It appears that nobody really knows much about using SD cards in their "full-speed" mode. That's why the discussion has wandered. I freely admit, I'm the one who introduced the notion of sharing difficult-to-find information. Apparently there are some who'd oppose such sharing. It doesn't mater much to me ... I generally have little trouble getting information I need, though I dislike having to pay for it.

As far as the copyright discussion ... Well, nobody seems to know much about that either. There are a lot of assumptions that have been aired time and again, but ... having discussed the matter with patent attorneys, etc, I'm persuaded that it's not as clear-cut as some would have us believe.

If you publish a book, that gives you certain rights regarding the content. After all, a person has to have possession of the book in order to use it. If you publish a billboard ... well, the picture may belong to you in perpetuity, but the written content? There is, after all, such a thing as the doctrine of "fair use" to be considered.

People who publish software would like us to believe certain things about their rights. People who pay for and use that product would like us to believe certain things about their rights, too.

If I own a book, I can lend it to my friend or neighbor. A question arises, however, if that's an electronic book, or, for that matter, a specification, of which I now have a copy. Can I make that available for my friends and neighbors to use, in the manner the original publisher intended? I haven't seen any cited statutes. Statutes generally restrict us by telling us we can't do. They don't tell us what we can do.

My interest in using SD in 4-bit mode is because of performance. Most MCU applications don't demand much performance. It's no surprise that few, if any, 805x users have bothered with SD cards beyond the SPI mode.

RE