BTW, it's also a 2-board design, like that mentioned here about 2 months ago,..., but with upto 3 meters screened cable between the 2 for power & data (TTL serial).

Hallo Richard,

I know, that some LCD modules are very sensible at 'enable' input! If here the edges are not fast enough or the timing is degraded in any way, trouble will occur...

If you use 3m long cable without drivers and buffers a relevant smoothing of edges can occur. So, you will need some additional circuitry to guarantee that timing isn't degraded, when signal runs over your cable.

Crosscoupling between the wires can also make trouble.

And does you driver matches the characteristic impedance of cable? What kind of termination do you use?

The EMC issue can be solved, when the cable and the LCD modul have a screen, which work as a Faraday cage. The task of Faraday cage is to provide a way for ESD events, making it impossible for them to penetrate your application. For this, Faraday cage must not be interrupted relevantly.

Another measure to deal with EMC is to feed all the cable wires through a common mode ferrite choke (ring core for instance), where the cable is connected to your microcontroller circuit.


Kai