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Canberra Australia
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I have been frequenting this fine forum for over a year now and recently I put together this information on different methods of driving 7 Seg displays and would appreciate any suggestions or criticisms  from you, my teachers. Go easy on me I’m the sensitive type  smiley-roll
 just kidding I can take it Pedro.
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I suggest you find out how to do code tags on your blog. Having the code in "normal" font makes it hard to read.
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Canberra Australia
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Thanks for that Nick.

Yes not having any experience with what I assume is HTML I will look into how to make the code more legible. Thank you for your suggestion I appreciate it
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Grand Blanc, MI, USA
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CODE is a mass noun and should not be used in the plural or with an indefinite article.
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Or even consider putting the code elsewhere, e.g. GitHub, Google Code, a link to the same site, etc. If there are particular features in the code to be discussed, then posting snippets (in the manner Nick suggest) will keep the overall post shorter, and focus on the discussion.
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MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

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Since you're using wordpress have a look at,

http://www.viper007bond.com/wordpress-plugins/syntaxhighlighter/
and
http://elabz.com/arduino-syntaxhighlighter/


I used these when I was messing about with wordpress here http://www.74hc.co.uk/lcd-and-button-sharing-io/
Really need to start adding articles on a regular basis, but theres always other things to do!
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Canberra Australia
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Thanks Jack,

but I was hoping to have all the code available on the blog as if there is only a snippet there, what else is to look at other than some amateurish circuit diagrams. Having the full code available,
  just like beige has on his blog
is exactly the look I am after. Obviously I really don’t expect there to be a traffic jam on my site   smiley-lol  but hey a guy has to start somewhere and to me it must be aesthetically pleasing.

Beige,

thanks for the two links and coincidentally I did find both of those this afternoon but from what I can see, am I right in assuming that I have to have a paid up Wordpress.org account to use plugins. Would you be able to give me any advice as to how I can post my code looking as good as yours does on your site. If you experienced IT type Arduino guys thought that I was sketchy on Arduino coding, when it comes to HTML and websites I am a virtual snowy white virgin. Thank to you all for your suggestions they are appreciated

Pedro.

« Last Edit: October 10, 2013, 07:55:13 am by Pedro147 » Logged


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That's cool, too.

... I was sketchy on Arduino coding ...

Pun intended?  smiley-grin
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You guys make all this seem so eeeeasy. I am envious  smiley-cool
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Ah, I've only ever used wordpress on my own web host so not run into that.

Have a look at the pre tag, it's not as fancy but it'll make the code easier to read http://www.w3schools.com/tags/tag_pre.asp

My web design knowledge peaked with HTML4 when people still used tables for layout, these days it's all CSS with a bit of HTML to glue it together.
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Thanks Nick,

I hope your info is good for my mojo  smiley-cool
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What voltage / current draw are you basing your resistor calculations on?

The typical '595 can supply a maximum of 70mA, which at 20mA per segment is three (and a half!) simultaneously. To have all seven segments lit at the same time you don't want to be exceeding 10mA per segment...
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A good point regarding the possible / highly likely excessive current draw in the first three examples that are not multiplexed. As pointed out by CR in an earlier different question I would be wise to change the shift register circuits to use common anode 7 Seg with a  TPIC6B595 SR. As for the direct drive and DPM circuits I will have to consider all the different maximum ratings for –
1.   The whole board
2.   The different port groups
3.   And individual pins
as outlined in Nicks information at -  http://www.gammon.com.au/forum/?id=11473
I did do some measurements previously and from the measurements shown in images Current draw 1 and 2 am I right in assuming that I am not exceeding any of the current rating limitations of the different components within my circuits?
As for my circuit examples 4 and five, I believe that the code is multiplexing the displays and therefore should present no problem in regard to excessive current draw but I should actually check it rather than assume  smiley-grin
But as always I defer to the recommendations of you guys in the know, as they say and eagerly await your thoughts on what I have outlined here.

Thanks Pedro.


* Current draw 1.png (42.73 KB, 1189x646 - viewed 34 times.)

* Current draw 2.png (19.34 KB, 664x617 - viewed 31 times.)
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Quote
As for my circuit examples 4 and five, I believe that the code is multiplexing the displays and therefore should present no problem in regard to excessive current draw but I should actually check it rather than assume

That isn't a multiplexing chip and as far as I can see you are not multiplexing in code.

The MAX7219 is a multiplexer.

To test, show an 8 and measure the current.
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To test, show an 8 and measure the current.

If I use the code from circuit examples 4 or 5, which are inherently the same except that in one the counter is incremented and decremented by a pair of pushbuttons whereas the other by a pot position, this is what I measure. With the multimeter set at 20m, presumably 20 mA, and the test leads in series with the 5 volt header from the Arduino and the 5 volt rail of the breadboard the reading is 14.35 which I again assume is the total current that the circuit is drawing. When I place the multimeter in series with one segment of the 7 segment display again still set on the 20m range I get a reading of 0.37. This is all with the code set to display only the eight numeral. Does it seem that this code is multiplexing and do I have a problem with excessive current draw within this circuit? Also is my procedure for checking current draw sound.

Thanks Pedro
« Last Edit: October 10, 2013, 06:40:54 pm by Nick Gammon » Logged


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I honestly find all that left-justified code almost impossible to read.

Also, this part doesn't even compile:

Code:
if(potReading > 8)
potReading –;
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