LPC1768 SDC Problem

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 04:32:20 MST 2013
  Hi,

I am using LPC1768 with SDCard Application. I am using FATFS drivers. SDC interface some times not returning properly..it is working abt 15 days, after that is not working again i remove the card then put it back agian then it is started working. any Solun for this problem???


Regards,
Saravanan

[lpcware]

Content originally posted in LPCWare by capiman on Tue Sep 24 06:30:34 MST 2013
Look into your schematic and hardware, i don't know i a switch is possibly for micro SDC.
Search for microsd connectors and look for the switch or ask manufacturer like Amphenol and others.

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 06:27:30 MST 2013
we are using micro SDC only... anything switch is there for MicroSD also?

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 06:26:01 MST 2013
Okay capiman,

Thanks for ur reply

[lpcware]

Content originally posted in LPCWare by capiman on Tue Sep 24 06:21:26 MST 2013
Have a look into your schematic...
Have a look onto your hardware if there is a small switch inside SD card connector which is connected to you LPC1768.
If there is no switch, you just fail on accessing SD card and you must try to recover.
Don't know if this is possible in your hardware. Therefore i suggested the power switch for your SD card's power supply.

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 06:17:26 MST 2013
how to check SDC insertion detection?

[lpcware]

Content originally posted in LPCWare by capiman on Tue Sep 24 06:15:03 MST 2013
I really don't know.
Do you use sdcard insert detection? If not, you can remove the SD card when uC is on and see if it continues to write to SD card, when you re-insert the sdcard...Does it survive this kind of interruption? This could be one test...

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 06:10:34 MST 2013
suppose if i shutdown the m/c for every 15 min cycle( ON for 3 mins then OFF for 12 min like that), then any power loose or commu error will come??

[lpcware]

Content originally posted in LPCWare by capiman on Tue Sep 24 06:01:37 MST 2013
When it is broken, why shall it work after re-inserting? Have you repaired before re-inserting? I don't think so.
What could happen that data on SD card is broken, but then your software can detect and handle it.
It does not get repaired (if there is no automatic repair mechanism), so it is broken each time when you (re-)insert?

I assume that just SPI communication is not working. Perhaps SD card get looses its power supply for a short moment
and reset, so it is not prepared to communicate via SPI with LPC1768.

Analyzing 10 days is not a long time, when saying that error occurs only every 15 days. So you have seen it only once?
Or have you multiple devices and each of them is having the problem exactly after 15 days?
Make perhaps a statistic, perhaps it helps you.

Otherwise i can only suggest what i already have written in first answer.

[lpcware]

Content originally posted in LPCWare by saravanan on Tue Sep 24 05:45:54 MST 2013
Thanks for ur reply... there is no timer thing and all. before starting the task i am writing some test files to check whether SDC is ok or not. it working fine while debugging and running. but some times it is not working and the file open also showing error.. if there is any possible SDC corruption??

after this problem it is not working while debugging also. when remove and put back then it is started working. i am struggling for this problem from last 10 days., i cant find out the solns. what are the possibles for SDC corruption??

[lpcware]

Content originally posted in LPCWare by capiman on Tue Sep 24 04:50:07 MST 2013
Hello Saravanan,

i think only you can analyze the problem, because we have much too less details. Perhaps something else is disturbing the communication?
Perhaps you can add a logic analyzer to save the last action and signals before the error happens. But it could also happen,
that when you add the logic analyzer, the error does not occur anymore...
Solution could be to add a switch to power supply of SD card, so the LPC1768 can power down/up (reset) the SD card in case there is
a communication error.

Another hint: Is there perhaps a timer running in your software, which runs over and triggers some malfunction?

Good luck!

Best regards,

Martin