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Author Topic: Trouble reading SD card
adrigax
Newbie
Posts: 13
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Post Trouble reading SD card
on: December 29, 2013, 00:41
Quote

Hi, I'm experiencing some trouble with the SD card reader of my new Polargraph.

When I try to stick my SD card in the Polargraph and hit the "draw from SD" button, the only thing written (where the filenames should appear) is the word "none". Exactly like when there's no card at all...

I've tried formatting the SD card with a mac and wit a PC, both in FAT 32 and 16 but it's still the same thing.

What am I missing there? Has anyone experienced this?

Thanks!

Adrien

sandy
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Posts: 1427
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sandy
Post Re: Trouble reading SD card
on: December 29, 2013, 00:46
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Hallo, not sure if you're already doing it but you need to restart the machine with the SD card in-place to see what's there. It only reads the card once, on startup.

That, and it's normal to have "none" displayed initially (it actually means that there is no script file currently selected) - pressing "next" and "prev" should show the others on the SD card.

As far as formatting - I've never done anything special with mine, but I use a windows PC usually. It needs a FAT format card (FAT32 I guess).

good luck!
sn

adrigax
Newbie
Posts: 13
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Post Re: Trouble reading SD card
on: December 29, 2013, 06:18
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Hello,
yes unfortunately I've already tried everything you suggest. For some weird reason my Polargraph carry on pretending the SD card is empty...
If you have any other ideas, I'll be glad to read them 🙂 I keep faith, I keep looking for the solution!

Adrien

kongorilla
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Posts: 385
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kongorilla
Post Re: Trouble reading SD card
on: December 29, 2013, 07:37
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Your exported queue files have a .txt extension? They're in the root of the SD card? They're named with alphanumeric characters only? (I'm clutching at straws -- I thought for sure you hadn't hit "next" when you saw "none" until you answered you tried that. I got tripped up with that when I first tried using the SD).

sandy
Administrator
Posts: 1427
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sandy
Post Re: Trouble reading SD card
on: December 29, 2013, 11:03
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Have a look at the serial output that occurs when the machine is started up, to see if there are any errors, or messages. Normally, if there's no card in, it will send out something like "Card failed or not present". If there is a card, it will do some more diagnosis (with messages), and if it can find any files on the card, then it'll list them.

You can get to the serial output either by connecting to the polargraph controller and pressing ctrl-c (for Console), or you can use the serial port monitor in the Arduino IDE at 57600 baud.

Only other thing I can think I've had problems with is long filenames, 8 chars is max. I would have assumed that longer ones are just truncated (in that LONGFI~1.txt way that windows does)... But typing that, of course this mini-FAT system is not windows, and I do remember the long filenames being an "aha" moment. Give it a shot anyway, perhaps you've already tried it.

sn

adrigax
Newbie
Posts: 13
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Post Re: Trouble reading SD card
on: December 29, 2013, 12:07
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Oh thanks for telling me about the serial output. Here's the messages I get :

incoming: card initialized.
incoming: Initializing SD card...
incoming: Wiring is correct and a card is present.
incoming:
incoming: Card type: SDHC
incoming: Could not find FAT16/FAT32 partition.
incoming: Make sure you've formatted the card

... which is strange because I tried many ways of formatting the card (both with mac and PC) and it keeps telling me that! Do you thing there might be an issue with the way I uploaded the firmware or anything else?

Anyway, thanks a lot for your precise and quick answers on this forum. That's great!

Adrien

sandy
Administrator
Posts: 1427
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sandy
Post Re: Trouble reading SD card
on: December 29, 2013, 13:27
Quote

Hi Adrien, yep the serial output is very useful for debugging because there's not much communication exposed in the controller itself. Right I'm assuming the SD card is the one supplied in the kit - am guessing it's a 4GB one. Is there any chance you have a spare lower capacity SD card you could have a try with?

Historically PolargraphSDs have come with 2GB cards because larger cards have necessarily used SDHC, (high capacity) which is a slightly different method of access that _in principle_ the readers are less often compatible with. But now smaller cards are more expensive, so the last few machines have shipped with 4GB cards instead. I wasn't sure they would work the same, but my initial testing reassured me that it worked ok, so that's the background. I wonder if there's edge cases here though - hope not.

When the studio is open again next week I can post a 2GB one (I think I have a couple leftover) out if you don't have one, or you can buy one locally and send me the bill 🙂

Don't think there could be anything to do with the firmware, as far as I can think of, there aren't any options around the SD card reading to be changed. I'll have a look around and see if I can find other folks reporting any issues with the SD library and SDHC cards. Of course it's possible it's just a faulty card. But then you wouldn't be able to use it in a computer though, I guess.

sn

adrigax
Newbie
Posts: 13
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Post Re: Trouble reading SD card
on: December 29, 2013, 18:11
Quote

Oh yes! It's working!

I hadn't told you earlier but I had tried before with another SD card (512MB) which wasn't working either. In fact it was even more depressing because I got the message "Card failed or not present".

But...

I asked around me and my flatmate happened to have a SD card in her camera. It was a 4G as well but I said "anyway let's give it a try" because I wanted to persuade myself that I am a nice boy who ne baisse pas les bras si facilement, as we say in my country...
and it worked! So easily.

My new (working) card is a SanDisk, I don't know if the brand makes the difference but I'd rather use my energy discovering my Polargraph than tring to answer this question.

Anyway, thanks a lot and now for me it's time to try and make my first drawing. 🙂

Adrien

sandy
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Posts: 1427
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sandy
Post Re: Trouble reading SD card
on: December 29, 2013, 19:42
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Hm!! Well that's good news I suppose 🙂 Confusing though, I'll have to have a closer look at these 4GB cards...

Good luck!
sn

sandy
Administrator
Posts: 1427
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sandy
Post Re: Trouble reading SD card
on: January 5, 2014, 18:28
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Having had a closer look, the problem seems to be a combination of card and touchscreen panel. The SD card reader is incorporated into the touchscreen, and the values of the passive components on the back of the screen board have changed. I think it's significant, but it's also probably true that SDHC cards are just more sensitive. Mine behaves the same as yours when the PSU is connected at 7.5v (the default voltage setting). When powered by USB alone, or when the PSU is turned down to 5v, the card miraculously beings to work again.

So it's some kind of voltage issue, and there is a voltage divider there on the polarshield itself, so I'll try some different value parts in that position, and see if that makes it more reliable.

I wrote up a little post too. Adrien I will be posting out a (working) SD card in the next day or two. Thanks for being understanding!

sn

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