed Illumination cross talk measurement for all channels
INFO::Loading Illumination cross talk Set
INFO::Set target at a reference distance
Press any Key to continue:

perDesignCalibrationCrosstalk

perDesignCalibrationPhaseTemp

cs600_Calibration 20200725.xlsx

over 5 years ago

0 Alex Bhandari-Young over 5 years ago

TI__Mastermind 25905 points

Hi Pritesh,

1) default distance in SDK is just what we happened to use in the board we used to develop the SDK. You will need to refer to the calibration guides online and set values for your board

2) no this does not look normal. Please confirm auto hdr mode is not active during the test

3) Check the units for this. the coefficient can either be expressed in phase_codes/temp_degrees or phase_codes/temp_codes for which there is a difference by a factor of 8 for the internal temp sensor (you can check the conversion for converting temp codes read from the device to degrees in the temp sensor section of datasheet). The value written to calibration register should be phase_codes/temp_codes and not degrees

4) check if you are saturating the device (amplitude too high). You would see the amplitude overflow flag from the device

Make sure you are following the calibration doc as well https://www.ti.com/lit/ug/slau791/slau791.pdf?ts=1595968083369

And overview of all collateral is here https://e2e.ti.com/support/sensors/f/1023/t/815766

Best,

Alex

0 Pritesh Patel over 5 years ago in reply to Alex Bhandari-Young

Intellectual 335 points

Alex,

Thanks for detailed clarification. I did some of the test again as per suggestions and I have couple of follow up questions.

2) Function perDesignCalibrationCrosstalkTemp calls device::initialize function that initialize device registers. I was expecting SDK to set HDR mode to 0 when running calibration routines as it is setting other device registers required for calibration. But I guess that is missing in SDK. I manually set HDR to 0 while SDK is calling calibration routines and re-perform perDesignCalibrationCrosstalkTemp test. My results with HDR set to 1 still has a I and Q jump at 60C.

3 & 4) I re-performed perDesignCalibrationPhaseTemp test for HDR 0 and HDR 1 with less reflective target at 500mm distance and I received good test results. The phase temp coefficient using phase_codes/temp_codes I am getting 8.08516 for HDR 0 and 4.17045 for HDR 1. Let me know if these results are with acceptable range.

0 Alex Bhandari-Young over 5 years ago in reply to Pritesh Patel

TI__Mastermind 25905 points

Hi Pritesh,

The SDK does take care of the hdr mode automatically while running the calibration functions. The single jump we see in the Q on second graph seems to be the remaining issue and is not expected. Can you share the raw data for these plots outputted by the SDK and we can try to debug further.

Best,

Alex