This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DLP5531-Q1: DLP Input over HDMI and its specifications ?

Part Number: DLP5531-Q1
Other Parts Discussed in Thread: DLPC230-Q1

Hi, 

Recently I saw TI's DLP Headlight Demo, where DLP Headlights can projects zebracrossing, Left Turn and many more signs on road surface while driving. And as per my understanding , DLP works as projector, whatever input we provide over HDMI, DPL will project it. 

I have few queries

1. Input video over HDMI should be 60 fps? 

2. Can we input 1 fps or 30 fps video data as well? 

3. If we can not input low fps video? How to convert it to 60 fps? 

4. Input video over HDMI should be of 1152 × 576 resolution?

5. Can we feed 1280x720 or Full HD resoltion video directly to DLP over HDMI?

6. Input should be in RGB Planar/interleaved or YUV format?

Regards,

Sagar

  • Hi Sagar,

    I'm glad you had an opportunity to review what a headlight using DLP technology is capable of. I'll answer your questions below.

    Thanks,

    Jake

    SagarK said:

    1. Input video over HDMI should be 60 fps? 

    Yes, this is correct. The DLPC230 supports three video modes as described in the datasheet (http://www.ti.com/lit/ds/symlink/dlpc230-q1.pdf) Section 7.2.1 - Table 4. All three video modes are at 60Hz

    SagarK said:

    2. Can we input 1 fps or 30 fps video data as well? 

    No, the only available mode is at 60Hz. Can you tell me what the reason would be for the lower frame rate, especially a 1Hz update rate?

    SagarK said:

    3. If we can not input low fps video? How to convert it to 60 fps? 

    I'm sorry but content generation is outside the scope of what we can help with. I'm sure there are many utilities available for creating content at 60Hz.

    SagarK said:

    4. Input video over HDMI should be of 1152 × 576 resolution?

    There are three supported resolutions: 1152 x 576, 1152 x 1152, and 576 x 288. However the default resolution of 1152 x 576 is typically easiest to work with.

    SagarK said:

    5. Can we feed 1280x720 or Full HD resoltion video directly to DLP over HDMI?

    No, with this evaluation module it is not possible.

    SagarK said:

    6. Input should be in RGB Planar/interleaved or YUV format?

    Input should be RGB. Since the headlight is monochromatic the only color channel used by the EVM is the red channel. Other data on the blue and green channels is discarded.

  • Hi Jake,

    Actually algorithm output is at les than 60 fps. So, I want to make sure whether DLP will accept low fps input or not ?

    Also I have one more doubt related to pixel frequency:

    I am referrring to DLPC230-Q1 Automotive DMD Controller for the DLP553x-Q1 Chipset Datasheet. ( Section 7.2.1 Supported Input Sources )

    For 1152x576 resolution, How pixel clock is calculated as 44.426 MHz.

    Can you share exact formula to arrive at 44.426 MHz?

    According to my calculation as per formula,

    HActive = 1152

    VActive = 576

    Frame rate = 60

    Blanking =  sync + back porch + front porch = 8 + 14 + 3

    this gives Pixel Clock as 49.76 MHz

    Reagards,

    Sagar

  • Hi Sagar,

    The default configuration of the DLPC230 will not accept frame rates below 60Hz. The three supported source resolutions are described in the table you referred to above (Table 4. section 7.2.1). If the frame rate is too low we would expect that there would be noticeable flickering which is typically unacceptable in headlight applications. There is some software flexibility though so if a lower frame rate is absolutely required it may be something we could evaluate.

    For calculating the pixel clock it is:

    (total horizontal pixels) x (total vertical lines) x (frame rate)

    where the total horizontal and vertical resolutions include the blanking. So for your example (from table 4):

    Total horizontal blanking = 80

    Total vertical blanking = 25

    Horizontal active pixels = 1152

    Vertical active pixels = 576

    (1152 + 80) x (576+25) x 60 = 44.426 MHz

    Best Regards,

    Jake Pulliam