Difference between revisions of "How to drive many leds with a few io-pins"
From Just in Time
m (2 revisions: copying content from old site) |
m |
||
| (One intermediate revision by one other user not shown) | |||
| Line 2: | Line 2: | ||
The 12F509 Knight Rider uses this technique to switch 12 leds with only 5 I/O pins (the 6th pin is input only, so 5 is the max for the 12F509). | The 12F509 Knight Rider uses this technique to switch 12 leds with only 5 I/O pins (the 6th pin is input only, so 5 is the max for the 12F509). | ||
| + | |||
| + | In the meantime, we have learned that this technique is called [http://www.google.com/search?q=charlieplexing Charlieplexing]. So we weren't the first.. | ||
Latest revision as of 23:50, 1 April 2012
For any straightforward led matrix you can double the number of leds by using tri-state switching and parallel reversed leds.
The 12F509 Knight Rider uses this technique to switch 12 leds with only 5 I/O pins (the 6th pin is input only, so 5 is the max for the 12F509).
In the meantime, we have learned that this technique is called Charlieplexing. So we weren't the first..