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DLP9500: What is the difference between pattern rate and DMD frames per second on the spec sheet?

Jinsu Choi
Prodigy 20 points
Part Number: DLP9500
Other Parts Discussed in Thread: DLPC410, DLP7000

In the description of the spec sheet of dlp9500, the "pattern rates (1-bit binary) was described as 23,148 Hz and "GLOBAL RESET MODE (Patterns/s)" was 17857.

The description of DLP Discovery 4100 also contained the following sentence: "The DLP Discovery 4100 Development Platform is capable of operating at about 7-10 DMD frames per second (DMD dependent) when connected to a host system's USB 2.0 port."

My questions are below.

1) What is the difference between "23,148", "17857", and "7-10"?

2) When I try to use a PC connected with the controller by USB 2.0 port, it's only 7-10 frames per second due to the speed limit of USB 2.0. Am I right? Then, how do I achieve higher frames per second? (When I use a PC.)

3) When using the DLP9500 in real situations, what should I do to achieve 17857 patterns/s (or near that)? Which things are needed? How do I configure the system? Is it possible?

(I just need the binary pattern rates. NOT color pattern or grayscale.)

  • 0
    TI__Mastermind 46600 points

    Hello Jinsu,

    First, welcome to the DLP section of the TI-E2E forums.

    Here are your questions:

    1. What is the difference between "23,148", "17857", and "7-10"?
      • These are all referring to binary patterns.  The first two are speeds the DMD with the DLPC410 controller is capable of provided you can feed the controller at that speed and in the correct mode.
        • The 23,148 represents "phased" operation, which is analogous to the scrolling shutter on most cell phone cameras.  This allows you to display some blocks while loading and resetting other blocks, effectively "hiding" the DMD reset time.
        • The 17,857 is operating in "global" mode, which means you load the entire array and switch all the micromirrors at the same time.  The consequence is that you cannot re-address the array until the micromirrors have finished mechanically settling.  This is why the rate is lower.
      • The last rate is also binary patterns (frames is a hold-over) but is limited by the USB throughput speed and the memory area in the APPS_FPGA.  There is not enough internal memory to store an entire image (about 1/2 of an XGA image - DLP7000 and about 1/3 of a 1080p image - DLP9500).  
    2. When I try to use a PC connected with the controller by USB 2.0 port, it's only 7-10 frames per second due to the speed limit of USB 2.0. Am I right? Then, how do I achieve higher frames per second? (When I use a PC.)  You are correct. 
      • To achieve this speed you must write your own APPS_FPGA code that pro grammatically generates full image data at the required speed, or you must instantiate a Memory Controller in the APPS_FPGA (Xilinx MIG (Memory Interface Generator) and populate the memory slot.
      • Or you can write APPS_FPGA code to accept input data from the two EXP connectors that you route through to the DLPC410 controller.
    3. When using the DLP9500 in real situations, what should I do to achieve 17857 patterns/s (or near that)? Which things are needed? How do I configure the system? Is it possible?
      • Please see my answer to #2.  Be aware that the EVM is not intended as an end product, but as a sandbox to try things out with the controller.  In the end you will need to design and build your own board.

    Fizix