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dhiltonp / hexbright

The easiest way to start programming your hexbright.
BSD 2-Clause "Simplified" License
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Write custom versions of arduino functions? #13

Open dhiltonp opened 11 years ago

dhiltonp commented 11 years ago

Arduino's pinMode, (digital/analog)(Read/Write) take up 850 bytes all together.

Writing non-generalized versions for our library could reduce our flash footprint. Investigate costs/benefits.

dhiltonp commented 11 years ago

Maybe we can pull in this patch:

http://code.google.com/p/arduino/issues/detail?id=140

dhiltonp commented 11 years ago

I've pulled in this library, which is the implementation discussed here.

pinMode -> pinModeFast digitalWrite -> digitalWriteFast analogWrite -> analogWriteFast

This saves around 250 bytes, and reduces execution time.

dhiltonp commented 11 years ago

arduino-lite seems to be poorly maintained, but it should have a macro for analogWrite, which could be useful. No such optimization seems to exist for analogRead.

dhiltonp commented 11 years ago

http://maxembedded.com/2011/06/20/the-adc-of-the-avr/

This link demonstrates how to convert analog to digital on the avr. We currently use similar code in read_avr_voltage.

dhiltonp commented 11 years ago

adc reading implemented in read_adc.

joshgoebel commented 10 years ago

If we have those functions now isn't this completed?

dhiltonp commented 10 years ago

I've not verified that all arduino functions are replaced (doable by compiling the library directly in avr-gcc)

joshgoebel commented 10 years ago

Well, it's only a replacement if all the pins and values written are constants as determined by the compiler and therefor the dynamic code paths can be optimized out. So I assume you mean confirm that that is the case with the default compile of hexbright.h?

How were you planning to confirm that? Dissassembly?

dhiltonp commented 10 years ago

Part of the desire was to make this library usable outside of the arduino environment, compiling via avr-gcc while including/linking no arduino code.

At this point, I believe most of the inefficiencies of the arduino libraries have been resolved (interesting catch on the linked ram, by the way), so this is much less of a priority than before.