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tsupuntu
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| Why PIC can't read file witch name more than 8 charater |
 Posted: Fri May 05, 2006 5:38 am |
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| Why PIC can't read file witch name more than 8 charater or lower character in MMC card. Please suggest me.thank in advance. |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri May 05, 2006 6:13 am |
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Which MMC library are you using?
If it is a library supplied by CCS then also tell us the CCS compiler version you are using. |
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tsupuntu
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| Posted: Fri May 05, 2006 6:40 am |
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| ckielstra wrote: | Which MMC library are you using?
If it is a library supplied by CCS then also tell us the CCS compiler version you are using. |
I use driver mmc card for this WEB .I use compiler version 3.245 |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri May 05, 2006 6:48 am |
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| Quote: | | I use driver mmc card for this WEB . |
Sorry, but I don't understand this. Can you be a bit more specific? Where did you find the software? Can you provide a link to it? |
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tsupuntu
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| Posted: Fri May 05, 2006 10:01 pm |
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| ckielstra wrote: | | Quote: | | I use driver mmc card for this WEB . |
Sorry, but I don't understand this. Can you be a bit more specific? Where did you find the software? Can you provide a link to it? |
I use driver in link in library this WEB
I know Fat16 can create file name maximum 8 character but windows can create file name more than 8 character.
My project is create file form PC and name of file more than 8 character. Then I use PIC18F458 read file show in hyperterminal.
But can not find the file name more than 8 character.
Why PC can create file name more than 8 character?. Please suggest me.
Thank in advance. |
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Douglas Kennedy
Joined: 07 Sep 2003
Posts: 755
Location: Florida
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| Posted: Sat May 06, 2006 7:45 am |
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The FAT file system is fully owned by Microsoft and this response in no way is intended to encourage violations of Microsofts ownership.
DOS used 8.3 file names ( 8characters of the name . 3 characters of an extension). Longer names were added by making the "tile" ( the word tile may be copyrighted by Microsoft but it is used here for clarity only) which contained only the 8.3 name into mutiple tiles so that the multiple tiles can contain the long name. Check on the copyright issue but you might be lawfully able to write your own code on the PIC to validate the longer name in the other tiles. DOS has 8.3 less legal restrictions than long file names features. Reading Microsoft FAT files may have less legal issues than writing them but check with your attorney. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sat May 06, 2006 12:02 pm |
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I was surprised to learn about the FAT file system patent from your post.
I did a web search and found this was a recent decision by the U.S. Patent Office in January 2006.
Here's a Wikipedia article on it.
http://en.wikipedia.org/wiki/File_Allocation_Table#FAT_licensing
The Wikipedia article makes this comment:
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Many technical commentators have concluded that these patents only
cover FAT implementations that include support for long filenames, and
that removable solid state media and consumer devices only using short
names would be unaffected.
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Here's a Linux discussion forum where they talk about how this patent
will affect existing users of the technology. They discuss Microsoft's
motivations and how they might enforce the patent.
http://lwn.net/Articles/167180/ |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Sat May 06, 2006 12:03 pm |
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| tsupuntu wrote: | | ckielstra wrote: | | Quote: | | I use driver mmc card for this WEB . |
Sorry, but I don't understand this. Can you be a bit more specific? Where did you find the software? Can you provide a link to it? |
I use driver in link in library this WEB |
I don't want to sound like I'm repeating myself, but I still have no clue as to which library you are relating to. If you mean with 'this WEB' the CCS forum then I still have no clue because there have been multiple disussions / postings. Please post a link to the library you are talking about (go to the page, copy the link from the top of your browser and paste it here). |
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tsupuntu
Joined: 05 May 2006
Posts: 9
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| Thank |
| Posted: Sat May 06, 2006 7:47 pm |
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| ckielstra wrote: | | tsupuntu wrote: | | ckielstra wrote: | | Quote: | | I use driver mmc card for this WEB . |
Sorry, but I don't understand this. Can you be a bit more specific? Where did you find the software? Can you provide a link to it? |
I use driver in link in library this WEB |
I don't want to sound like I'm repeating myself, but I still have no clue as to which library you are relating to. If you mean with 'this WEB' the CCS forum then I still have no clue because there have been multiple disussions / postings. Please post a link to the library you are talking about (go to the page, copy the link from the top of your browser and paste it here). |
Thank for every body..........
libraly this link.
http://www.ccsinfo.com/forum/viewtopic.php?t=21721 |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Re: Why PIC can't read file witch name more than 8 charater |
| Posted: Sun May 07, 2006 3:22 pm |
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| tsupuntu wrote: | | Why PIC can't read file witch name more than 8 charater or lower character in MMC card. Please suggest me.thank in advance. |
In the long history of Microsoft several file systems have been created, one of the oldest is the FAT16 file system. The MMC library you refer to uses this old file system. FAT 16 is relatively simple to implement but has the limitations of the 8.3 names (8 characters before the point character and 3 after the point). Other limitations are a maximum of 32Mbyte memory size.
For what you want to do the FAT16 file system is not sufficient, you'll need a FAT32 implementation. FAT32 was introduced with Windows-95 and has support for long file names and memory sizes up to 2Gbyte.
I don't know where you can find a ready to use FAT32 library for the PIC, maybe someone else can give you a pointer?
For a detailed technical description of the FAT32 file system you can go to http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Re: Why PIC can't read file witch name more than 8 charater |
| Posted: Sun May 07, 2006 3:47 pm |
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| ckielstra wrote: | | tsupuntu wrote: | | Why PIC can't read file witch name more than 8 charater or lower character in MMC card. Please suggest me.thank in advance. |
In the long history of Microsoft several file systems have been created, one of the oldest is the FAT16 file system. The MMC library you refer to uses this old file system. FAT 16 is relatively simple to implement but has the limitations of the 8.3 names (8 characters before the point character and 3 after the point). Other limitations are a maximum of 32Mbyte memory size.
For what you want to do the FAT16 file system is not sufficient, you'll need a FAT32 implementation. FAT32 was introduced with Windows-95 and has support for long file names and memory sizes up to 2Gbyte.
I don't know where you can find a ready to use FAT32 library for the PIC, maybe someone else can give you a pointer?
For a detailed technical description of the FAT32 file system you can go to http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx |
Long filenames were made possible in FAT16 by adding phoney entries into the directory table. |
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