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Forum Index : Microcontroller and PC projects : Maximite-SM1 SD card locked, write error

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Greg Fordyce
Senior Member

Joined: 16/09/2011
Location: United Kingdom
Posts: 153
Posted: 09:01am 04 Oct 2011
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I recently purchased 2 SM1 maximites from Dontronics. Last night I tried the second Maximite and am having a problem writing to the SD card. Both MM have the same 2.6D and when using the same card and same simple 3 line program one of them won't let me write to the card, saying it is locked. I suspect a faulty SD card socket or soldering fault. Initial inspection shows nothing obvious and no damage to the socket. Is there an easy point to check the write protect terminal is working properly. There are some vias on the board near the sd socket, maybe one of them is for the write protect terminal?

GregEdited by Greg Fordyce 2011-10-05
 
Vikingboy
Regular Member

Joined: 23/09/2011
Location: Australia
Posts: 82
Posted: 04:29pm 04 Oct 2011
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Hi,

I have had quite some difficulty with SD cards, Just a couple of things i have noted:
I have one card which has a VERY loose write protect slider on the side, to the point that if I unlock it the process of simply sliding it into the SD card holder pushes it back into the locked position, solution I had was to tape or glue the lock protection in the open position.

Also I noticed something probably not directly concerned with your problem,

When using the LCD shield and testing the buttons on it, I noticed that the resistors returned different values to the pins when I powered the MM and LCD shield from my laptop compared to from an external 12V supply, On my laptop I was able to get the "select" button working fine by adjusting the values, this was impossible using external power. This made me realize that the power regulation was not absolute.
I then noticed that some files written to the SD card when on laptop power seemed to not be able to be read when I was powered of the external supply. I am not certain but it seems that the power difference affects the ability to read the files, trying to read them results in an error and the card has to be reinserted to be able to do a simple dir listing.

Hope you can solve your problems,

Andrew
 
donmck

Guru

Joined: 09/06/2011
Location: Australia
Posts: 1313
Posted: 10:11pm 04 Oct 2011
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  Greg Fordyce said   I recently purchased 2 SM1 maximites from Dontronics. Last night I tried the second Maximite and am having a problem writing to the SD card. Both MM have the same 2.6D and when using the same card and same simple 3 line program one of them won't let me write to the card, saying it is locked. I suspect a faulty SD card socket or soldering fault. Initial inspection shows nothing obvious and no damage to the socket. Is there an easy point to check the write protect terminal is working properly. There are some vias on the board near the sd socket, maybe one of them is for the write protect terminal?

Greg


Hi Greg,

drop an email to Richard, the designer and manufacturer, and he may be able to assist:
sales AT emx.net.au

Cheers Don...
https://www.dontronics.com
 
Greg Fordyce
Senior Member

Joined: 16/09/2011
Location: United Kingdom
Posts: 153
Posted: 10:23pm 04 Oct 2011
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Thanks Don, I have sent an email to Richard. I don't think it is a problem with the SD card and I checked the lock tab. I did notice something a bit unusual though. Even though the SD card is "locked", MMBasic will still create a file as per the following screen output.

> files
Directory: \
TEST.TXT 27
TEST1.TXT 0
TEST2.TXT 7
> 10 open "test3.txt" for append as #1
> list
10 OPEN "test3.txt" FOR append AS #1
20 PRINT #1, "howdee"
30 CLOSE #1
> run
Error line 20: File is read only
> files
Directory: \
TEST.TXT 27
TEST1.TXT 0
TEST2.TXT 7
TEST3.TXT 0
>
 
TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6096
Posted: 03:17am 05 Oct 2011
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Hi
I had a similar problem with my SM1 and it turned out to be a bad solder joint between the card holder and the PC board. I little bit of heat fixed it for me.

It is one of the two terminals on the left hand side towards the front.

Jim.
VK7JH
MMedit   MMBasic Help
 
Greg Fordyce
Senior Member

Joined: 16/09/2011
Location: United Kingdom
Posts: 153
Posted: 09:00pm 08 Oct 2011
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Problem fixed, it was a poor solder joint at the SD card holder.
 
donmck

Guru

Joined: 09/06/2011
Location: Australia
Posts: 1313
Posted: 09:28pm 08 Oct 2011
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  Greg Fordyce said   Problem fixed, it was a poor solder joint at the SD card holder.



Thanks for the feed back Greg, great find. I'll let Richard know.

Cheers Don...
https://www.dontronics.com
 
sparkey

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 819
Posted: 02:18am 09 Oct 2011
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first thing i would have checked ...in all my experence`s with electronics no matter what you do or change the fist thing to look for is crook solder joints ....if it aint connected it ant gunna work....regards sparkey....
technicians do it with least resistance
 
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