DLPLCR67EVM: Single-pixel control and pattern on-the-fly limits

Dimitar Boev

Part Number: DLPLCR67EVM
Other Parts Discussed in Thread: DLPLCRC900DEVM, DLPC900, DLP470TEEVM, DLPC7540EVM, DLP670S

Dear TI DLP Experts,

we are looking for a DMD EVM that can cover these requirements:
- fast and easy control of single pixels (completely on or off, ie binary) with a PC/laptop
- arbitrary patterns in real time (or minimum 1000 pre-stored patterns (is adding external memory an option?))
- high pixel density and small pixel pitch size

We have found DLPLCR67EVM has high pixel density, but we are not sure if we can control single pixels and arbitrary patterns.
Our application is towards 3D printing.

Looking forward to your reply!

With warm regards,
Dimitar

4 months ago

0 Tristan Bottone 4 months ago

TI__Prodigy 640 points

Hello Dimitar Boev,

Thanks for reaching out and using the E2E Forums! I have assigned this thread to someone more familiar with this platform, and we will look into this as soon as possible.

0 Michael Ly 4 months ago

TI__Expert 3790 points

Hi Dimitar,

The DLPLCRC900DEVM is meant to be paired with the DLPLCRC67EVM. On the product page of the DMD EVM, it says that this DMD board can reach 1-bit pattern rates up to 9,523-Hz.

I would recommend using the video or video pattern mode to define frames based off exposure time. If you require a longer exposure time, you may repeat a pattern in the next frame until you reach your exposure time.

If you wish to use a pre-stored pattern mode, that could work as well if you know all your slices ahead of time. The downside with that is the total amount of images stored, which is a maximum of 400 binary images.

Does this help or give any additional insights? Please let us know!

Thank you,
Michael Ly

0 Dimitar Boev 4 months ago in reply to Michael Ly

Prodigy 30 points

Hello Michael,

thank you for the information!

Does this mean that this EVM allows for 9,523 frames per second using binary images?
I suppose this would be possible only through the pre-stored pattern mode, as the USB/HDMI(?) would be limited by the transfer rate of data?
Looking forward to the reply!

Best,
Dimitar

+1 Michael Ly 4 months ago in reply to Dimitar Boev

TI__Expert 3790 points

Hi Dimitar,

Here is a text file I created some time back that helps explain the DLPC900 operating modes. If you do not have a markdown viewer, you may open the file with any text editor such as notepad, VSCode, Vi, or whatever you decide to use.

Notes_OperatingModes.md

DLPC900 Operating Modes
================================================================================

Video Mode
============================================================

* Not pixel-accurate
* Unlimited amount of data can be streamed
* 24-bit RGB input up to 120 Hz
    - The DLP LightCrafterTM EVM maximum video rate is limited to 60 Hz by the
      video receiver chip

Video Pattern Mode
============================================================

* Pixel-accurate
* Unlimited amount of data can be streamed
* 24-bit RGB input up to 120 Hz
    - The DLP LightCrafterTM EVM maximum video rate is limited to 60 Hz by the
      video receiver chip

Pre-Stored Pattern Mode
============================================================

* Pixel-accurate
* ~45 MB flash memory can be allocated for pattern storage
* 9.5 kHz (1-bit)
* 1031 Hz (8-bit)
    - The 8-bit pattern rate uses an illumination modulation technique. Without
      this technique, the 8-bit pattern rate is 247 Hz

Pattern on-the-fly Mode
============================================================

* Pixel-accurate
* DLPC900 internal memory suports up to 400 unique 1-bit images
* 9.5 kHz (1-bit)
* 1031 Hz (8-bit)
    - The 8-bit pattern rate uses an illumination modulation technique. Without
      this technique, the 8-bit pattern rate is 247 Hz

# Pattern Data Flow for the Operating Models

Video Pattern Mode
============================================================

* Video Data Source streams data into the system.
    - This device must be present the entire time patterns are being displayed
* Video receiver chip will convert incoming HDMI or DP data into parallel RGB
  data used by the DLPC900

* FPGA only required when using Dual C900 configuration for the DLP9000

* The DLPC900 will apply the user's pattern configurations when diplaying the
  data on the DMD

Pre-Stored Pattern Mode
============================================================

* Host loads a FW file containing up to 45 MB of compressed patterns into the
  flash memory

* Once the patterns are loaded into the flash, the host can be removed

* These patterns will remain in flash even on power-down

* The user can then select a subset of these patterns to load into the
  DLPC900's internal memory

* These patterns with the user's configuration will be displayed on the DMD

Pattern On-The-Fly Mode
============================================================

* Host will pattern data directly to the DLPC900's internal memory via USB

* The DLPC900 can store up to 400 1-bit patterns or 50 8-bit patterns in its
  internal memory

* Once the patterns are stored on the controller, they can be sent to the DMD
  for display

There is one caveat if you use the EVM or the IT6535 video receiver we use on our DLPC900 EVMs, however: This is mentioned in the notes. Only 60 Hz video is supported because of this. Your assumption of transfer rate of data is correct.

The 9.5 kHz frame rate applies to pre-stored pattern mode and pattern on-the-fly mode. This confirms your other assumption!

Does this help you come to a decision? Is there anything else you would like to know before you move forward?

Thank you very much,
Michael Ly

0 Dimitar Boev 4 months ago in reply to Michael Ly

Prodigy 30 points

Dear Michael,

thank you very much! This is a nice explanation and helped me a lot.

Is it possible to transfer 1-bit images via the HDMI/DP and if not, then why not?
We currently have the DLP470TEEVM/DLPC7540EVM and when using the HDMI I think the black colors still emit some light no matter how much we adjust the images.
It could be that we do something wrong too, but from what i have read that DMD has a different application behind it and does not allow for pixel-accurate modes.
We want to get rid of that (which i assume is the pixel-accurate 1-bit mode) and also achieve a bit higher framerate (even though 120/240/450 Hz should suffice).
Is there another type of DMD/controller that can do that or something similar?
The 400 pre-stored images is already great, but we might have some use-cases where we need more than that.

Thanks again for all your help!

Best,
Dimitar

+1 Michael Ly 4 months ago in reply to Dimitar Boev

TI__Expert 3790 points

Dimitar,

You are very welcome!

Dimitar Boev said:
Is it possible to transfer 1-bit images via the HDMI/DP and if not, then why not?

It is indeed possible to use binary patterns via HDMI/DP if you use Video Pattern Mode (which I will call VPM for ease for the rest of the thread). When using VPM, you can define the bit depth (1 through 8), the exposure time, and the dark time. The DLPLCRC900DEVM's user guide might be a good place to look. You can go through it in the "Virtual Connection" mode of our reference software GUI to get a feel for how this works. The link to the DLPC900 LightCrafter(TM) GUI is located here.

Here is an example of choosing bit depth:

And another showing an option for exposure and dark time:

We also have a programmer's guide that allows you to do things not implemented or exposed in the GUI. This will give you the best control if you choose this device and go for a customized build for your application.

Dimitar Boev said:
We currently have the DLP470TEEVM/DLPC7540EVM and when using the HDMI I think the black colors still emit some light no matter how much we adjust the images.

These devices The DLP470TEEVM / DLPC7540EVM are on the Display side of DLP(R) products, and we would not recommend you use these, as they are not optimized for pixel-accuracy as you have described.
We recommend you look into our Light Control products (Such as the DLPLCR67EVM / DLPLCRC900DEVM) instead. Here is a link that will point you in the right direction: https://www.ti.com/dlp-chip/overview.html

Depending on your budget, you may also be able to view DLP Pico products as well.

What kind of 3D printing applications did you have in mind? Will this be geared more toward small applications (such as desktop) or something industrial? This will help narrow down some options for you if you do not feel the DLP670S is the right decision.

I'd be happy to talk to you about this more or get you in contact with someone from DLP Pico if you go that direction!

Best regards,
Michael Ly

0 Michael Ly 3 months ago in reply to Michael Ly

TI__Expert 3790 points

Hi Dimitar Boev,

Do you still require assistance, or do you need a little more time to look into these products?

Thank you,
Michael Ly

0 Dimitar Boev 3 months ago in reply to Michael Ly

Prodigy 30 points

Hello Michael,

thank you so much for the thorough explanation!
Yes, this definitely helps me and and we can make the decision from here on.
I have checked the DLP Pico products and unfortunately they have a smaller than desired number of pixels.
I think the DLP670S to be better.

Thank you,
Dimitar

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DLPLCR67EVM: Single-pixel control and pattern on-the-fly limits