> The other issue that comes into play is rounding itself. > For example, there are 3 ways to round cycles. > - up (delay is always *at least* as long as requested) > - down (delay is closest as possible without going over but can be worst > case > nearly 1 cycle shorter than requested) > - closest (picks closest cycle which could round up or down) >
In all of the places that I've used delays, I'd always want them to error on the side of being a cycle to long, than any amount of to short. Just for completeness, here is a summary of rounding methods: http://www.pldesignline.com/showArticle.jhtml?articleID=189600747 * Round-Toward-Nearest * Round-Half-Up (Arithmetic Rounding) * Round-Half-Down * Round-Half-Even (Banker's Rounding) * Round-Half-Odd * Round-Ceiling (Positive Infinity) * Round-Floor (Negative Infinity) * Round-Toward-Zero * Round-Away From-Zero * Round-Up * Round-Down * Truncation (Chopping) * Round-Alternate * Round-Random (Stochastic Rounding) * Sign-Magnitude Binary Values * Rounding Signed Binary Values -- http://blog.softwaresafety.net/ http://www.designer-iii.com/ http://www.wearablesmartsensors.com/ _______________________________________________ AVR-libc-dev mailing list AVR-libc-dev@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-libc-dev
