How to reduce a noise reaching uC via a flat cable?

[ZeleC]

bus noise

helllo
im having problems with noise accross the flat cable of my uC, the flat cable is attached to a lcd . im not having problem with information to reach the lcd , everything here is good , but the problem comes with my uC , its going crazy , im thinking of transient developing across the flat cable,and i have to use a certain lenght so i can not shorten the length.

what is the best solution for reducing this noise thaat is reaching the uC via the flat cable
thx in advance for ur help

 

[MonkeyBusiness]

Re: bus noise

Assuming your uC drives the flat-cable directly, it may pick-up RFI. The solution to this will be to insert some filtering (RF blocking beads for example) between the uC and the cable. You can also insert digital drivers, these will probably solve the problem as well.
It is also possible that your uC has trouble in driving the cable, in which case the solution with the drivers should do the trick.

 

[Aoxomox]

Re: bus noise

try introducing some 50 - 100 ohms series resistance in each dataline on the MCU side of the cable.
But normally this should not make a MCU go crazy, except your ground design of the PCB is poor. if there are any cirtical components like reset generator or oszillator close to the flat cable connector try stabilizing them with capacitors.

 

[bunalmis]

Re: bus noise

Did you use gnd for all even number of flat cable.

signal1, gnd1, signal2, gnd2, signal3, gnd3 ......