Serial interface for a vacuum fluorescent disply

[mojoe]

A few years ago, some of you acquired some Futaba or Noritake VFD's from me, a friend of mine, or elsewhere. At the time, I threw together an Arduino library (with some help from a forum member), to make the displays more useful. Recently, I was cleaning out some junk, and came across the displays.

These particular VFD's have a dumb 8-bit parallel interface, with no handshake lines. Only a Write Strobe is available, to tell the VFD it has a byte of data. Although the displays work fine, they require nine GPIO's in your project. I had a little time, so I thought I'd start on a simple serial interface.

I mention this in the program comments, but I'll say it again here: Do not try to power the VFD from the Pro Mini. It cannot source enough current. Power both the Pro Mini and the VFD from an external 5V supply. If you don't, your Pro Mini will release it's magic smoke.

The comments in the attached Arduino program explain why I chose to use a Pro Mini vs some alternatives. The attached picture shows the prototype, which is very simple. The photo also shows me testing the serial interface with an HC06 Bluetooth breakout board. Later, I'll make a board that plugs onto the 14-pin connector on the back of the VFD.

When I have more time, I'd like to use the Pro Mini to make the VFD emulate an HD44780 LCD, so you could use the standard Arduino LiquidCrystal library. Until then, I thought I'd post what I have now, so others can make use of it.

Edit: I meant to say a version of the LiquidCrystal library that is modified for serial output. The standard library only does 4 or 8 bit modes. Similar to the I2C version, but for TTL serial output.

[TomS_]

You could reduce pin count by using a shift register, like a 74x595. That would be only 3 pins: clock and data for the shift register, and the strobe for the display to tell it to load a byte.

That can be either hardware driven using a SPI peripheral, or bit banged in software.

[greenpossum]

Aren't there standard modules for a couple of bucks that have I2C input and have parallel outputs for piggybacking onto LCD displays? Could those drive the VFD board instead?

[edavid]

Did you find a datasheet for the VFD module?