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DLPLCR4500EVM: About the external trigger

Kokoro Fujiwara
Prodigy 120 points
Part Number: DLPLCR4500EVM
Other Parts Discussed in Thread: DLPC350, DLP4500

Hello, I have a question about the external trigger mode.

When I want to show three numbers of petternes continuously (Exposure time =pattern sequence =10ms),

what type of signal should be applied to J11 pins?

Could you tell me the 2 input trigger signals about the above case ?

Regards,

Kokoro

  • 0
    TI__Genius 12555 points

    Hello Kokoro,

    Welcome back to the E2E forum.

    The following description of the input triggers is taken from Section 4.1 of the DLP4500EVM User's Guide.

    In pattern sequence mode, the 48 bit-planes can be preloaded from flash memory and then sequenced with a combination of patterns with different bit depths. To synchronize a camera to the displayed patterns, the DLPC350 supports two trigger inputs and two trigger outputs. TRIG_IN_1 pulse indicates to the DLPC350 to advance to the next pattern, while TRIG_IN_2 starts and stops the pattern sequence. TRIG_OUT_1 frames the exposure time of the pattern, while TRIG_OUT_2 indicates the start of the pattern sequence or internal buffer boundary of 24 bit-planes. For example, in Figure 3-10, the VSYNC starts the pattern sequence display. The pattern sequence consists of a series of three consecutive patterns. The first pattern sequence consists of P1, P2, and P3. P3 is an RGB pattern, it is shown with its time-sequential representation of P3.1, P3.2, and P3.3. The second pattern sequence consists of three patterns: P4, P5, and P6. The third sequence consists of P7, P8, and P9. TRIG_OUT_1 frames each pattern exposed, while TRIG_OUT_2 indicates the start of each of the three pattern sequences. In Figure 3-11, a pattern sequence of a group of four patterns are displayed. TRIG_OUT_1 frames each pattern exposed, while TRIG_OUT_2 indicates the start of each four-pattern sequence. TRIG_IN_1 pulses advance the pattern.

    Please let us know if this answers your question or if further clarification is needed.

    Regards,

    Austin

  • 0 in reply to Austin Snyder
    Prodigy 120 points

    Hello Austin,

    Thank you for your reply.

    As mentioned above, if I want to show the continuous pattern, TRIG_IN_2 pulse shoud be just one pulse which indicates start of the pattern sequence.

    For example, when I set the Exposure time =pattern sequence =1ms , TRIG_IN_1 pulses are 1 kHz pulse trains and TRIG_IN_2 is just one pulse.

    Is this correct?

    Regards,

    Kokoro

  • 0 in reply to Kokoro Fujiwara
    TI__Expert 5260 points

    Hello Kokoro,

    We can look into this and clarify. Thank you for your patience.

    Regards,

    John

  • 0 in reply to Austin Snyder
    TI__Expert 7000 points

    Hi Kokoro,

    So please keep in mind there are actually different trigger modes. The above description is for mode 1 so make sure you set that accordingly.

    You can read more about trigger modes from the DLP4500 EVM user guide in section 3.3.1.

     

     

    You can also read more about trigger modes and examples in the DLPC350 datasheet in section 8.4.1.

    https://www.ti.com/lit/gpn/dlpc350

     

     

     

    Please see the examples and how the various trigger signals are used.

    Hope this helps.

    Thanks,

    Alex Chan

  • 0 in reply to Alexander Chan
    Prodigy 120 points

    Hello Alex,

    Thank you for your apply.

    I understand the meaning of each trigger.

    As a confirmation, in the GUI, Trigger mode 1 corresponds to Pattern sequence mode and Trigger mode 2 corresponds to Pattern sequence mode[Variable Exposure]. 

    Is my understanding correct?

    Regards,

    Kokoro

  • 0 in reply to Kokoro Fujiwara
    TI__Genius 12555 points

    Hello Kokoro,

    The GUI does not appear to support Trigger mode 2. The trigger mode that is being used can be seen on the right hand side of the GUI.

    In Pattern Sequence mode trigger modes 0 or 1 are selectable. In Pattern Sequence [Variable Exposure] mode trigger modes 3 or 4 are selectable.

    Regards,

    Austin

  • 0 in reply to Austin Snyder
    Prodigy 120 points

    Hello Austin, 

    Thank you for your reply.

    Could you tell me how does the external trigger work in Pattern Sequence [Variable Exposure] mode (trigger mode 3 or 4)?

    Regards,

    Kokoro

  • 0 in reply to Kokoro Fujiwara
    TI__Expert 7000 points

    Hi Kokoro,

    Please see the following description on the different modes from the DLP4500 EVM User Guide. 

    For more clarification you can only use Vsync trigger mode with Video Port pattern source.

    For pattern source flash you can only use the internal/external trigger mode.

    Both pattern sequence mode or pattern sequence mode (variable exposure) has sequence setting options to support vsync trigger or internal/external trigger.

    Thanks,

    Alex Chan

  • 0 in reply to Alexander Chan
    Prodigy 120 points

    Hello Alex,

    I know the function of Pattern Sequence [Variable Exposure] mode, but how should I set the external trigger?

    I would like to know how does the external trigger work in the Pattern Sequence [Variable Exposure] mode.

    Regards,

    Kokoro

  • 0 in reply to Kokoro Fujiwara
    TI__Expert 7000 points

    Hi Kokoro,

    Please see the following.

    In the GUI you can select External Positive or External Negative edges as the trigger type.

    Also see section 7 of the DLP4500 EVM User Guide that talks about trigger connector information.

    Thanks,

    Alex Chan

  • 0 in reply to Alexander Chan
    Prodigy 120 points

    Hello Alex,

    Sorry, could you tell me the difference of the external trigger between Pattern Sequence mode and Pattern Sequence [Variable Exposure] mode?

    Regards,

    Kokoro

  • 0 in reply to Kokoro Fujiwara
    TI__Genius 12555 points

    Hello Kokoro-san,

    The operation between the two is identical except in regards to the exposure time for each pattern. The following excerpt is taken from Section 3.3.2 of the DLPLCR4500EVM User's Guide:

    When operating in Pattern Sequence [Variable Exposure] mode, use this subtab to set the sequence settings. All of the sections are identical to the Sequence Settings subtab with the exception that the Pattern Exposure time and Pattern Period are now set on a per pattern basis rather than set to the same values for all patterns in the sequence.

    Kind regards,

    Austin