Xpantastic!

Hi John,
 
I was thinking an entirely new display board would replace the old one, recieving the same signals the 4028's did on the old board.  It would be the same and shape as the old one.  It appears there's an address bus (LA on the schematic) that's decoded to drive the grids of each digit, and data bus to drive the segments.  An FPGA would be well suited to converting these signals to say, an async (UART) serial stream to ASCII display.  Like you said, it would recieve signals via the ribbon from the main processor.  Once the PC board was spun of course many copies could be made....
 
Those VFDs on ebay would have looked kind of cool...
Then I'd have the "Dot-Matrix-12" (yuk yuk)
 
Randy
 
R
 
--- On Mon, 8/4/08, John Pallister <john@...> wrote:

From: John Pallister <john@...>
Subject: Re: [xpantastic] Re: Noritake displays on ebay
To: xpantastic@yahoogroups.com
Date: Monday, August 4, 2008, 4:55 PM






Hi Randy,

I think you're right, and this is the only long-term 
solution for keeping otherwise-functiona l Xpanders going 
once their displays start to give out.

I suspect that actually fitting the adapter board and the 
new display into the very narrow space available would be as 
tricky as designing the interface.

An alternative would be to couple a new display with new 
firmware and a new daughterboard that received the ribbon 
cable to the display board and pulled out the (re-purposed) 
display signals; then the new firmware could drive the new 
display directly. This is obviously a lot more work, but 
there really isn't much space to fit anything between the 
case and the existing display board...

Cheers,

John :^P

William Cason wrote:
> 
> 
> Hi,
> 
> If absolutely necessary, I think a new display board could be created 
> for M12/Xpander that would decode the grid/anode signals to the original 
> VFD's and create the new signals to drive newer displays like the ones 
> on ebay the other day. This could be a simple lookup table and state 
> machine in an FPGA for example (I'm an FPGA designer). It would give an 
> opportunity for a slightly different display as well (e.g. VFD dot 
> matrix, 15 segment LED)
> 
> Does anyone know the failure rate of the VFD's (like ever?) Are they 
> one of the first things to go?
> 
> Randy

-- 
John Pallister
john@synchromesh. com