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TPS99000-Q1: Host I2C (PROJ_ON)

Sundar Vinayagam
Intellectual 455 points
Part Number: TPS99000-Q1

Hello TI

We are using DLP5530 Evaluation Kit.

By seeing the schematics of the EVM kit Host SPI doesn't have Proj_ON line but in HOST I2c dedicated Proj_ON line given. 

My question is

Is that dedicated Proj_ON signal line is mandatory, if we select I2C is our communication protocol?  Else we can send command through I2C protocol itself  to turn ON or turn OFF the circuit.

Regards

Saravanakumar

  • +1
    TI__Expert 3005 points

    Hi Saravanakumar - 

    The PROJ_ON signal line is not mandatory if using I2C connector. You can simply leave that wire disconnected for the J1 connector cable.

    Regarding commands to turn off the signal, we would recommend changing the Operating Mode (command 03h) from Display to Standby.

    Alternatively, you could set the Dimming Level (command 50h) to a value of 0, which will ensure no current is flowing through the LED driver circuit.

    Regards,

    Ross

  • 0 in reply to Ross Schneider
    Intellectual 455 points

    Thanks ross

    1. We did changing the operating mode, it works. Thanks for your valid input it help us!!!

    2. Kindly help me to know why the PROJ_ON line is given in DLP5530 EVM kit. I want to know for any other application it requires PROJ_ON and HOST_IRQ.

    3. During testing of DLP5530 EVM kit - observed screen flickering,  at that time current was reducing from 1.47 to 1.12A @ 12V

            Note  : After removing the photo diode connection, no flickering found and the screen turned to pure white current drawn is around  0.9A @12V approx. Help me to find out why its happening.

    Regards

    Saravanakumar D

  • +1 in reply to Sundar Vinayagam
    TI__Expert 3005 points

    Hi Saravanakumar D - 

    For #2 - PROJ_ON is included in the kit in case customers want to use a digital enable / toggle signal to turn off the projector, rather than a communication command.  HOST_IRQ is an output from the DLP chipset that is meant to alert the Host MCU that an error has occurred and the Host should consider taking an action. Details for each of these signals are discussed in the DLPC230 Programmer's Guide.

    For #3 - Can you share the Dimming parameters (including Dimming Level, DAC Levels, Gain, Illumination Bin) where you notice flickering? Perhaps there is an issue with the calibrated settings.

    Regards,

    Ross

  • 0 in reply to Ross Schneider
    TI__Expert 3005 points

    Hi Saravanakumar - 

    I'd like to provide some additional information for #2. For demos and prototypes which use this EVM, it's probably not necessary to connect to the PROJ_ON and HOST_IRQ signals. However, for production designs, TI recommends that customers connect each of these signals to a host MCU. One particular use-case to consider: when a system error has occurred, the HOST_IRQ signal will be asserted high, and the proper way to recover and perform a system reset is to cycle the PROJ_ON signal (and take some action related to the cause of the error).

    Regards,

    Ross 

  • 0 in reply to Ross Schneider
    Intellectual 455 points

    Thanks Ross

    A. regarding Point #2 - We will provide those signal lines for production designs as per TI recommendation.

    B. Regarding Point#3 - Attaching the screenshot of the DLPC230 control GUI

    Regards

    Saravanakumar D

  • 0 in reply to Sundar Vinayagam
    TI__Expert 3005 points

    Hello Saravanakumar - 

    The image resolution was too small so I was unable to see it. Feel free to email the image to me directly - you should have my email address already.

    Regards,

    Ross

  • 0 in reply to Ross Schneider
    Intellectual 455 points

    Hello Ross

    sorry for that......i will email the same

    Regards

    Saravanakumar D