Interfacing VFDs and Keypads with PIC18F258

[Rachna]

:!: Hi There,

I have recently started using the PIC18F258 microcontroller. I Would like to know that how can i interface this microcontroller with a VFD display and a Keypads. Please Help !

Regards,
Jas.

 

[FoxyRick]

Hello Rachna,

VFD's come in three types to me:

1. Types with an interface compatible with common LCD's
2. Types with another interface
3. Types with no interface (bare VFD tube with lots of connections)

(Note - these 'types' are just *my* way of thinking - don't go asking for a 'type 1' vfd - they won't know what you mean)

Type 1 is the most easy to use, and many are now like this. Look for ones compatible with the HD44780 chip found on many LCD's. This way, you can use the already written code found on this board and the web, without having to reinvent it all.

Type 2 can still be quite easy, These are the main ones I tend to have around because they are cheap surplus. You will need to write your own code, or modify standard code to use them. I have some with a nice serial interface - dead easy to just convert from RS232 from a PC or just use the serial port directly from a PIC.

Type 3 are tougher and need extra parts to drive them. I have a box full of these. They too can be simple though, just like driving a multiplexed LED display as far as the software goes. They need a voltage inverter and driving logic capable of handling their voltages.

Use type 1 or 2 in that order

You don't say what language you use, but here are a few links that might help. Also try searching this board. You will find more if you search for LCD code than for VFD.

http://home.iae.nl/users/pouweha/lcd/lcd2.shtml
**broken link removed**
**broken link removed**

If you can tell us what VFD you want to use (manufacturer, part number) we can give more help about how to interface it.

Keypad interfacing is usually done by scanning rows/columns and looking for a keypress. Debouncing is one thing to check for - switches do switch cleanly and give lots of false on/off/on events that a micro is fast enough to see. It must be programmed to ignore these short pulses.

http://www.mikerj.clara.net/
http://jap.hu/electronic/codelock.html

Hope this helps,
FoxyRick.

 

[kRoy]

I'd rather you use an OLED display instead of VFD. OLED display is cheaper, does not produce heat and not as sensitive as the VFD is.