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DLPLCR70EVM: Maximum 1-bit pattern rate is 32,225 Hz but is it possible to leave the majority of the pattern the same and flip single pixels at a higher rate

James Meech
Prodigy 40 points
Part Number: DLPLCR70EVM

Hello

I am interested in using the DLPLCR70EVM DLP board and the DLPLCRC410 Evaluation Module in a project. 

I need to be able to flip individual pixels at a rate higher than 32,225 Hz.

I understand the the maximum frequency at which we can re-write every pixel in the array is 32,225 Hz but is it possible to flip single pixels leaving the bulk of the pattern the same faster than this? 

Best regards,

James 

  • 0
    TI__Mastermind 48170 points

    Hello James,

    This is a great question.  For this DMD an entire row must be loaded.  Therefore if you have an image that you want to change single pixels, you will have to load all the pixels in each row that has a change.  

    Next there are "mirror clocking pulses" (MCPs).  This causes the micromirrors to change to the new state loaded into the CMOS array.  This is done in blocks.  For this device there are 16 blocks of 48 rows.  This MCP must be followed by a "Settling time" before addressing the pixels again.  The total MCP + settling time is about13 us.

    The 32,225 patterns per second are achieved by using a phased (scrolling) display, much like a scrolling shutter on most cell phone cameras.  One, two, or four blocks of data are loaded and issued an MCP.  While that block is settling the next set of rows is loaded and issued an MCP.  This is repeated until the entire device has been loaded and displayed, and then it starts over at the top.  This allows MCP/settling time to be "hidden" during the loads of other blocks.

    The consequence is that the image is not displayed simultaneously as they are if you use a global MCP.  

    The loading time will improve if you address only rows with changes.  But is still dominated by the MCP time.  

    Fizix

  • 0 in reply to Fizix
    Prodigy 40 points

    Hello 

    Thanks for the fast and detailed reply! 

    What speeds can I expect if I only want to flip pixels in a single row and keep only that row loaded at all times? 

  • 0 in reply to James Meech
    TI__Mastermind 48170 points

    Hello again James,

    Rather than recreate the answers in this thread, please look at the following thread:

    https://e2e.ti.com/support/dlp/f/94/p/935255/3472192?tisearch=e2e-sitesearch&keymatch=DLPA200#3472192

    This should answer the questions you have.

    Fizix