Help Understanding TMDS - Dom Needs Your Help!

  • Thread starter Severence
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In summary, the Sil150A TMDS transmitter/encoder has pins for red, green, and blue to deliver the same 8 bit value at the same time which would give 1-pixel clock input mode.
  • #1
Severence
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Hi my names Dom, just joined the forum and look forward too getting to know you other members.

Hopefully I've posted this in the right section.

I'm struggling to understand a TMDS datasheet and was hoping someone with a bit more know-how could help me out (draw it in crayons for me) :D

I have a source device that outputs three 8bit serial RGB lines as well as clock, Hsync and Vsync. I've read through the datasheet for a SIL150A TMDS transmitter/encoder and the pinout is confusing me.

Untitled.jpg


If i understand it correctly (unlikely) my serial 8 bit red signal would go to DIE23 Pin 90, green to DIE15 pin 99, and blue to DIE7 Pin 9 and this would give me 1-pixel clock input mode? input clock, HYSNC & VYSNC all seem pretty self explanatory to hook up (although I'm probably wrong about that too)

If the above is correct? what are the outputs to the corresponding inputs... for a DVI setup for example, is it TX1+ etc?

Thanks in advance to anyone who can help out.
 

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  • #2
Edit: above, seems as though the transmitter above can only output analog (i think) and not digital, hdmi, dvi which is what I'm after, but the same principles apply to other TMDS transmitters such as analog devices ADV7513
 
  • #3
Severence said:
I'm struggling to understand a TMDS datasheet and was hoping someone with a bit more know-how could help me out (draw it in crayons for me) :D

I looked at the datasheet and it's pretty self-explanatory. :uhh:


Severence said:
If i understand it correctly (unlikely) my serial 8 bit red signal would go to DIE23 Pin 90, green to DIE15 pin 99, and blue to DIE7 Pin 9

No, the inputs are parallel. You have to deliver the entire 8 bits for each colour at the same time (so for red you place a 8 bit value at DIE16-23. Check the Input Pin Description section in the datasheet PDF (p.4).

Severence said:
this would give me 1-pixel clock input mode?

No, PIXS held LOW sets 1-pixel mode.

Severence said:
what are the outputs to the corresponding inputs... for a DVI setup for example, is it TX1+ etc?

I don't know much about TDMS but it looks like it uses 4 differential pairs - TX0+/-, TX1+/-, TX2+/- and TXC+/- for transmission.
 
  • #4
Severence said:
seems as though the transmitter above can only output analog (i think) and not digital, hdmi, dvi

The output is a digitally modulated signal, so the result is analog. That's Digital Communications 101.
 
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  • #5
Thanks for your resposne, youve been a great help.

I'll have a bash at it and report back :)

cheers.
 

What is TMDS?

TMDS stands for Transition-Minimized Differential Signaling, and is a method used to transmit digital video and audio signals between devices, such as a computer and a monitor.

How does TMDS work?

TMDS works by encoding the digital data into a series of voltage levels, which are then transmitted over a cable to the receiving device. The receiving device then decodes the voltage levels back into the original digital data.

What is the purpose of TMDS?

The purpose of TMDS is to ensure a high-quality, reliable transmission of digital video and audio signals between devices, without any loss or degradation of data.

What are some common issues with TMDS?

Some common issues with TMDS include signal loss or degradation due to a poor quality cable or interference, compatibility issues between devices, and incorrect settings or configurations.

How can I troubleshoot TMDS issues?

To troubleshoot TMDS issues, you can try using a different cable, checking for any interference, making sure the devices are compatible, and adjusting settings or configurations. You may also need to consult the user manual or contact the manufacturer for further assistance.

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