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What is the LED_CONTROL register?

James Strother1
Prodigy 20 points
Other Parts Discussed in Thread: DLPC300

Hello,

I've been thinking of using the LightCrafter for a recent project, and I've been going through the available documentation. I had a couple of questions that I hoped someone could answer

1. The source code for the MSP430 frequently modifies an "LED_CONTROL" register on the DLPC300 (0x8C).  But this register appears to be undocumented in the DLPC300 programmer's guide. Any idea where I could get more info on this? 

2. Related to the first question, if LED_CONTROL is disabled (whatever that does) will the DLPC300 perform all of its other functions normally?  Specifically, will it happily drive the DMD sequences if the LEDs are off?

Thanks!

  • 0
    TI__Expert 4500 points

    Hello James,

    Welcome to TI DLP E2E Community!

    1. The 0x8C register is used to enable (0xD) and disable (0x0) the LED Strobe signals( LED_BLU_EN, LED_GRN_EN and LED_RED_EN signals on LED driver interface circuit). Thanks for pointing this out, we will document in next revision of the DLPC300 Programmer's guide.

    2. The LED Strobe signals are enabled by the FPGA and the disabling these signals would power off the LEDs and in turn the feedback circuit will cause the LED_ENABLE to go low. The DLPC300 operates normally except it disables the LED_PWM signals.

    Can you please share more details about your application so we can help you better.

    Regards,

    Divya

  • 0 in reply to Divya Reddy
    Prodigy 20 points

    Hi Divya,

    Thanks for getting back to me.  Our application requires replacing the LEDs with an alternative light source.  We recognize that this will interfere with the temporal dithering used for grayscale, and so it would only be used for 1-bit images.  Our plan was to reprogram the MSP430 to disable the LED control in the DLPC300 and then remove the various safety checks associated with the LEDs (thermistors, overvoltage, etc).

    Do you foresee any problems with this approach?

    Thanks,

      James

  • 0 in reply to James Strother1
    TI__Expert 4500 points

    Hi James,

    Sorry for delay in my response. Please make sure you are operating within specified temperature limits and also note that the warranty on LightCrafter will be no longer valid after these modifications.

    Regards,

    Divya