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TFP401 HDMI/TTL Pixel Clock Signal
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TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Sat Mar 11, 2017 7:19 am

Hello,
I am not able to get the TFP401 board working and getting some weird signal on pixel clock output
Max: 1.88V
Min: 1.44V
Amplitude: 0.439V
Freq: 2.66Khz (not stable)

Measured on TFP401 between GND and PIN44 (ODCK), with power supply connected and HDMI cable plugged in (screen 800x480 was detected by computer).
It seems to be wrong. Could somebody check this please?
HSYNC, VSYNC, DE seems to be correct.
Last edited by MatGO on Mon Mar 13, 2017 2:14 pm, edited 1 time in total.

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by adafruit_support_rick on Sat Mar 11, 2017 9:21 am

Can you post some pictures of your setup? Wiring, soldering, etc.

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Sat Mar 11, 2017 10:01 am

I am getting that pixel clock signal also when the output is disconnected.
This is how the pixel clock signal was measured
Screen setup:
Resolution: 800x480
Colors: 32bit (16bit are optional)
Refresh rate: 66hz (no other options)

Circled part is getting really very HOT! Is it ok?

Image

I am really not happy you have to see this, but here is my target setup (proof of concept) at this moment
Trying to connect to the GVIF transmitter. The target board was modified and all inputs on transmitter are free of any another connection.

Image

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by adafruit2 on Sat Mar 11, 2017 3:36 pm

if you dont have a backlight connected, yes the diode will get hot. its not designed to run an FPGA board or whatever you have there, its designed for a TFT screen

you can see our schematics here
https://github.com/adafruit/Adafruit-TF ... in-TFT-PCB
note that there's no *firmware* on the device, its completely self-contained hardware, so the performance matches the datasheet. we test each one with a TFT before shipment!

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Sat Mar 11, 2017 4:48 pm

I am sorry, my mistake. I figured out that my oscilloscope is up to 20mhz only, not more as I guess, so it can be the cause of wrong signal measured.

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Mon Mar 13, 2017 2:11 pm

I got GVIF transmitter working with TFP401 - I am able to transfer whole TTL signal via GVIF to receiver chip.
The problem is I am still not able to get image on the screen connected to receiver (Receiver is OEM Car Head Unit with some unknown 800x480 Toshiba LCD)
I guess it is caused by different clock settings.
I measured correct signal from OEM unit and it differs from what I am sending via TFP401.

Could somebody help me how I can compute or recover correct setting from measured signal and generate propper EDID data?
Last edited by MatGO on Mon Mar 13, 2017 7:32 pm, edited 1 time in total.

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by adafruit2 on Mon Mar 13, 2017 2:16 pm

the refresh/clock is *completely* set by the source, you can google around for "EDID generator" (theres some for every platform including perl scripts :) and then burn it into the EEPROM whenever you like.

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Mon Mar 13, 2017 7:31 pm

I've got it, it is working now :) The clock settings were completely different.
Just another question.. Color depth on LCD seems to be a bit limited. Is it also about some setting or it may be limited by LCD?

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by adafruit2 on Mon Mar 13, 2017 7:48 pm

*shrug* its 24 bits output or whatever the computer is set to

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by 50cmd on Fri Nov 02, 2018 1:36 am

MatGO wrote:I got GVIF transmitter working with TFP401 - I am able to transfer whole TTL signal via GVIF to receiver chip.
The problem is I am still not able to get image on the screen connected to receiver (Receiver is OEM Car Head Unit with some unknown 800x480 Toshiba LCD)
I guess it is caused by different clock settings.
I measured correct signal from OEM unit and it differs from what I am sending via TFP401.

Could somebody help me how I can compute or recover correct setting from measured signal and generate propper EDID data?


I collect a similar adapter. I plan to convert HDMI to GVIF. How do you transform, can you look at your decision? Can you help me with GVIF transmitter?

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by tkolody on Fri Dec 28, 2018 2:45 pm

Any chance you'd be willing to share the timing/config/edid that worked?

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by MatGO on Fri Dec 28, 2018 3:20 pm

I dont remember at all but found some files in my project folder. Let me know your email.

https://youtu.be/c1wd1S78VyI

2017-03-07 21.10.44.jpg
2017-03-07 21.10.44.jpg (179.69 KiB) Viewed 125 times

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by tkolody on Fri Dec 28, 2018 4:02 pm


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Re: TFP401 HDMI/TTL Pixel Clock Signal

by 50cmd on Wed Jan 02, 2019 6:54 am

MatGO wrote:I dont remember at all but found some files in my project folder. Let me know your email.

Hi! My mail 50cmd@inbox.ru. Thanks!

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Re: TFP401 HDMI/TTL Pixel Clock Signal

by ethicaldesign on Tue Jan 08, 2019 12:11 pm

MatGO wrote:I dont remember at all but found some files in my project folder. Let me know your email.

https://youtu.be/c1wd1S78VyI

2017-03-07 21.10.44.jpg


Can you email this to me as well? I'm working on the same project!

brett.schenck@wilkes.edu

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