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DLP6500FYE: Output Trigger Confusion

Tristan Carlson
Prodigy 110 points
Part Number: DLP6500FYE
Other Parts Discussed in Thread: DLPC900

Hello, 

I am trying to measure the output triggers for my DLP6500 DMD, indicated as J24 pins 1 and 2 in the TI User Guide. From what I understand, J24 pin 1 should be high when the mask is on (for the exposure time duration) and low when the mask is off (for the dark time duration and if the dark time is 0us, then this output will remain high). J24 pin 2 should have a 20us pulse at the beginning of a new mask (indicating the transition from the previous mask to the new mask). I see that you can also invert these signals and set a time delay for the rising and falling edges. 

I am using an Arduino for input triggering and to measure the trigger outputs from the DMD. I have the J24 pin 2 connected to the Arduino analog voltage input A3 (as seen in the photos) so I would expect to see a 20us pulse for every mask change (if the Arduino time resolution is good enough) but instead when the dark time is set to 0us I see a constant high voltage and when there is a non-zero dark time I see a high voltage corresponding to the exposure time and low voltage corresponding to the dark time. This is what I would expect to see from J24 pin 1, is there any way the user manual pins are swapped? I am currently unable to read the J24 pin 1 voltage. 

Initially, I thought J24 pin 1 and 2 could be connected through excess solder, but from visual inspection and an electrical test, it does not seem that they are connected.

  • 0
    Prodigy 110 points

    Because I cannot attach Arduino files, I have included a Word doc with the code. Most of it can be ignored as it is for input triggering.

    TriggerRead_TriggerGen.docx

  • 0 in reply to Tristan Carlson
    TI__Expert 3040 points

    Hi Tristan,

    As a first step, i would recommend to capture Trigger out signals on the Digital Oscilloscope and confirm waveform is displayed as expected.
    For doing this test, you can simply use pattern on the fly mode without trigger input enabled.

    As explained in the DLP LightCrafter Single DLPC900 EVM User guide, Section 1.5.2

    The trigger outputs on J24 are outputs to control external devices. While trigger output 1 frames the exposure time of the pattern, trigger output 2 pulses to mark the beginning of each pattern


    Make sure the Jumper connection on Trigger out voltage sectors J25, J22 are across pins 1 to 2 for 3.3 V output.
    Refer to Table 1-1

    As per the Output Trigger Connectors description in Table 4-2,
    Trigger out 1 signal should be tapped at Pin 2
    Trigger out 2 signal should be tapped at Pin 5

    Please verify and update the result.

  • 0 in reply to SHIVAKUMAR R
    TI__Guru 54480 points

    Hello Tristan,

    I wanted to add to what Shiva put in his answer.

    The User Guide he referenced can be found at this link ti.com/lit/ug/dlpu101/dlpu101.pdf.

    Please refer to section 1.5.2 on page 14.  This page indicates that you must must either select a voltage with the jumper(s) listed or drive the Trigger Supply pin externally.  This section says, ". If no voltage is selected, then the onboard logic is not functional and any outgoing or incoming signals are not available."

    Fizix

  • 0 in reply to Fizix
    Prodigy 110 points

    Hello everyone, 

    I apologize as it seems an earlier message from me didn't go through (I meant to send it shortly after my first series of posts). I found the pin diagram in the user manual and was able to successfully read the DMD trigger outputs.

    Thanks!