| ??? 09/27/09 00:23 Read: times |
#169179 - specifically with 805x and NO SD-specific hardware on-chip Responding to: ???'s previous message |
Andy Neil said:
I'm aware of some non-8051 implementations, using specific on-chip SDIO hardware: They are for use with FAT file system implementations, but the SD "driver" part is pretty well de-coupled from the FAT stuff.
ie, as far as the SD code is concerned, that fact that it's being used by a FAT implementation is irrelevant. Not always. The focus on FAT, or whatever file system, often interferes with clean, clear, and efficient implementation of the SD protocol. Unfortunately, few implementations are cleanly layered, as they should be. If that's of any use to you, I can look-out the specific details...
I'm more concerned with whether it's actually been done without a file system than with the low-level details. I've had at least a dozen people tell me that it's just too fast a protocol, too involved, to be done on 805x's, as they're too slow, yet the big 32-bitters aren't really any faster, since they most often don't have 4-bit-data-handling instructions, and therefore have to waste a lot of time processing the bytes and nybbles. There are some low-level details that interest me, of course. RE |
