DLP3010EVM-LC: I2C communication error when getting system temperature

Hi user,

Welcome to the TI E2E forums and thanks for showing interest in the DLP technology.

I would recommend you to use DLPDLC-GUI (https://www.ti.com/tool/DLPDLC-GUI) to check the system temperature first.

If the readback temperature looks correct in GUI, then you can compare the different with API.

If the readback temperature looks wrong in GUI, can you check the thermistor used with the system and its integration to the design. 

Thanks,

Lori 

I have already checked the system temperature by using DLPDLC-GUI.

Then, the temperature value was 0 (i.e. wrong value) and communication error was displayed.

 On the other hand when I connected a DLP3010EVM (not my system) to my PC, the temperature value is correct in the DLPDLC-GUI.

The thermistor in my system is the same as one in the DLP3010EVM.

Now I am checking the integration of my system again (I have already checked many times), but please let me know if the operation has been confirmed that the temperature sensor value can be obtained correctly with the firmware.

Hi user,

Yes, the system temperature command should be obtained correctly with the firmware if the integration is correct.

Regards,

Lori 

Thank you so much.

I will check if the integration of my system is correct.

I checked the integration design drawings of my system, but I couldn't find the part that seems to be incorrect.

Instead, I found two phenomena seemed to be caused by incorrect behavior of DLPC3478 firmware.

    (1) I found that there was no reference input voltage (ACMPR_REF) to the AFE comparator of DLPA3000 from host (i.e. DLPC3478) when I request system temperature by using DLPDLC-GUI.  This voltage should be supplied from GPIO_10 (RC_CHARGE) of DLPC3478.  The AFE comparator is written at "Figure 24. Measurement System" in the datasheet of DLPA3000.

    (2) Also, I found that there was no input voltage to the thermistor voltage divider circuit from host (i.e. DLPC3478). This voltage should be supplied from GPIO_11(THERM_PWR).

If the firmware of DLPC3478 is normal, at least some voltage will be supplied on these GPIOs, but the voltage of these pins were not changed from 0V. I wonder if these pins are being correctly manipulated by firmware for DLPC3478.

Similar issue was reported in following page:

    https://e2e.ti.com/support/dlp-products-group/dlp/f/dlp-products-forum/987397/dlpc3435-temperature-read-and-rc_charge-not-working?tisearch=e2e-sitesearch&keymatch=RC_CHARGE#

Please let me know what should I do to solve this problem.

Hello,

Thankyou for the detailed information. The team is looking into this request and will get back to you in a couple of days.

Regards,

Mayank

Thank you for the reply.

I will wait for the result.

Hi,

Thank you! We will keep you updated.

Regards,

Lori

Hi,

If you are comfortable sharing the schematic, I've sent you a friend request on E2E. Please send me a private message once you have accepted it.

Thanks,

Lori

Thank you for the suggestion.  I have accepted it and sent you a private message.