Difference between revisions of "MMC Card Reader Development"

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*stdio.h has no equivalent '''FRESULT'''
 
*stdio.h has no equivalent '''FRESULT'''
 
|-
 
|-
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| Read || 7.73 || 30 ||
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| Read  
 +
|  
 +
  size_t
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[http://www.cplusplus.com/reference/clibrary/cstdio/fread/ fread] (
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  void * ptr,
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  size_t size,
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  size_t count,
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  FILE * stream
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);
 +
|
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  FRESULT
 +
[http://elm-chan.org/fsw/ff/en/read.html f_read] (
 +
  FIL* FileObject,    /* Pointer to the file object structure */
 +
  void* Buffer,      /* Pointer to the buffer to store read data */
 +
  UINT ByteToRead,    /* Number of bytes to read */
 +
  UINT* ByteRead      /* Pointer to the variable to return number of bytes read */
 +
);
 +
|
 +
*'''size_t''' matches '''ByteRead'''
 +
*'''ptr''' matches '''Buffer'''
 +
*'''count''' matches '''ByteToRead'''
 +
*'''stream''' matches '''FileObject'''
 +
*stdio.h has no equivalent '''FRESULT'''
 
|-
 
|-
−
| Write || 7.85 || 30 ||
+
| Write
 +
|
 +
  size_t
 +
[http://www.cplusplus.com/reference/clibrary/cstdio/fwrite/ fwrite] (
 +
  const void * ptr,
 +
  size_t size,
 +
  size_t count,
 +
  FILE * stream
 +
);
 +
|  
 +
  FRESULT
 +
[http://elm-chan.org/fsw/ff/en/write.html f_write] (
 +
  FIL* FileObject,    /* Pointer to the file object structure */
 +
  const void* Buffer,  /* Pointer to the data to be written */
 +
  UINT ByteToWrite,    /* Number of bytes to write */
 +
  UINT* ByteWritten    /* Pointer to the variable to return number of bytes written */
 +
);
 +
|
 +
*'''size_t''' matches '''ByteWritten'''
 +
*'''ptr''' matches '''Buffer'''
 +
*'''count''' matches '''ByteToWrite'''
 +
*'''stream''' matches '''FileObject'''
 +
*stdio.h has no equivalent '''FRESULT'''
 
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|-  
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| Close || 4.62 || 40 ||
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| Close
−
|-
+
|
−
| Seek || 4.81 || 40 ||
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  int
 +
[http://www.cplusplus.com/reference/clibrary/cstdio/fclose/ fclose] (
 +
  FILE * stream
 +
);
 +
|
 +
  FRESULT
 +
[http://elm-chan.org/fsw/ff/en/close.html f_close] (
 +
  FIL* FileObject    /* Pointer to the file object structure */
 +
);
 +
|
 +
*'''int''' matches '''FRESULT'''
 +
*'''stream''' matches '''FileObject'''
 
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Revision as of 19:43, 25 August 2009

This wiki describes the development of the MMC Card Reader Project

Architecture

  • See here for block diagram


Development Roadmap

Phase 1

  • Create stdio.h wrapper for file system in freertos_posix
  • Use existing I2C EEPROM driver for development

Phase 2

  • Circuit design for interfacing MMC

Phase 3

  • SPI driver for MMC

Phase 4

  • Test for normal read/write function
  • hotswap (should not hang or cause voltage dip)
  • multiple file read/write (protection)


Circuit and PCB


Software Implementation

Comparison of FatFs and stdio API

  • selected list is described below
Comparison between FatFs and stdio API
Function stdio.h FatFs Remarks
Open 
 FILE *

fopen ( 

 const char * filename, 
 const char * mode

); 

 FRESULT

f_open ( 

 FIL* FileObject,       /* Pointer to the blank file object structure */
 const XCHAR* FileName, /* Pointer to the file neme */
 BYTE ModeFlags         /* Mode flags */

);

  • FILE matches FIL
  • filename matches FileName
  • mode matches ModeFlags
  • stdio.h has no equivalent FRESULT
Read 
 size_t

fread ( 

 void * ptr, 
 size_t size, 
 size_t count, 
 FILE * stream

); 

 FRESULT

f_read ( 

 FIL* FileObject,    /* Pointer to the file object structure */
 void* Buffer,       /* Pointer to the buffer to store read data */
 UINT ByteToRead,    /* Number of bytes to read */
 UINT* ByteRead      /* Pointer to the variable to return number of bytes read */

);

  • size_t matches ByteRead
  • ptr matches Buffer
  • count matches ByteToRead
  • stream matches FileObject
  • stdio.h has no equivalent FRESULT
Write 
 size_t

fwrite ( 

 const void * ptr, 
 size_t size, 
 size_t count, 
 FILE * stream

); 

 FRESULT

f_write ( 

 FIL* FileObject,     /* Pointer to the file object structure */
 const void* Buffer,  /* Pointer to the data to be written */
 UINT ByteToWrite,    /* Number of bytes to write */
 UINT* ByteWritten    /* Pointer to the variable to return number of bytes written */

);

  • size_t matches ByteWritten
  • ptr matches Buffer
  • count matches ByteToWrite
  • stream matches FileObject
  • stdio.h has no equivalent FRESULT
Close 
 int

fclose ( 

 FILE * stream

); 

 FRESULT

f_close ( 

 FIL* FileObject     /* Pointer to the file object structure */

);

  • int matches FRESULT
  • stream matches FileObject
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