Fast analog

[alex-ong]

Short PR to allow Fast Analog reads on non Teensies.
I've also moved the .ino file into a folder called fsr, so that relative imports work cleanly.

[alex-ong]

Solves #26 and #21

[teejusb]

I think the stuff in this file is small enough that it can just be in the main ino for now (and also move the fsr.ino back to the original location). I do plan on splitting up the file a bit later down the road.

[alex-ong]

Ahh ok, i figured that a lot of the features needed to be double wrapped (e.g. EEpromEX for ATmega vs teensy is different) and a bunch of those C++ classes could move. But if you want to do that on your own i'll move everything back.

[teejusb]

This if statement is for boards that ARE teensy. I would remove this altogether in favor of the changes suggested above.

[alex-ong]

Yup, sorry i didnt do it right ;(

[teejusb]

Remove this library and do the following:

At the top have this:

#if defined(_SFR_BYTE) && defined(_BV) && defined(ADCSRA)
  #define CLEAR_BIT(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
  #define SET_BIT(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

And then in setup do

#if defined(CLEAR_BIT) && defined(SET_BIT)
  // Set the ADC prescaler to 16 for boards that support it,
  // which is a good balance between speed and accuracy.
  // More information can be found here: http://www.gammon.com.au/adc
  SET_BIT(ADCSRA, ADPS2);
  CLEAR_BIT(ADCSRA, ADPS1);
  CLEAR_BIT(ADCSRA, ADPS0);
#endif

[alex-ong]

Thoughts on wrapping that second part in a function such as SetFastAnalog()?

[alex-ong]

I made all the changes. If you want i can squash them all into one (or you can do that :) )

:)

[alex-ong]

Hi just nudging this since the sooner its merged the better :)

[teejusb]

AH SORRY I didn't really see the update. I think this looks good! I haven't personally tested this for Teensy (and it seems like it's possible for it to run for Teensy with the current control flow). Do you know if this works for Teensys and the behavior one might see?

[alex-ong]

Unfortunately I am a poor Australian who can only afford a bucket of pro micros, so I have not tested with teensy.
Teensy 2.0 uses 32U4, so it should automatically work.
For teensy 3.0+, they use MK20DX256 32 bit ARM Cortex-M4 72 MHz, so the code should slide by without affecting it. They might already read analog quickly; i don't know since i've never dabbled in teensy land

[teejusb]

Yeah I think it should be okay too. I'll merge this and if someone complains that something has been broken I can always adjust things easily. Thanks for the PR!

[teejusb]

(Also what's your discord so I can credit you?)