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[MosaicDave]

So I've come upon the #DEFINE for TWI_CHECKED_ENABLED in config.h (enabled by default in the current OSV3 release code) but can't find any clear commentary or discussion about this parameter. I can see where it's being used in twi.h / twi.c, so it's clear enough basically what it's doing. But I find I'm having a few questions; if someone can clear this up for me a bit, that would be great:

-- Is this I2C checksum protocol, an implementation of something that is part of any standard? Or is this really just an OpenServo specific thing?

-- With TWI_CHECKED_ENABLED enabled, as it is in the default released code, are there times when you must send requests with a checksum? In other words, are there conditions under which ordinary, common I2C read/write/command requests will be rejected by the servo, because I didn't create a checksum?

-- Additionally, if anyone can provide (or point me to) a brief, high-level explanation as to how this checking is supposed to work in practice, that would be great. I can follow through the code and see what's going on, but the exact flow of things under different conditions and cases is a little hard to follow.

Thanks much--

--Dave
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[ginge]

Hi Dave,

[quote]- Is this I2C checksum protocol, an implementation of something that is part of any standard? Or is this really just an OpenServo specific thing?[quote]

I2C makes no provision for checksums, in fact I2C makes no real provisions about anything! To this end it is OpenServo specific

[MosaicDave]

Great, Barry - thanks much.
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http://www.mosaicengineering.com/