intermittent weird behavior with 1602 LCD

[Alberta2012]

Hi everyone,

I made a design, that uses a 1602 LCD.

wrote the program for an ATTiny4313, and it works perfectly ...most of the time...

Sometime, and I could not identify a common pattern, the display shows garbage: I mean by that, bunch of illogical caracters, filling up the whole display.

If I try to reset the display, using "displayClear" it does not do any thing..... the only solution is to cycle power....

I'm using 6 I/O lines for my LCD. they are connected directly from the CPU to the LCD. one of my "suspect" is that noise might get induced to the data line...

do you think that some pull-down resistance might help ?

any other idea ?

[Benj]

Hello,

Instead of calling the clear function try calling the start function as this should re-sync the communications if they are getting out of sync as well as clear the display.

Is the display on a ribbon cable or on a cable? If so then can you reduce the length of the cable at all?

[Alberta2012]

Hi Benj

connection is made with 6x individual cable, about 6-7 inches of length...do you think it can be an issue ? I could probably shorten then by 1-2 inches

what about the idea of placing a pull-down resistance ? could it help ???

I will modify my code to do a Start as suggested and let you know if there is any improvement

[Alberta2012]

correction: 9 x individual cable (including Vcc, Ground, and backlight)

[Benj]

Hello,

Reducing the cable length should help a bit and it should be possible to terminate the far ends using resistors and caps to overcome any transmission line issues.

This discussion looks interesting.
http://www.edaboard.com/thread304286.html