Scrambled display

[gibbs]

Hello,

Ive have attempted to make the digitshield on a breadboard to do some testing before ordering one. I have followed the schematic with the only difference being I am not using the same display (I have one 4 digit display) and I am not using any decimal points.

I have it working partially but I am getting some strange behaviour.

Here us my sketch

#include 



void setup() {

DigitShield.begin();

}



void loop() {



int n = 8888;



DigitShield.setPrecision(0);

DigitShield.setValue(n);





}

and here are my results (- = digit not on)

Variable N Output
8888 8888
1 -111
2 -222
3 to 9 exhibit the same behaviour as 1 and 2
10 1000
11 1111
12 12 backwards 6 backwards 6
13 1333
14 1444
15 1599
16 1688
17 1777
18 1888
19 1999
20 2088
21 21 backwards 6 backwards 6
22 2222
23 23 backwards 6 backwards 6
24 2488
25 2588
100 0000
1000 0000

Any help would be great

14 1444

[Michael]

Are you changing the value of n in your sketch somewhere? I don’t see any change…

I guess all I can ask is “are you sure you have it wired correctly?” because if you’re using different display hardware, it will have a different pinout… Is it common anode display?

[gibbs]

Hi Michael,

Sorry I was changing N manually and then re-uploading the sketch. I am using a common anode display with 12 pins (7 segments, colon and 4 digits) and have got each digit displaying correctly in at least one case so I think it might be a software rather than hardware issue (I have double checked the wiring but I will have another look!)
I will have a poke about the library and see if its something to do with precision or the lack of decimal points.
One think that is really confusing me is the Backwards 6 (lighting up all segments except the top-left vertical) is this used anywhere as an error code?

Thanks for you help

Dave

[Michael]

The library is designed to work with the Digit Shield hardware, so if your circuit doesn’t work, then it’s because your circuit/hardware is different from the Digit Shield somehow. How can it be a “software problem”? Obviously the software is working with the Digit Shield — it’s been on the market for almost a year. I’m not sure what you are trying to accomplish with your testing — are you unsure whether the library will work with the Digit Shield? It does!

It’s not possible to display a backwards 6 with a properly connected 74LS247 chip, so I have no idea how that is being displayed. Have you consulted the datasheet?
http://www.datasheetcatalog.org/datasheets/480/337938_DS.pdf

[gibbs]

Hi Michael,

I apologise, I wasnt suggesting your library was at fault merely that perhaps my hardware modifications were incompatible with your library due to the lack of decimal points.

Ive had a look at the data sheet and I agree a backwards 6 should be impossible so I will continue looking for a mistake in my wiring.

thanks for you help

[Rosette Bravo]

I downloaded the DigitShield zip file and installed the library in my main Arduino libraries folder. When I open the “SetDirectExample” and compile, I receive the following error:

[Michael]

what error? I don’t see anything in your post.

[Author]

Posts