16 Mar
2006
16 Mar
'06
6:34 a.m.
Chris M wrote:
weve all seen the use of (typically) compact flash
cards as mass storage in classic stuph. Are SD cards
as adaptable for this purpose?
no, sorry. while CF cards can be run in "true ide mode" which makes
them look essentially like IDE hard drives, SD & MMM cards use an
entirely different interface.
I could on and on but suffice to say:
- mmc cards are thinner. sd won't go in an mmc slot. sd cards are
thicker. sd slots can take mmc cards.
- both mmc & sd cards can use a simple 4 wire spi interface to allow
random block access (i.e. random access to blocks of data)
- the interface is very simple. I've done DOS/FAT file system access to
an MMC using PIC. I'm doing it as we speak with an Atmel SAM7S (in C).
I think there are a number of SD card interface sites on the web, as well
as specs for the interface.
I'm working on a "vintage computer to modern media" interface right now
and I've chosen CF & IDE - mostly becuase there are lots of pc based
interface to these, makeing interchanging the media simple.
-brad