Comments on: Two LEDs on 1 AVR line http://www.muzique.com/news/two-leds-on-1-avr-line/ Stompboxes, Schematics, Guitars and Electronics Thu, 09 Feb 2012 00:01:56 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: admin http://www.muzique.com/news/two-leds-on-1-avr-line/comment-page-1/#comment-1283 admin Sat, 07 Aug 2010 13:17:34 +0000 http://www.muzique.com/news/?p=664#comment-1283 Skot, I tried the single resistor version first and it did not work as well as having separate resistors... if fact, if I'm not mistaken, it would not work at all. I think if you tri-state the micro pin, both LEDs should be lit in my version. I've been planning on breadboarding this to check it out. -Jack Skot, I tried the single resistor version first and it did not work as well as having separate resistors… if fact, if I’m not mistaken, it would not work at all.

I think if you tri-state the micro pin, both LEDs should be lit in my version. I’ve been planning on breadboarding this to check it out.

-Jack

]]> By: Skot Wiedmann http://www.muzique.com/news/two-leds-on-1-avr-line/comment-page-1/#comment-1281 Skot Wiedmann Thu, 05 Aug 2010 19:01:41 +0000 http://www.muzique.com/news/?p=664#comment-1281 Save one resistor by connecting it between the pin and the LED instead. Or raise the resistor values enough that a tristate pin can let them both float off. Then you can use a fairly fast square wave to turn them both on. 4 states from one output pin! Save one resistor by connecting it between the pin and the LED instead. Or raise the resistor values enough that a tristate pin can let them both float off. Then you can use a fairly fast square wave to turn them both on. 4 states from one output pin!

]]> By: admin http://www.muzique.com/news/two-leds-on-1-avr-line/comment-page-1/#comment-1077 admin Thu, 27 May 2010 23:23:13 +0000 http://www.muzique.com/news/?p=664#comment-1077 This is better than charlieplexing for small numbers of LEDs... each AVR or PIC output pin with this method can drive 2 LEDs. If you are using 3 output pins, then 6 LEDs can be controlled, which is the same as with charlieplexing. However, 2 output pins in charlieplexing can only control 2 LEDs, but 4 can be used with this method, and nothing can be done with 1 charlieplexed pin and 2 are controlled here. For more than 6 indicators, charlieplexing is the way to go but for 6 or less, this is a better idea, especially since it is so easy to write code for it. Just toggle the right pin to turn on a selected LED - no matrix to worry about and no tri-state! This is better than charlieplexing for small numbers of LEDs… each AVR or PIC output pin with this method can drive 2 LEDs. If you are using 3 output pins, then 6 LEDs can be controlled, which is the same as with charlieplexing. However, 2 output pins in charlieplexing can only control 2 LEDs, but 4 can be used with this method, and nothing can be done with 1 charlieplexed pin and 2 are controlled here.

For more than 6 indicators, charlieplexing is the way to go but for 6 or less, this is a better idea, especially since it is so easy to write code for it. Just toggle the right pin to turn on a selected LED – no matrix to worry about and no tri-state!

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