Any Circuit diagram for Seven Segment display that can

[Guest]

Arthur,No, I dont think they are the same thing at all. The MAX has a serial interface and can drive 64 individual LEDs, and while I dont know what a 7448 is, if its a 74LS series IC of some sort, then I'm pretty sure they are not the same thing.Dave

[Guest]

Hi Dave, Okay... I am duly noted, They are not same... Apparently, all of the information I need are stacked up in my mind, except for one thing...Do you know if I could find any circuit diagram of Max7219 along with Seven Segment digit display? I just want to take a look at it and prepare everything because I have already order MAX7219 from digitkey.

[Guest MikePowell]

Arthur,You can find a lot of information about the MAX7219 on the Maxim/Dallas web site www.maxim-ic.com/quick_view2.cfm?qv_pk=1339 The 7447 and similar chips are very basic seven segment decoder/drivers. They take a 4 bit BCD code as input and provide the drive current for the individual LED segments of a single 7-segment display. The MAX7219 or ICM7219 and their varients are significantly more complex and capable. You might think of them as incorporating the 7447 circuitry along with memory to hold the digits they are to display, an interface better suited to micro processors and the scan circuitry to allow driving 8 7-segment displays.Mikewww.mikesflightdeck.comInfo for simpit builders

[LawnDart 19]

...that actually sounds like the ol' 7447 - 7490 Up/Dn Counters with Latch.Living a few blocks away from the local Radio Shack as a child did have it's advantages, but was a constant drain on my allowance!

[Guest MikePowell]

That's it. This functionality was developed back in the days of nMOS chips by Intersil (probably by others as well) as a replacement for the TTL approach. It's been improved as silicon processes have developed, but the functionality is pretty much the same. Mikewww.mikesflightdeck.com

[Guest]

Only thing I hear is, 7447 has a constant changing on the BCD based on everytime I toggle the switches. but, would not make a compatible with EPIC-- meaning, for instance if running FSXX it will not send any such kind of data information regarding to COMM, NAV or such other kind of freqs along with IC7447 (would not appear on any seg). Unless, I would need to add more chips that would have this kind of function (storing information/memory) . So, MAX7219 has everything I need, and it would be the best answer...

[Guest MikePowell]

Arthur,You are correct. A 74LS47 would not by itself do what you need. The MAX7219 has significantly more functionality. You could build that same capability by using a number of 74LS-series chips, or by using a microcontroller like a PIC16F628 with a few support chips, but it is likely more simple simply to use the 7219.Mikewww.mikesflightdeck.com

[Guest]

Dave you made me drop from the bed!I had the max 7219 sitting on my desk for too long...I never had the courage to start assembling some code for a pic...Now you tell me you can attach one or more to that stupid thing called parallel port?I think i'll make you a monument!Could you drop that beta thingie to me too?I'm not much in oop and vb, i only now ansi c...But i could anyway use a look if you don't mind.Since max7221 have Cable/Select pins, have you thought about using many of them on the same data line?

[Guest]

Arthur,whats your email address? And yes, I have them cascaded on single pin, max of 8 per pin on the parallel port. So you can have 64 hanging off a single parallel port......Dave

[Guest]

I would be interested too. ThanksMy e-mail: roger.wielgus@noos.fr

[Guest]

erupter@tiscali.itThank you very much!

[Guest]

>Arthur, >>whats your email address? And yes, I have them cascaded on >single pin, max of 8 per pin on the parallel port. So you >can have 64 hanging off a single parallel port...... How is the count?64 what?Single LEDs?If single LEDs you alread have 64, with one single max.Are you talking about 64 max on the parallel??????Thus makeing 4096 single LEDs or 512 7segs????????????

[Guest]

Right, 512 7-seg LEDs per parallel port (or, as you point out 4096 single LEDs). Lots of room for all the bells-and-whistles you could want!! And cheap too!! And building the circuit is trivially easy...Dave

[Guest]

FolksI'll upload the code tonight to Avsim's file library, plus a small demo program in VB so you can see how to use the classes. Stay tuned, and please provide feedback.Dave

[Guest]

Hi Dave, Sorry took too long to reply back at you.. I just got home from out town for Thanksgiving weekend. Anyway you can send it to ProjectB767@aol.com . I am still looking forward for the order of MAX7219 from digikey to arrive. You can send in that code so I could get idea. >I'll upload the code tonight to Avsim's file library, plus a small >demo program in VB so you can see how to use the classes. Stay >tuned, and please provide feedback.Sound good! I will take look at it...