Hi,
we are planning to connect a 4.3 inch RGB TFT Display like
https://www2.mouser.com/ProductDetail/Newhaven-Display/NHD-4.3-480272EF-ASXP?qs=MyNHzdoqoQLPUrqKOKliMA%3D%3D
to a microcontroller with a cable of a length of 1 meter.
Do you have any suggestions how make this possible with a low cost solution?
We were thinking of converting the signals to FPD Link and back to parallel, but the FPD cables and connectors seem very expensive.
Another idea was converting the signals to HDMI, but this would require to pay license fees.
Can you think of another cheaper solution for consumer products?
Thanks in advance,
Sopho
Look at the controller datasheet:
https://support.newhavendisplay.com/hc/en-us/article_attachments/4414852703383Page 46 has the timing specs for RGB operation. For parallel RGB mode, the maximum clock is only 12MHz. That’s not particularly high, and there’s a decent chance it’ll just work on quite ordinary wiring. Even the serial RGB mode (i.e. 8 data lines, RGB bytes sequential) is just a 30MHz clock maximum. The signaling types you’re looking at are for multi-Gbps signals. Yours isn’t even remotely close to that.
Page 74 has the corresponding bus timing diagrams.
I just hooked up a square wave from my old, 12MHz max function generator. The pink trace is the signal via a 1m BNC cable. The yellow trace is through over 3m of 24AWG speaker wire, just ordinary untwisted twin wire. No shielding. One picture shows 5MHz, the other 12MHz. Is it pretty? No. Is it good enough to probably work flawlessly? Yes.
The key will be to properly terminate the bus to eliminate reflections. You don’t need to resort to differential signaling (though you certainly could). You could use single-ended line drivers. Regardless, proper termination should make it work.
Before doing anything more complicated, I’d try using your normal signals over simple ribbon cable (which has around 100 ohm impedance), with pads for terminator resistors.
(In the test setup, the output is split at the function gen, with a 50 ohm terminator, and then each scope input also has a 50 ohm terminator, but who knows what that cable’s impedance was!)