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Topic: What's the best way drive multiple LEDs simultaneously? (Read 1 time) previous topic - next topic

njsss

Hi, I'm new to arduino. I currently have a mega 2560 and about 40 LEDs. I want to drive them one by one and also some (or all) selected LEDs at the same time. From the reference, it seems that I can use port manipulation (DDRX, PORTX). However since all the pins are spread out to multiple ports, will there be a lot delay between pins located in different ports?

CrossRoads

#1
Feb 07, 2012, 07:02 am Last Edit: Feb 07, 2012, 07:04 am by CrossRoads Reason: 1
Not so that you would notice.  16 MHz is pretty darn fast!
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Grumpy_Mike

You can use the normal digitalWrite on all the pins and you will still not see any delay.

John_S

Just beware of the total current limit of the mega. I believe it's 200ma, which would be 5ma per LED to prevent damage.

Grumpy_Mike

Quote
I believe it's 200ma,

Bit of a grey area this. The data sheet says power & ground is limited to 200mA per pin. But the Mega chip has 4 pins so that might make it 800mA. But others disagree.

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