MicroSD card breakout board (PID: 254)

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johnbarr
 
Posts: 8
Joined: Wed Sep 25, 2013 2:25 am

Re: MicroSD card breakout board (PID: 254)

Post by johnbarr »

Rick: CD works as you describe - WHEN IT WORKS.
There is always continuity between the metal case and GND whether or not it works.
Inserted and removed card multiple times:

With a card inserted, CD is always disconnected from ground
With the card removed and no connection showing (reader failure), pressing down on one of the fingers DOES connect it.

The first few times I removed the card, CD worked (was grounded).
On subsequent tries, CD worked ONLY SOME OF THE TIME.

(This is, of course, consistent with what we see in our software.)

I find it very interesting that it should fail in spite of the two-finger redundancy!

WHAT IS THE NEXT STEP? Replacing the cards? Voiding the warranty by bending the fingers? (This might be the thing to do to the card reader that is soldered in place.)

johnbarr
 
Posts: 8
Joined: Wed Sep 25, 2013 2:25 am

Re: MicroSD card breakout board (PID: 254)

Post by johnbarr »

There is no point in checking the jumpers (actually short wires 1.25" long) because when it fails, it is the card reader, connected or disconnected, that fails. It is the contacts on the card not contacting the case when the card is removed.

PREVIOUS POST (LOST?) REPEATED:
Rick: CD works as you describe - WHEN IT WORKS.
There is always continuity between the metal case and GND whether or not it works.
Inserted and removed card multiple times:

With a card inserted, CD is always disconnected from ground
With the card removed and no connection showing (reader failure), pressing down on one of the fingers DOES connect it.

The first few times I removed the card, CD worked (was grounded).
On subsequent tries, CD worked ONLY SOME OF THE TIME.

(This is, of course, consistent with what we see in our software.)

I find it very interesting that it should fail in spite of the two-finger redundancy!

WHAT IS THE NEXT STEP? Replacing the cards? Voiding the warranty by bending the fingers? (This might be the thing to do to the card reader that is soldered in place.)

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: MicroSD card breakout board (PID: 254)

Post by adafruit_support_rick »

We will replace the ones with the bad card detect fingers. Please email [email protected] with a link to this thread to arrange a replacement.
johnbarr wrote:I find it very interesting that it should fail in spite of the two-finger redundancy!
Me, too. That is very strange. Must be from a funky batch. Maybe some crud got on the contacts?

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Re: MicroSD card breakout board (PID: 254)

Post by adafruit »

We do test for CD in production and I tested a sampling of them by hand just now. All worked correctly, CD is shorted to ground when a card is not inserted and is 'floating' when a card is in place. A light pullup resistor is required.

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kapheine
 
Posts: 1
Joined: Mon Sep 03, 2018 7:10 pm

Re: MicroSD card breakout board (PID: 254)

Post by kapheine »

I'm curious if others have had this problem as well. I never see continuity between GND and CD. I've tried pushing, poking, and prodding the fingers but GND and CD never connect. I do see continuity between GND and the casing. Could it really be a defect or am I doing something wrong?

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