I am using an Arduino Mega as a controller for a high power Ham radio amplifier, so the Arduino and the LCD are operating in a very high RF environment.
It works perfectly on most frequencies but on a higher frequency the LCD starts displaying "garbage" and I can't get it to clear up without rebooting the Arduino Mega. I am using a 4x20 LCD using i2C. I have tried at time intervals clearing the LCD and printing a new template to the LCD but it doesn't clear out the garbage. The other functions of the controller still operate, so I am pretty sure the Arduino is still functional.
I am pretty sure that I could clear the problem with additional shielding and bypassing, but that would be a lot of work as it is not easy to get at the LCD when it is in the amplifier cabinet.
As anyone seen this type of LCD display and is there a way to clear out the LCD display short of restarting it?
dsolberg:
I am pretty sure that I could clear the problem with additional shielding and bypassing, but that would be a lot of work as it is not easy to get at the LCD when it is in the amplifier cabinet.
I do have a quit same problem with my VFD 20X4 characters from NORITAKE CU20045-UW4J display.
I do use it not in a RF environment or something others.
I have build a K3NG CW keyer witch is on the workbench now.
Somethimes all characters a coming black (whole VFD window) and oter times I receive a lot of
garbage and after a while everything is announced like it should be ??
Question those there excist 14 pins I2C backpacks for this kind of displays ?
Most backpacks are for 16 pins displays types ?
Why this question :I will make a try with I2C communication to see if it betters ??
There must be something that destroys the circulated data between ARDUINO MEGA 2560 and this display
Maby wrong circulated data information between both of them ?
I hope someone could my pointing out in the good direction.
This whole K3NG project works like great,just this little remarcable fact !!!
on4aef:
Question those there exist 14 pins I2C backpacks for this kind of displays ?
Most backpacks are for 16 pins displays types ?
The 16 pin backpacks allow for the LED backlight on LCD displays; pins 15 and 16.
A VFD display is self-lighting - but takes a lot more current - and has no contrast "ladder" controlled by "Vo" - pin 3, so pins 15 and 16 are unnecessary. If the pin functions on the VFD display correspond to pins 1 to 14 on the backpack, and the display functions in 4-bit mode, then the backpack will work fine so you can use the common backpack
on4aef:
Why this question :I will make a try with I2C communication to see if it betters ??
Possibly. Make sure you have a large capacitor (1 mF or so) across pins 1 and 2 of the display - and that your 5 V power supply is adequately rated. Obviously you cannot use the on-board regulator of the Arduino to provide 5 V to a VFD display.
Thanks Paul for the information around the backpack setup
Yes I do had buyed a backpack also for my VFD.
But I saw that the pin row does not correspond,so I decide to not used it yet !!
But anyway if I want I can used use if all other pins configurate from 1 to 14 great ...
About the garbage I have somethimes,I do have only 10µF across pins 1 and 2 ?
I always can try to connect a bigger one 100µF or so ?
The +5VDC supply is not the question,its all arrive from a external build power supply with
a current rating of about 2A or so ...more than enough hi ..
I will do next days again somes tests concerning the VFD dispaly readout.
I think it all works a lot better by means of I2C use;not ???
Maby I don't have this garbage anymore ?
Well, I did suggest a bigger capacitor again - a 1 mF, but 100µF should be fairly effective. The suggestion is that if the display presents a heavy load to the power supply, there may be transients on the wiring. This has often helped with LCD displays being corrupted by inductive impulses from relays and motors.
