As a designer, how do you make choices?

I have been using  NeoPixel Mini 3535 RGB LEDs as my go to indicator on my boards.  At < $0.20 in quantity of 100, it is cheap enough, and the RGB capability gives me a bit more flexibility. 

Cool method. How many lines of code does it take to make it indicate something?

Coding in 'C' it takes about 18 lines of code to send the serial string to the NeoPixel, which I do with a bit-banged IO port (pin).  There is an additional overhead to build the string, which is 3 lines of code for each color intensity change.  The programming string is 24 bits, for the 3 LED intensities, GRB ordering, 8 bits each. The timing is pretty critical, so the code must run with interrupts off (or at least make sure that the code can run without being interrupted).  A 'zero' is .2 to .4 us high time, while a 'one' is .58 to 1.0 us.

Doing this with bit-banged IO, there are some changes to the code that need to be made to account for the microprocessor clock speed.  As the clock speed increases, you need to add additional 'NOP' commands to keep the clocking rates correct.

Sure, it is easier to just toggle a pin, but using smaller microprocessors, pin are at a premium.  Being able to 'blink' in different colors is a nice added feature.  Also, the NeoPixels are daisy chainable, so multiple LEDs can be driven off the same pin.

I have a client that wanted 256 level programmable RGB LEDs for his project and theses are cheaper that other approaches.

Coding in 'C' it takes about 18 lines of code to send the serial string to the NeoPixel, which I do with a bit-banged IO port (pin).  There is an additional overhead to build the string, which is 3 lines of code for each color intensity change.  The programming string is 24 bits, for the 3 LED intensities, GRB ordering, 8 bits each. The timing is pretty critical, so the code must run with interrupts off (or at least make sure that the code can run without being interrupted).  A 'zero' is .2 to .4 us high time, while a 'one' is .58 to 1.0 us.

Doing this with bit-banged IO, there are some changes to the code that need to be made to account for the microprocessor clock speed.  As the clock speed increases, you need to add additional 'NOP' commands to keep the clocking rates correct.

Sure, it is easier to just toggle a pin, but using smaller microprocessors, pin are at a premium.  Being able to 'blink' in different colors is a nice added feature.  Also, the NeoPixels are daisy chainable, so multiple LEDs can be driven off the same pin.

I have a client that wanted 256 level programmable RGB LEDs for his project and theses are cheaper that other approaches.

And of course after you have done the code once, you can reuse it on any project without re-inventing it ...

That is so true.  I have used this same code (with timing modification) is several products/projects.  I really try to re-use code wherever possible.