SDIO and 50MHz ?

[antonius]

Posted on April 12, 2014 at 08:14

Guys,

Why can't I use 50MHz for SDIO ? GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; it worked only with 10MHz GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;

1.
/*!< Configure PC.08, PC.09, PC.10, PC.11, PC.12 pin: D0, D1, D2, D3, CLK pin */
2.
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12;
3.
//GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
4.
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
5.
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
6.
GPIO_Init(GPIOC, &GPIO_InitStructure);

Any ideas ? thanks

[Tesla DeLorean]

Posted on April 12, 2014 at 13:57

How do you have this wired up? And how long are the wires?

I connected my socket with 33K pull-ups, and wires around 25mm (2.5 cm, 1'') long.

What do the signals look like on the scope? Do you observe any cross-talk, ringing, etc? What's the clock rate being used (on the bus, not the pin driver slew rate setting)?

[antonius]

Posted on April 12, 2014 at 14:59

my wire is 20cm and 10K pull up?...