Electrical – AXI SPI of MicroBlaze connected to SD card

fpgamicroblazespi

I would like to connect SPI IP core of microblaze on custom board but I have some problem.
I need 100-400 KHZ clock but the system clk is 100MHz and SPI Clock is 6.25 MHz.
Is it necessary to reduce clk frequency for initialization?

I just send CMD0 to reset,I would like to check the write and read buffer to see tranfering of command is correct,but I couldn't get a correct result.

IS anybody can help me ?

Best Answer

Is it necessary to reduce clk frequency for initialization?

Yes. SD cards come up in open drain mode - you also need a pullup. This resistor limits the answer speed of the card until it switches into SPI mode fully.

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