DLPLCRC410EVM: Unexpected Second Reset Pulse on Global Reset with D4100Explorer

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Replies: 6

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Part Number: DLPLCRC410EVM

Hello,

I have noticed a behavior I can't find documentation for using the D4100 Explorer GUI for controlling a DLP7000 (0.7 XGA 2xLVDS Type-A DMD: 1024x768 resolution) part via a DLPLCRC410EVM board.

I am probing test point 28 (an MBRST line) and have observed what appears to be a second mirror clocking pulse after the initial (expected) pulse. This pulse occurs approximately 7ms after the initial pulse and seems to have some variability on the exact time delay between pulses. I should also note that it seems to not always appear on every frame load. 

See below for scope traces of the behavior in question. 

What is this? Is this documented somewhere and I cannot find it?

This is the information form the about page of the D4100 GUI:

This is the GUI script I have been using for toggling at a 50/50 duty cycle of all on, all off, with a second between frames. 

Discovery 4100 Explorer Script, SW Version 2.1.0, 10/2/2019

1 Loop  1
2 Until Break
1 Image
2 C:\Users\install\Documents\images\all_on.bmp
1 Load
2 Global
1 Reset
2 Global
1 Delay
2 Msec 1000
1 Image
2 C:\Users\install\Documents\images\parallel.bmp
1 Load
2 Global
1 Reset
2 Global
1 Delay
2 Msec 1000
1 Loop  1
2 End 

The images used are simply either all white (all_on) or all black (parallel) 1024x768 bitmaps. 

Any insight on this matter would be appreciated.

Thanks for you help, 

-Danyal

6 Replies

  • Hello Danyal,

    Good to hear from you again.

    Could you try creating a script that simply loads an image and resets it.  No loops, and one delay. 

    Then first try "Run Once".  Check to see if this is occurring every time you click run once.

    Next try just "Run", which should run the script repeatedly until you hit stop.

    Try both separate load and a separate reset (as in your snippet in your post) and try the "Load and Reset - Global" command.

    Please let me know the results.

    Fizix

  • In reply to Fizix:

    Hi Fizix, 

    Apologies on the delay, I was not in the lab on friday and wasn't able to check your suggestions. It seems though, that this second pulse can appear in all modes you suggested. 

    I had tried running my original code with the "Load and Reset - Global" command instead of doing it separately as I showed in my original post, and had the same results. 

    Here are the traces for only loading an all on image, separate load and reset, and delay of 1ms afterwards. This was done over ~ 15-20 "Run Once" sequences. 

    Here are the traces for only loading an all on image, separate load and reset, and delay of 1ms afterwards. This was done over ~ 15-20 cycles of the "Run" command.

      

    Here are the traces for only loading an all on image, combined load and reset, and delay of 1ms afterwards. This was done over ~ 15-20 "Run Once" sequences. 

    Here are the traces for only loading an all on image, combined load and reset, and delay of 1ms afterwards. This was done over ~ 15-20 "Run" cycles. 

    The story is the same for loading Off images as well. 

    Regards,

    -Danyal

  • In reply to Danyal Ahsanullah:

    Hello Danyal,

    Now it my turn to say, "sorry for the delay".

    I am a bit baffled by this behavior.  It is definitely not expected behavior, since you are doing a global reset, there should only be one pulse.

    One last simple test, instead of a loop can you open the file with something like notepad and save it to another name and then delete lines 3 & 4 and lines 21 & 22.  Then copy everything except the first two lines (the are the file header) and paste in a bunch of times.  Say 20 or 30.

    I am attempting to determine if this a a loop thing (either from the loop command or the run continuous loopback).

    Fizix

  • In reply to Fizix:

    Hey Fizix, 

    I am afraid the unrolled loop still gives the same result as the old one. I have tried running it, running it once, and stepping through it and was still able to see the second pulse.

    If you want the trace I can upload it, but It's just more of the same. 

    As an additional bit of information, I tried illuminating the center of the DMD with a 532 nm green laser, and used an APD to measure the temporal response of the mirrors. While it confirms the second pulse is not some odd artifact of probing (although I fail to see how using a 1GHz rated x10 scope probe would produce any issues here), it also seems to suggest some odd intermediate action happening with the mirrors around halfway between the two pulses.Since there is a 1 second delay immediately after each reset call, I can't imagine this is some sort of movement caused by the SRAM. See the below plots. 

    Zoomed in regions of interest: 

    initial reset:

    Second reset:

    Intermediate "ring":

    I am not sure what to make of this. Any ideas? If we need to start trying to monitor bus traffic or the possibility of interfacing something via JTAG I will need to see about getting the hardware and software tools for such a setup.

    Regards,

    -Danyal Ahsanullah

  • In reply to Danyal Ahsanullah:

    Danyal,

    I am studying this, but do not have an answer at the moment.

    I will see if I can duplicate this on one of our platforms.

    Fizix

  • In reply to Fizix:

    Hi Fizix, 

    Thanks for looking into this, If you need any specifics feel free to let me know. 

    Regards,
    -Danyal