user15994: I have an SD breakout for my Due that isn't properly detecting the SD card. On one card, it cannot detect at all, and the other it says that the SD isn't formatted with FAT, even though it is. Here is my wiring:

simulate this circuit – Schematic created using CircuitLab
So, I broke out my oscilloscope and started probing lines. One in specific I got worried about, is the SCK line and it's bouncing, specifically from the inductance of the jumpers. This is the SCK line from my scope:

My reaction was to put some buffer caps on there, and so I put 2x 300pf capacitors in parallel for a total of 600pf. This is the waveform as measured after I put in the debouncing caps:

This is much more tolerable, and I can accept this level of bouncing for the SCK line, as I doubt that there will be much misfiring. I upload the SD card test sketch that's on the website, here is the output:
Initializing SD card...Wiring is correct and a card is present.

Card type: SD2
Could not find FAT16/FAT32 partition.
Make sure you've formatted the card

What does The Arduino Due have that makes it hard to detect the card?

user30198: Remove the caps please. Perhaps the scope itself creates the overshoot.
The Due is not special. It should work.
Can you tell what kind of SD memory cards and which SD module you use ?
Try the SD Formatter, see the post at the Arduino.cc forum: "Don't Format SD cards with OS utilities!".
Some SD memory cards are not compatible. Perhaps you have more luck with an older 1GB or 2Gb SD memory card.

15994: <p>I have an SD breakout for my Due that isn't properly detecting the SD card. On one card, it cannot detect at all, and the other it says that the SD isn't formatted with FAT, even though it is. Here is my wiring:</p>



<p><img src="https://i.stack.imgur.com/OGFmZ.png" alt="schematic"></p>



<p><sup><a href="/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fOGFmZ.png">simulate this circuit</a> &ndash; Schematic created using <a href="https://www.circuitlab.com/" rel="nofollow">CircuitLab</a></sup></p>

<p>So, I broke out my oscilloscope and started probing lines. One in specific I got worried about, is the SCK line and it's bouncing, specifically from the inductance of the jumpers. This is the SCK line from my scope:</p>

<p><a href="https://i.stack.imgur.com/1hoBv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1hoBv.png" alt="enter image description here"></a></p>

<p>My reaction was to put some buffer caps on there, and so I put 2x 300pf capacitors in parallel for a total of 600pf. This is the waveform as measured after I put in the debouncing caps:</p>

<p><a href="https://i.stack.imgur.com/uFnQl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uFnQl.png" alt="enter image description here"></a></p>

<p>This is much more tolerable, and I can accept this level of bouncing for the SCK line, as I doubt that there will be much misfiring. I upload the <code>SD card test</code> sketch that's on the website, here is the output:</p>

<pre><code>Initializing SD card...Wiring is correct and a card is present.

Card type: SD2
Could not find FAT16/FAT32 partition.
Make sure you've formatted the card
</code></pre>

<p>What does The Arduino Due have that makes it hard to detect the card?</p>
 30198: <p>Remove the caps please. Perhaps the scope itself creates the overshoot.</p>

<p>The Due is not special. It should work.</p>

<p>Can you tell what kind of SD memory cards and which SD module you use ?</p>

<p>Try the SD Formatter, see the post at the Arduino.cc forum: "<a href="https://forum.arduino.cc/index.php?topic=228201.0" rel="nofollow noreferrer">Don't Format SD cards with OS utilities!</a>".<br>
Some SD memory cards are not compatible. Perhaps you have more luck with an older 1GB or 2Gb SD memory card.</p>
