SD card problems

edge87

I bought a SD card board from sparkfun.com and soldered it up as follows.

'                      10k resisters from 3.3v rail 
'   p0 ───────────┻─┼─┼─┼─┼────────── do
'   p1 ─────────────┻─┼─┼─┼────────── clk
'   p2 ───────────────┻─┼─┼────────── di
'   p3 ─────────────────┻─┼────────── cs 
'                          └────────── irq
                  power ground_______ gnd
                     3.3v rail_________ vcc
 

When i have no card inserted into the socket. My continuity test fails from VCC to anything else. However when a card is inserted there is VCC present on all pins. I'm not sure if i have a bad reader or what.

When i attach power to the bread board in this configuration the board shuts off. It browns out with a 9v battery. Hooking up my converted computer power supply 3.3v to the rails it senses something wrong and shuts down (again with the card in ) am i doing something very wrong with this setup?

I have attached a photo of my setup to help resolve this.

soshimo

I think you are missing a ground jumper. Look at the picture just above and to the right of the green LED. Should there be a wire jumpering ground between the breadboard blocks? I don't know if that's your problem but that is suspect. It looks like ground is left floating on your prop chip.

Hmm, I also noticed you are missing a current limiting resistor on the led. Again, probably not the cause of your problem, but something worth doing to avoid future problems.

edge87

I'm not sure i see what you mean. Do you mean a vertical jumper next to the yellow one? for some reason this bread board needs a jumper for positive but not negative as indicated by a solid black line and a red line with a missing gap (with a yellow jumper bridging them).

Mike Green

There's nothing wrong with your diagram. There must be something wrong with how you've wired it up.

With 10K resistors attached to 3.3V and DO / CLK / DI / CS, you should read +3.3V on those pins using a meter (because the meter doesn't draw significant current ... the voltage will be pulled up to 3.3V). This is whether or not an SD card is present. Similarly, when a card is inserted, the 10K pullups will indeed pull up the voltage to 3.3V. When you attach your 3.3V and ground to the SD card board, it should just sit there. Go over your wiring. Get a friend to go over it with you.

I've used SparkFun's SD card breakout board and their micro-SD card breakout board. Both have worked fine for me.

Dr_Acula

It sounds like a short somewhere if the power supply is cutting out. Shorts are nasty and my experience is that sometimes you have to pull all the wires out and start again. Build it up in stages, starting with the power supply/regulator, test the volts, add one chip, test the volts etc.

Tracing the wiring is a bit confusing on that photo - for instance a black wire (ground) turns into a red wire. Do you have enough wire to do all the ground in black, and all the 3V in red?

I suspect something around the regulator is not right but the photo cuts off at that edge. I'd like to see where the ground pin of the reg goes for instance.

I think you are close to getting it working - just a few tweaks here and there.

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www.smarthome.viviti.com/propeller

edge87

Is this plausible... can the card be defective? It is SUPER hot ( i mean it burned my hand ) and now it doesn't work in my computer. I'm going to run to a store and pickup another card and see if that resolve it. If it doesn't i'll remove everything and begin again.

If i use a computer power supply (supplying 3.3v off the 3.3 rail) can that hurt anything? I mean 3.3v is 3.3 volts right?

soshimo

edge87 said...
Is this plausible... can the card be defective? It is SUPER hot ( i mean it burned my hand ) and now it doesn't work in my computer. I'm going to run to a store and pickup another card and see if that resolve it. If it doesn't i'll remove everything and begin again.

If i use a computer power supply (supplying 3.3v off the 3.3 rail) can that hurt anything? I mean 3.3v is 3.3 volts right?

Read what Dr Acula wrote above. You definitely have a short. Heat means current usually. Your little SD card shouldn't be pulling too much current so you have a short somewhere. As Dr Acula wrote, check your wiring, tear everything down but the PS and check that. Build it up in blocks and make sure each block is good before moving to the next. Also, check your soldering on the breakout board. Look for any solder bridges especially. I soldered a header on mine, but that's personal preference.

One final thing, I would NOT hook that up to your computer or connect your USB 3.3v rail to in anywhere until you resolve your issue. If you have a short you risk shorting your USB 3.3v. The outcome of that can't be good for either your FTDI board or your computer.

I attached a photo of a working prototype that I am building. It's completely breadboarded as you can see and I have no issues with my SD card.

Post Edited (soshimo) : 7/18/2010 1:56:36 AM GMT

Dr_Acula

Super hot is not good [noparse]:([/noparse]

Yes, 3V is 3V, but 3V from a PC supply could be 20 amps if there is a short.

There may be an argument for running this from batteries while you get it working. Use zinc or alkaline (not rechargeables though as they can supply just as much current as a PC supply).

At least if you get a short and you are running on batteries, the supply tends to collapse and the circuit stops running but at least it is less likely to get really hot and destroy things.

Many electronic components will form a short if they are connected the wrong way. Then the next time you go to power up, there is now a short that was not there before. It could have been the briefest touch of a wire that caused the short. Even static.

I do hope your propeller chip is still ok?

If the problem only occurs when you connect the sd card, I guess you need to find out if it is the card holder or the card itself. Can you take the card out of the holder, disconnect the holder from your circuit, and measure the resistance between Gnd and the 3V wire. You should get over 10 megohms with nothing connected.

(it may be not wise to test for continuity with the card inserted - ok if your multimeter uses a 1.5V battery for continuity like some old-school ones did, but not so good if like most, they use a 9V battery. That can put 9V on a 3V SD card and might zap it if you have it on the wrong ohms setting)

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www.smarthome.viviti.com/propeller

Post Edited (Dr_Acula) : 7/18/2010 4:29:50 AM GMT

Toby Seckshund

I got the wiring to a SD connector offset by one pin (it was a different one to my usual). The sd got hot and died, another card which I put 9V up got hot but didn't die. All these problems occur when rushing to get something working, and not "check, check ...... again".

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Why did I think a new, more challenging, job was a good idea ??

edge87

I took the "rewire" it approach and replaced the sd card. The excess heat and short circuit seem to be gone. However the application still fails to work. (here is the test object i'm using from the OE http://obex.parallax.com/objects/92/ )

every time i run the test object. it fails with "Erroneously returned from start!" ""Mount failed spectacularly!" "Command => Response" . Has anybody else used this object and understands what this is a sign of? or has anybody a suggestion for a different test object?