You can still use a pair of I/O in parallel to drive up to 50mA. It's been widely used in the past. I'm not a fan of it... but sure it may work. You just need to play with the WHOLE TRIS register value.
|
You can still use a pair of I/O in parallel to drive up to 50mA. It's been widely used in the past. I'm not a fan of it... but sure it may work. You just need to play with the WHOLE TRIS register value.
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
|
There are LEDs and then there are LEDs. They can vary widely in their brightness output. For example, these are 2 green LEDs in a 5mm, T-1 3/4, thru hole package. Both are rated at a test current of 20mA.
http://search.digikey.com/scripts/Dk...me=511-1191-ND
This one has a rated output of 100mcd. This is typical of commonly available LEDs, 50 -300mcd.
http://search.digikey.com/scripts/Dk...FPG1-15Q-A3-ND
And this one has a rated output of 34,000mcd.
The output of the 2nd. one is 340 times that of the 1st. And it is not even a matter of price - both of them are about the same. So if the LED is bright enough for you at 20-25mA, just go for it. If not, get a brighter one. No need to mess with paralleling outputs, using BJT's or MOSFETS etc.
|
Almost...Originally Posted by rmteo
The 1st one, at 10 degrees off center still looks about 70% of it's total.
The 2nd one, at 10 degrees off center is only about 30% of total.
So while the one may be brighter, it's only brighter in the middle, it's got a bit more focus...if that makes any sense...
|
Sure does. My point is that if you are using an LED as an indicator, 20-25mA is plenty to get a sufficiently bright display with the right LED. A high efficiency LED at just 1mA can be almost blindingly bright.
|
Absolutely TRUE!
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
|
Agreed. It is just an indicator.Sure does. My point is that if you are using an LED as an indicator, 20-25mA is plenty to get a sufficiently bright display with the right LED. A high efficiency LED at just 1mA can be almost blindingly bright.
|
34000mcd... awesome! I didn't even think such exist
What if I put one on my car ...
|
34000mcd (http://en.wikipedia.org/wiki/Candela) sounds really bright and really impressive, and they are fairly bright when viewed straight on...but it's not all that.34000mcd... awesome! I didn't even think such exist
What if I put one on my car ...
These are what I used in my toobz...
http://www.philipslumileds.com/pdfs/DS05.pdf
70mA drive current with a 1/2 power viewing angle of 90 degrees.
They aren't the Luxeon super bright, multi-watt, power LEDs, but they do well.
|
Unfortunately I don't have enough pins. One pin only can be dedicated to a led. I will use the led at lower voltage as many suggested in this thread.
Members who have read this thread : 0You do not have permission to view the list of names.
Posting Permissions
Bookmarks