Syncing HDMI input with trigger out

Any suggestions? If anyone has ever used HDMI output and the external trigger, please let me know how you set it up.

Hi Jian Tay,

Sorry for the delay in my response. Please see my responses below.

I'm trying to use the LightCrafter in HDMI input mode, with 60 Hz and 1-bit monochrome images selected to get 60 * 24 frames per second. How do I configure the external trigger output to work? Currently, pins 3 and 4 on the trigger connector (furthest away from the side edge of the board) are connected via coaxial BNC cable to a Tektronix oscilloscope. I don't have the scope specs with me, but I am guessing that it has high input impedance.

It sounds like you have your equipment setup correctly, but just for reference here is a link to a thread with a diagram that you can verify your connections with. http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/850/t/185560.aspx

Based on the manual, I expected to see a trigger signal every frame i.e. ~0.7 ms. However, all I'm seeing is an odd spike at 60 Hz. 

I would also expect to see a trigger every 0.7ms. Could you post a screenshot of the GUI so I can see your settings?

I've also tried the work-around suggested here: http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/94/t/249542.aspx to enable the external trigger using the pattern sequence tab. This somehow gives me a 30 Hz trigger, but raises even more questions. For example, what is this signal synced to? Also there seems to be no way in this case to change the trigger frequency.

In HDMI video mode, the output trigger is not configurable. You can only configure the output trigger when in Pattern Sequence mode. The signal is synced to the exposure time. 

Please verify your connections with the diagram from the thread I mentioned and send me a screen shot of your settings from the GUI. Hopefully we can fix your problem quickly!

Best regards,

Blair

Hi Blair,

Thanks for replying. I checked the link you sent regarding the connections and it looks like what we have is correct. Certainly when we test the output trigger in Pattern Sequence mode, it looks like a trigger signal.

Here is a screenshot of the GUI when it is running in the mode we want:

One thing I was wondering about: we had to downgrade the MSP430 firmware so the device would operate after we removed the Light Engine. Not sure if this causes any problems?

Hi Jian Tay,

Downgrading the MSP430 firmware would not have an effect on the trigger. Your settings look correct so I'm going to need some time to see if I can recreate your problem to debug it further.

Do you have any additional information you can give me about your setup? What is your HDMI source? You mentioned that you removed the light engine, have you modified the LightCrafter in any other way?

Best regards,

Blair

Hi Blair,

The video source is coming from a graphics card on a computer. The card is an eVGA GeForce 210. Here's a screenshot of the current screen settings (I don't know why it says DVI-PC Display here, we are definitely using an HDMI cable and port):

Here's a plot of the signal I'm getting from the Trigger Out (Pin 3):

And one with a longer timescale:

The only modification we have done to the LightCrafter is to remove the Light Engine. We have a v2.0 board and have not added or removed any other components.

Hope this helps. Thanks again for your help!

Hi, Blair, I have a different issue wrg to displaying 1-bit mon picture via HDMI input -- could you please tell me what's the order of each color channel and bit will be displayed? I.e., will it bie Red bit0, Red bit1, Red bit 2... Red bit8, Green bit0, Green bit1... Green bit7, Blue bit0, Blue bit1, ... Blue bit7, or some other order?

Thanks.

Regards, Bing

Bing,

Typically if you're changing the topic, it is common courtesy to start a new forum post rather than taking over someone else's.

In any case, if you check the manual, the answer is Blue 0-7, Red 0-7 then Green 0-7.

http://www.ti.com/lit/ug/dlpu004b/dlpu004b.pdf (Page 56).

Sorry about that and thanks a lot for your help!

Hello Jian,

Please change the "color depth" to  24bit and then test. The HDMI Input expects the data in the RGB24 bit format. Your PC resolution shows that you are inputting much higher color depth 32bit. 

Regards,

Sanjeev

Hi Sanjeev,

Please see my previous forum post and the answer by Pascal: http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/850/t/277110.aspx

It is not possible to set the video card bit depth to 24. It goes as increments of 8, 16 and 32 bbp.

However, to quote Pascal:

I believe that this is correct, though I am not completely certain. I believe that 32 bit color is 24 bit RGB and 8 bit alpha (opacity or transparency). So, for the LightCrafter, 32 bit color should be identical to 24 bit RGB. It just ignores the upper 8 bit alpha channel.

Thanks.

Hi,

Just wondering if there was any progress on this question? Was it reproducible?

Thanks.

Hi Jian,

The DLPC300 still accepts the data in the RGB24bit format only. Although you are sending the data in 32bits per pixel the Alpha channel data is appears to be masked at the front-end DVI receiver chip TFP401A on the System Board, and DLPC300 receives data in 24bit format.

At this point the only option I suggest you to look at the video timing of the input signal. The max input pixel clock is 33.5MHz please check if it is within the specified pixel clock range. Also you cross check with the Parallel Interface Bus-Timing as specified in Table#8 and Table#9 of DLPC300 datasheet are within the specified limit.

If you have any standard video signal generator you can test it with also.

Regards,

Sanjeev

Hi Sanjeev,

Thank you for your reply. Please find my responses below.

Sanjeev said:

At this point the only option I suggest you to look at the video timing of the input signal. The max input pixel clock is 33.5MHz please check if it is within the specified pixelclock range. Also you cross check with the Parallel Interface Bus-Timing as specified in Table#8 and Table#9 of DLPC300 datasheet are within the specified limit.

Based on the settings (see screenshot below), the pixel clock is 32.0177 MHz. Please let me know if the other settings seem right to you.

I don't know where to test for the Parallel Interface Bus-Timing. Could you give me a test point, or point me to a schematic for the LightCrafter? I don't think it is possible to access the DLPC300 pins when it is running.

Sanjeev said:

If you have any standard video signal generator you can test it with also.

I'm sorry, but can you clarify what is a "standard video signal generator"? I would have thought that a video card should be adequate.

In any case, I am interested also to know if Blair managed to reproduce this issue last week.

Thanks.

Hi Jian,

I suspect the problem maybe caused by the VSYNC signal. I have not confirmed this, but I will test it hopefully later today or tomorrow.

Regards,

Blair

Hi Jian,

I apologize the delay, but unfortunately I haven't been able to perform the testing yet and won't be able to until next week. I will send you an update next week.

Best regards,

Blair

Hi Blair,

Thanks for the update. I look forward to hearing from you.

Thanks.

While I'm waiting for an update on this problem, I decided to test the LCr using the DM365 commands. One thing I've noticed is that the trigger output setting seems to be 'off':

i.e. reading command (0x04 0x04)

returns:

5, 4, 4, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 24

However, turning it on (setting payload bit 0 to 1) causes a 30 Hz trigger to be output. I wonder if the issue I'm seeing is something to do with a firmware bug?

Anyone successfully tested HDMI with ext trigger output correctly?

Hi Jian,

Sorry for the delayed response. I will have an update for you today or tomorrow.

Best regards,

Blair

Hi Jian,

I was able to look at your problem in more detail yesterday afternoon. First, you are correct that the trigger is not initially enabled. You need to enable it and set the pulse width and delay from the Pattern Sequence tab of the GUI. Second, we did see the 30Hz trigger you described at times and will be investigating this further. I will send you another update later this week.

Best regards,

Blair

Hi Blair,

Any word of a fix?

Thanks.

Hi Jian,

First, I apologize about the delayed response. It took longer than expected, but we were able to identify source of the strange 30Hz output trigger. We are currently testing the solution and will release a new software bundle as soon as possible.

Best regards,

Blair Conner

Hi Blair,

That's good news! It would really help us to get this fixed. 

I'm going to guess that it was an issue with the FPGA firmware, but can I also request that the LED cable disconnected fix (http://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/850/t/269160.aspx) be included in case we cannot use the updated file.

Looking forward to the update. Thanks!

Is there any update on a fix for this?

Hi Jian,

Sorry for the delay. The updated software should be released sometime this month. Not sure of an exact date yet.

Best regards,

Blair

Hi Jian,

Just an update on the software release. We're still working on some licensing details for the next release. We're trying to get it out as quickly as possible and I apologize for the delay.

Best regards,

Blair

Thanks for keeping me updated. Looking forward to it.

Hi Jian,

We have posted a new software bundle for DLP LightCrafter. Please install it and let me know if it solves your problems! It is available on the LightCrafter tool page (http://www.ti.com/tool/dlplightcrafter) in the "Available Versions" section. Please download version 3.0 for whichever operating system you are using on your computer.

Best regards,

Blair

Hi Blair,

Thanks! I'll test it and let you know of the outcome.

Great!  We had some hurdles to overcome while releasing the update, so thank you for being patient. 

Best,

Blair