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DM8168 EVM camera interface using TVP5147M1PFP decoder

Marcus Moore
Prodigy 130 points
Other Parts Discussed in Thread: TVP5147

Hi,

I'm currently undertaking a project whereby I will be making a small PCB to interface a composite video camera to the DM8168 evaluation module board for the purposes of doing some DSP later on. 

I'm using the TVP5147 decoder as the basis for the ADC board design, which takes the camera input through a BNC socket and outputs digital video to the EVM through high speed header(s) (QTH-xxx-01-x-D-xx), but am having some difficulty in confirming exactly which output pins from the TVP5147 need to be connected to which input pins on the EVM in order to capture 16-bit YCbCr 4:2:2 video with separate syncs on it.

So far I have established the following connections

TVP5147 DM8168EVM
HS/CS    VIN[0]A_HSYNC
VS/VBLK VIN[0]A_VSYNC
DATACLK VIN[0]A_CLK
GLCO/I2CA Pulled down to DGND
AVID VIN[0]A_DE
FID VIN[0]A_FLD

in addition to connecting the video input bus, but remain confused about the INTREQ output pin from the decoder - does this generate interrupts which will need to be serviced by the ARM cortex for video capture to work properly? If so, which input pin on the EVM should it be connected to?

As the I2C pins on the EVM are connected to a separate header from the video inputs, I am planning to breakout the SDA and SCL signals separately and crudely wire them to my board in order for the TVP5147 to be addressed as a slave and have its registers manipulated. However, according to the EVM schematic, some of the video input sync signals corresponding to the VIN[0]A_D bus are also connected to a separate header than the bus itself, which seems rather inconvenient. Is there a workaround for this or will I have to introduce a third HS header terminal into my design (one for video out, one for I2C breakout, one for sync signals)?

Would be extremely grateful for any advice you have on the matter!

Regards

Marc

  • 0
    TI__Mastermind 43875 points

    I can't comment much on the software side but I don't believe that the interrupt is necessary.

    Additionally I believe embedded sync mode is used so all the data signals and clock are available on J17.

    I2C is an issue though and does need to be routed from a different connector.

    One option for the I2C might be to jumper the I2C to J17 and use 2 pins which are nominally configured as DM inputs (so that they are not being driven). This would allow you to add only one connector. Using two connectors will provide better mechanical strength though.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Prodigy 130 points

    Thanks for the response.

    My understanding is that, in order to provide 16-bit YCbCr 4:2:2 video input to the EVM, I will have to configure the TVP5147 to output in 20-bit mode and use pins Y_[2:9] and C[2:9] (omitting the 2 LSBs of the chrominance and luminance signals). According to the output formatter control register(s) section of the TVP5147 datasheet, 20-bit output mode can only be used with separate syncs, some of which are connected to J17 of the EVM alongside the video input bus.

    Nevertheless, according to the schematic, the inputs VIN[0]A_VSYNC, VIN[0]A_DE and VIN[0]A_FLD are instead connected to J16. As far as I can tell the pin multiplexing facilities on the EVM do not extend to taking sync signal inputs for VIN[0] from alternate pins.

    Looking at the layout of the daughtercard however, it does appear that the TVP5147 is being used to output 16-bit video without the sync signals being connected separately. If this is the case and it is possible for me to use it in a similar fashion, or I've misunderstood the pin multiplexing and there is physical capability to take all sync signals over the J17 connector, would you be able to let me know how I can achieve this?

    Kind regards

    Marc

  • 0 in reply to Marcus Moore
    TI__Mastermind 43875 points

    I am checking into the embedded sync in 20 bit mode but in the meantime you could use 10 bit mode with embedded syncs.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Prodigy 130 points

    Any updates on this? The sync signals are the only part I don't have figured out yet.

    Thanks

    Marc

  • 0 in reply to Marcus Moore
    TI__Mastermind 43875 points

    20 bit embedded syncs is not supported by the TVP5147 so you will either need to use discrete syncs or 10 bit mode.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Prodigy 130 points

    I've decided to use embedded sync mode by incorporating a second connector into my PCB design, but can't seem to find information on the physical dimensions of the EVM - i.e. position values for where I will have to place the connectors on my board so that they lock together properly. Any advice on the matter?

    Best wishes,

    Marc

  • 0 in reply to Marcus Moore
    TI__Mastermind 43875 points

    Marc,

    You can find all documentation here...

    http://support.spectrumdigital.com/boards/evm816x/revg/

    The layout database is in Allegro format for which there is a free viewer available from Cadence. This should allow you to make any measurements you might need.

    BR,

    Steve