Author Topic: Serial VFD to TI-83+  (Read 2067 times)

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Offline MGOS

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Serial VFD to TI-83+
« on: May 23, 2013, 07:39:03 am »
Since I got my large LCD working with the 83+ I've been looking through old electronics and parts I had and found some VFDs by NEC (looks like early 90s, maybe even late 80s). In case you don't know VFD stands for vacuum fluorescent display. They were used in e.g. calculators, audio equipment and automobiles. Today, most of them are replaced by the much cheaper LCDs, but they look awesome and are readable from any angle :)
So I figured out how to hook them up to an arduino, which was really simple because of its built-in serial interface. You can control everything just with one wire and ground. Well, that should make it possible to use it with the link port of the 83+, right? I wrote my own Axe routine to transmit Data serially at about 9600 baud (it works, that is everything that counts :P). It was a lot of trial and error and I had to try out a lot of different delay values to make it work.

The display has an external power supply (5V, 200mA); 2.5 mm connector: tip or ring is connected to pin 33, sleeve to any ground pin on the connector




Spoiler For Axe Code:
Code: [Select]
FnOff
SR(1) //Luminance 100%
SR(17) //Normal Write mode
SR(20) //Disable cursor
SR(12) //Clear Display
0->A //initialize counter
While 1
SR(13) //Carriage Return
SR('A')
SR(' ')
SR('=')
SR(' ')
SR(A/100+'0') //100s
SR(A^100/10+'0') //10s
SR(A^10+'0') //1s
A+1^256->A //increment counter
Pause 100
EndIf getKey(15)
LnReg
Return

Lbl SR //Serial
0->r2 //reset parity
3->port //start bit
For(8)
For(30):End //some delay
If r1.1 // get LSB
r2++
0->port
Else
For(2):En
3->port
End
r1/2->r1  //shift right
End
For(17):End
If r2.1 //parity bit
0->port
Else
3->port
End
For(20):End
0->port //Stop bit
For(25):End
Return
I know it can be optimized and made cleaner, but it does the job ;)

Offline TIfanx1999

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Re: Serial VFD to TI-83+
« Reply #1 on: May 23, 2013, 08:59:25 am »
That's pretty neat! :D

Offline TheNlightenedOne

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Re: Serial VFD to TI-83+
« Reply #2 on: May 23, 2013, 02:46:01 pm »
That's really cool! Nice job!
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Offline DJ Omnimaga

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Re: Serial VFD to TI-83+
« Reply #3 on: June 07, 2013, 11:41:34 pm »
Really nice! I also like how the fonts looks identical to the calc. :)
In case you are wondering where I went, I left Omni back in 2015 to form CodeWalrus due to various reasons explained back then, but I stopped calc dev in 2016 and am now mostly active on the CW Discord server at https://discord.gg/cuZcfcF


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