Constant current confusion

[MK14]

It's an Atmega1284, I believe.

Thanks for letting me know.
A quick look at the datasheet, seems to indicate that it will supply 20mA (which is more than enough for your circuit, as shown) per pin (maybe a bit more, it would take longer to find that value), with a limit on the overall current paths.

Disclaimer: The datasheet covers a large number of devices. It is very easy to look up the wrong chip. So please take care, before using the following values.

The 40mA it mentions is the Absolute Maximum, which is best avoided at all costs, as that is the level which may unfortunately break/damage the chip and/or see it misbehave.

Although each I/O port can source more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady
state conditions (non-transient), the following must be observed:

Although each I/O port can sink more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady
state conditions (non-transient), the following must be observed

http://www.atmel.com/Images/Atmel-8272-8-bit-AVR-microcontroller-ATmega164A_PA-324A_PA-644A_PA-1284_P_datasheet.pdf

[tyguy2]

Whoops, 1280

[MK14]

Whoops, 1280

An easy mistake to make.
A super quick look, seems to say my previous post, is about right with the currents, or not very far, from the revised cpu number.

Also, you had no choice but to include the wrong one, initially.
Otherwise you would have got into trouble, for being off-topic, the topic title being 'confusion'.

[tyguy2]

Oh, putting confusion in the title isn't allowed? My bad, I'll remember for next time

[Brumby]

Putting 'confusion' into the title isn't a bad thing ... but since you did, citing the wrong chip number was a good move.  It kept the thread 'on topic'.   

[MK14]

Oh, putting confusion in the title isn't allowed? My bad, I'll remember for next time

Sorry. I was joking, as explained by:

Putting 'confusion' into the title isn't a bad thing ... but since you did, citing the wrong chip number was a good move.  It kept the thread 'on topic'.   

Thanks for explaining it.

The joke was that "Confusion" in the topic title, meant that you HAD to create the mistake on purpose, otherwise you would be off-topic. N.B. I was joking.

Also take care, as previously mentioned, the VERY BRIGHT LEDs can potentially damage your eye sight. Eyes can't handle overly bright light sources too well. Unlike a faulty component, where you can just buy a new one. Eyes are not so easily replaced.

[David Hess]

Also take care, as previously mentioned, the VERY BRIGHT LEDs can potentially damage your eye sight. Eyes can't handle overly bright light sources too well. Unlike a faulty component, where you can just buy a new one. Eyes are not so easily replaced.

"Do not look into bright LED with remaining eye" just does not have the right ring to it.

[tyguy2]

"Eye" see what you did there.

[MK14]

Related, but different example (lasers rather than LEDs). Warning: Unpleasant details!
http://www.americanews.com/story/health/2015/11/06/teen-permanently-lose-75-percent-vision-due-one-little-toy