• State Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 1 answer
  • Subscribers 32 subscribers
  • Views 965 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

OPT4048DTSEVM: OPT4048

christian scherabon
Prodigy 30 points

Part Number: OPT4048DTSEVM
Other Parts Discussed in Thread: OPT4048

I do have some troubles with the GUI of the Eval Kit:

Channel Live Window (see Fig. 3-15 user guide): The colour coding of the ADC codes seems not to fit the Z and W values. Is channel 2 now blue or black of the ADC register codes?

How can it be that if the ADC codes for channel 2 (wheter it is blue or black) is at maximum with varying light and Z value is still rising? I do understand that channel 2 equals Z.

How is it possible that you can select a Gain of 7 or 8 in the GUI wheras the device only supports 6 levels. More interestingly: IT WORKS!! A miracle!

  • 0
    TI__Genius 9675 points

    Hi Christian,

    Can you share screen captures of your GUI to show exactly the problem you are seeing?

    I have an EVM as well to see if I notice the same issue.

    Thanks,

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 30 points

    I have a blue 470nm LED.

    Issue 1:

    You see the codes value of 0x2708000 (equals 40927232 dec) on top in blue color. Because this is the highest value this should be the blue channel which is 2 (=Z) according to the data sheeet. But in the graph the blue coded y axes is denoted as channel 3, but it should be channel 2! It seems that in the graph channel 2 and 3 are mixed up. They have the right values but the wrong labeling channel wise.

    Issue 3:

    Above I have selected "Mode Select" Range 8. The data sheet specifies a gain range of 0 to 6. The GUI allows 0 to 8! And it works!

    Issue 2:

    Blue channel is 0x3ffffc0 which is maximum. Z value is around 11622.

    Now  I habe increased the LED intensity:

    Below the Blue channel codes is still at maximum (0x3ffffc0), but Z value is now around 28212 (more than double). How is that possible if channel 2 (the blue one) is equal to Z according to the data sheet.

  • 0 in reply to christian scherabon
    TI__Genius 9675 points

    Christian,

    it seems that channel 2 and 3 are correct on values (right side) however it is flipped in position on the codes (left side). Please interpret the black line as channel 3 and the blue line as channel 2 on the codes side (right side). We will fix this in the GUI.

    Regarding the mode select, the maximum gain range should in fact be 6 per datasheet spec. The range values of 7 and 8 are not interpreted as valid, but most likely have the gain set to 6 in the software program. We will fix this in the GUI as well.

    Thanks for bringing to our attention.

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 30 points

    Dear Jalen,

    Regarding mode select: 
    The ranges 7 and 8 are working, therfore the gain is NOT set to 6 by the GUI. I have found out in the register view that the IC supports even 9 settings!

    On the bottom of page 17 of the data sheet this is indirectly confirmed: "With maximum value for register EXPONENT_CHx being 8 ADC_CODES is effectively a 28 bit number".

    You did not respond to issue 2 where it seems that channel 2 does not equal to Z.

    Kr

    Christian

  • 0 in reply to christian scherabon
    TI__Genius 9675 points

    I will have to check with another team member on the range settings for you.

    In regards to issue 2. As you mentioned channel 2 and channel 3 are in fact mixed up.

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 30 points

    Dear Jalen,

    sorry, concerning issue 2 I believe I have not expressed myself correctly. What I meant is that the blue channel (which is in fact channel 2 of the IC) seems not to equal Z of the CIE colour space, as the datasheet suggests. It looks like that the GUI combines several channels for calculating Z of the colour space. This is independent from the mixed up channels 2 and 3 in the GUI.

    kr,

    Christian

  • 0 in reply to christian scherabon
    TI__Genius 9675 points

    Christian,

    The GUI performs the same light and color measurements as described in section 8.3.4.5 of the Datasheet.

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 30 points

    Well that means that channel 2 does not equate Z of CIE as the datasheet might suggest.

    Does the GUI use the conversion matrix of equation 16 of chapter 9.2.4 or a different one?

    Thanks a lot,

    Christian

  • 0 in reply to christian scherabon
    TI__Genius 9675 points

    Christian,

    Yes, the conversion matrix of equation 16 is being used in the GUI.

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 30 points

    Dear Jalen,

    where you able to find out how many range settings are available?

    kr,

    Christian

  • +1 in reply to christian scherabon
    TI__Genius 9675 points

    Hi Christian,

    Sorry for the delay here, but I will have to refer back to the datasheet on the 6 ranges for how the OPT4048 is intended for use. We are working to remove ranges 7 and 8 from the GUI and publishing soon.

    Please use up to range 6 for proper operation of the OPT4048 device.

    Thank you,

    Jalen