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It seems all SD card specifications mentioned two frequencies (fOD and fPP) as used in identification and data transfer mode respectively. What do the subscripts (OD and PP) mean?

Peter Mortensen
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bruin
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1 Answers1

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They mean Open Drain and Push Pull.

Identification is done slowly in OD mode so all devices can be enumerated without one driving the bus into other direction than others.

Data transfers can then happen with one device at a time so it can be done faster in PP mode.

Justme
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