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Dodotronic , 08-28-2017, 02:58 PM

I'm trying to develop a board with multiple SD cards on the same bus.
The solution is to use some switches 74HC4066 each connected to the single SD card so turning on and off the switches I can access the single SD.
The problem is how to route the bus! Is it correct to start from the first switch and continuing the bus up to the last switch? or is it better a star connection?
how can I see the lenght of the bus from the microcontroller to each switch?
There must be some kind of terminator to the bus?
For 4 SD card do I need a clock multiplier such as LMK00804B?
Is there a law to determine the tolerance of the bus based on the bus speed?

Thanks
Ivano

robertferanec , 08-29-2017, 10:54 AM

Maybe you could use switches 1 to X? For example one pin on one side (connected to CPU), X pins on the other side (connected to the slots). Here is an example what I mean, do not use exactly this switch, I picked it randomly from digikey: http://www.intersil.com/content/dam/...4/isl43840.pdf

I am not sure if I would use 1:1 switches.

Dodotronic , 08-30-2017, 01:11 AM

Thanks Robert!
Logic and right answer!