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Topic: Cheap small capacity SD Cards? (Read 1 time) previous topic - next topic

smeezekitty


Maybe it doesn't comply with the recommended interrogation sequence?  There's a flowchart in the SD specs showing you how to properly differentiate.  It's backward compatible.  If you (as a designer) just initialize and go, instead of probing and verifying behavior, you may end up using the wrong command set.  Just a guess.

So it is not really backwards compatible... If the device is not aware of SDHC than it will fail.
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

SirNickity

Uh... yeah, OK.  Point taken.  I guess I was looking at it the other way around.  An SDHC-compatible reader must... as in, per the spec, absolutely must... know how to tell the difference between SDHC, SD, and MMC cards.  But you're right, there's no guarantee that a new card would work in an old reader that's not aware of fixed block addressing and whatnot.

smeezekitty


Uh... yeah, OK.  Point taken.  I guess I was looking at it the other way around.  An SDHC-compatible reader must... as in, per the spec, absolutely must... know how to tell the difference between SDHC, SD, and MMC cards.  But you're right, there's no guarantee that a new card would work in an old reader that's not aware of fixed block addressing and whatnot.

Thats the problem I have. Lots of old devices.
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

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