Thank You HaD!!! I like the combo post :) Please keep it up :)

“there has long been code”

I wouldn’t call 4-6 months as ‘long been’ but the link has been added to my article, thanks.

@Nakka: ah; you’ve never talked to people who haven’t learned about binary. The abstraction of a microcontroller pin to a, well, “pin”, instead of some random masked bit in some weirdly named register is a good thing, IMO. Sure, you can claim that people who can’t understand how “PORTB &= ~(1<<6)" relates to "BIC PORTB,6" or "turn off the green LED" shouldn't be programming at all. But I'd rather not.

Nearly 1 year ago, I wrote an optimized digitalWrite() that compiles to only a single 2-cycle instruction when the inputs are compile-time constants. I’ve been shipping it as part of Teensyduino since November (Teensyduino also has non-const optimizations). The const-case single instruction code has also been sitting in Arduino issue #140, maybe someday to become part of Arduino proper.

@r_d: a good question. It maps the pin number to a port using an indexed lookup to a table stored in flash. And to a bitmask. Check for “not a pin.” More mapping to timer information. If the timer register is ‘real’, it then makes sure that any PWM that that timer might have been driving on that pin is turned off (which involves additional logic.) Map the port to the output register for the port. Read the register, AND or OR the value with the bitmask (possibly complimenting the mask first), and write it back (using indexed addressing in both cases, since the register address is a variable. Which requires expanding the register address to 16 bits and saving some extra registers.) Plus normal function call overhead.

It could be optimized a bit more, but it’s designed to keep the same basic structure across several CPUs, and isn’t really designed to be fast. It doesn’t need to be fast. After all, Arduino is designed with the knowledge that if you really need speed, you can drop into plain C code or even inline assembler. It’s not like some environments where the slow function is your only choice…

Agree with WestfW.
I have a degree in computer science and more than 25 years experience in programming, but no, I can’t handle bit masking error-proof as I can with digitalWrite().
If you are to write a pin, you code should say just that. Any trickery must be delegated to libraries and compilers, IMHO.

@John. Thats what she said

@Matthew Garten He has a bit of annoying speech patterns that guy in the video, irks me how he can’t say arduino but says arduinio, why do people put extra letters in a word? it’s like americans saying wimbleton when pronouncing wimbledon, you can’t figure why they do that.