LVDS Example

[AtomSoft]

Hey guys i know what LVDS stands for but need help understanding it...

Low-voltage differential signaling - Wikipedia, the free encyclopedia

The above link doesnt help as much as i thought. Can some simplify this for me. Its for a Laptop LCD i have. I have the datasheet for it...

TM121XG-02L10 datasheet and Application Note, Data Sheet, Circuit, PDF, Pinout | Datasheet Archive

I want to use it in the near future (couple months) when i get my ARM or XMOS stuff...

I know a PIC/AVR wouldnt be able to handle it... so can someone please help me out... Thanks!

 

[Nigel Goodwin]

Basically it's similar to building (from scratch) your own video card, including writing all the software for it - and I'm dubious ARM will be fast enough?, I suspect custom hardware may be required?..

Loads of people keep trying to do something similar, but actual working results seem VERY rare.

LVDS is just the connection, a very high speed one using differential twisted copper pairs, and you will need to create that at your end.

 

[AtomSoft]

wow seems like mission impossible for me heh... might as well sell the LCD panel and buy a normal TFT LCD with a NON LVDS interface

 

[JimB]

OK, a few disconncted ideas to try and put you on the right path.

LVDS is a HARDWARE protocol, it defines the electrical connection.
It defines voltages, and line impedances.

Look at this link to some LVDS line drivers and receivers:
https://www.electro-tech-online.com/custompdfs/2010/08/slld009.pdf
it may help.

It does NOT define the data which is passed through the LVDS connection.


An example.
Say I want to send some date between two devices, I want to send the data at a fast rate over a long distance.
I decide that LVDS line drivers and receivers will do the job if I use a suitable twin twisted cable between them.

Device 1 which is doing the sending, I program this to send the data out of a digital I/O port pin, I am sending 1s and 0s, 5v and 0v.

Device 2 which is doing the receiving, I program this to read the data in from a digital I/O port pin, I am receiving 1s and 0s, 5v and 0v.

I can connect the output pin from device 1 to the input pin of device 2 and they will communicate across the bench.

Once I have this working, I can move the devices apart, connect an LVDS driver to the output pin of device 1, connect an LVDS receiver to the input pin of device 2, and finally connect a cable between the LVDS driver and receiver.

With a bit of luck my devices will communicate again, even though they are now a long way apart.

I hope this simplistic description has cleared the fog for you!

JimB

Afterthoughts

The data which is passing from device 1 to device 2, could be as simple as asynchronous serial data, 1 start bit, 8 data bits and 1 stop bit. Just like good old RS232 ASCII.

Or, it could be just a stream of bits. I which case I may need a second LVDS path carrying a clock, so I know where one bit starts and the other ends.

 

[AtomSoft]

Thanks i have to read that PDF ...

 

[Ubergeek63]

Hey guys i know what LVDS stands for but need help understanding it...

Low-voltage differential signaling - Wikipedia, the free encyclopedia

The above link doesnt help as much as i thought. Can some simplify this for me. Its for a Laptop LCD i have. I have the datasheet for it...

TM121XG-02L10 datasheet and Application Note, Data Sheet, Circuit, PDF, Pinout | Datasheet Archive

I want to use it in the near future (couple months) when i get my ARM or XMOS stuff...

I know a PIC/AVR wouldnt be able to handle it... so can someone please help me out... Thanks!

Pay no attention to the self proclaimed wizard behind the curtain, the way to make it work is https://www.electro-tech-online.com/custompdfs/2010/08/sn75lvds83b.pdf or something similar.

4 7 bit parrallel ports (plus a clock) in and LVDS out.

and you need a full LCD driver as well to keep the display refreshed, though you might be able to dog an ARM to put up basic images if you have a DMA peripheral on chip.

 

[AtomSoft]

wow thanks! I might use a xmos since i can have tons of IO and 8 threads on a core.. meaning i can max out a couple threads on this and still have enough power to do processing of images and stuff. With a 4 core i can build this no problem heh

 

[Ubergeek63]

wow thanks! I might use a xmos since i can have tons of IO and 8 threads on a core.. meaning i can max out a couple threads on this and still have enough power to do processing of images and stuff. With a 4 core i can build this no problem heh

NP, tis the difference between one who is reading theory and one who is working with the crap!