Connect Memory Card using PIC18F4520 Code

• 0 – if MMC/SD card was detected and successfully initialized
• 1 – otherwise

• Mmc_Chip_Select: Chip Select line
• Mmc_Chip_Select_Direction: Direction of the Chip Select pin

must be defined before using this function. The appropriate hardware SPI module must be previously initialized. See the SPI1_Init, SPI1_Init_Advanced routines.

// MMC module connections 
sfr sbit Mmc_Chip_Select at RC0_bit;
sfr sbit Mmc_Chip_Select_Direction at TRISC0_bit;
// MMC module connections
...
SPI1_Init();

error = Mmc_Init();  // Init with CS line at RC0_bit

• 0 – if reading was successful
• 1 – if an error occurred

• sector: MMC/SD card sector to be read.
• dbuff: buffer of minimum 512 bytes in length for data storage.

// read sector 510 of the MMC/SD card
unsigned int error;
unsigned long sectorNo = 510;
char dataBuffer[512];
...
error = Mmc_Read_Sector(sectorNo, dataBuffer);

• 0 – if writing was successful
• 1 – if there was an error in sending write command
• 2 – if there was an error in writing (data rejected)

• sector: MMC/SD card sector to be written to.
• dbuff: data to be written (buffer of minimum 512 bytes in length).

// write to sector 510 of the MMC/SD card
unsigned int error;
unsigned long sectorNo = 510;
char dataBuffer[512];
...
error = Mmc_Write_Sector(sectorNo, dataBuffer);

• 0 – if CID register was read successfully
• 1 – if there was an error while reading

• data_cid: buffer of minimum 16 bytes in length for storing CID register content.

unsigned int error;
char dataBuffer[16];
...
error = Mmc_Read_Cid(dataBuffer);

• 0 – if CSD register was read successfully
• 1 – if there was an error while reading

• data_csd: buffer of minimum 16 bytes in length for storing CSD register content.

unsigned int error;
char dataBuffer[16];
...
error = Mmc_Read_Csd(dataBuffer);

• sector: starting sector number.

• 0 – if multi read start was successful.
• 1 – ir error occured.

unsigned int error;
char sector;
...
error = Mmc_Multi_Read_Start(sector);

• dbuff: buffer for holding the sector data.

unsigned int error;
...
Mmc_Multi_Read_Sector(buffer);

• 0 – if stop was successful.
• 1 – ir error was detected.

Mmc_Multi_Read_Stop;

• 0 – if MMC/SD card was detected and successfully initialized
• 1 – if FAT16 boot sector was not found
• 255 – if MMC/SD card was not detected

• Mmc_Chip_Select: Chip Select line
• Mmc_Chip_Select_Direction: Direction of the Chip Select pin

must be defined before using this function. The appropriate hardware SPI module must be previously initialized.

// MMC module connections 
sfr sbit Mmc_Chip_Select at RC0_bit;
sfr sbit Mmc_Chip_Select_Direction at TRISC0_bit;
// MMC module connections

// Initialize SPI1 module
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV64, _SPI_DATA_SAMPLE_MIDDLE,_SPI_CLK_IDLE_LOW, _SPI_LOW_2_HIGH);

// use fat16 quick format instead of init routine if a formatting is needed
if (!Mmc_Fat_Init()) {
// reinitialize SPI1 at higher speed
SPI1_Init_Advanced(_SPI_MASTER_OSC_DIV4, _SPI_DATA_SAMPLE_MIDDLE, _SPI_CLK_IDLE_LOW, _SPI_LOW_2_HIGH);
...
}

• 0 – if MMC/SD card was detected, successfully formated and initialized
• 1 – if FAT16 format was unsuccessful
• 255 – if MMC/SD card was not detected

• mmc_fat_label: volume label (11 characters in length). If less than 11 characters are provided, the label will be padded with spaces. If null string is passed volume will not be labeled

// Format and initialize MMC/SD card and MMC_FAT16 library globals
if (!Mmc_Fat_QuickFormat(&mmc_fat_label)) {
...
}

• 2 – if there are no more free file handlers, currently opened file is closed in order to free space.
• 1 – if file already exists or file does not exist but a new file is created.
• 0 – if file does not exist and no new file is created.

• filename: name of the file that should be assigned for file operations. File name should be in DOS 8.3 (file_name.extension) format. The file name and extension will be automatically padded with spaces by the library if they have less than length required (i.e. “mikro.tx” -> “mikro .tx “), so the user does not have to take care of that. The file name and extension are case insensitive. The library will convert them to proper case automatically, so the user does not have to take care of that.
• file_cre_attr: file creation and attributs flags. Each bit corresponds to the appropriate file attribut:
  

  Bit	Mask	Description
  0	0x01	Read Only
  1	0x02	Hidden
  2	0x04	System
  3	0x08	Volume Label
  4	0x10	Subdirectory
  5	0x20	Archive
  6	0x40	Device (internal use only, never found on disk)
  7	0x80	File creation flag. If file does not exist and this flag is set, a new file with specified name will be created.

    Note : Long File Names (LFN) are not supported.

// create file with archive attribute if it does not already exist
Mmc_Fat_Assign("MIKRO007.TXT",0xA0);

• size: buffer to store file size to. After file has been open for reading, its size is returned through this parameter.

unsigned long size;
...
Mmc_Fat_Reset(&size);

• bdata: buffer to store read byte to. Upon this function execution read byte is returned through this parameter.

char character;
...
Mmc_Fat_Read(&character);

// open file for writing
Mmc_Fat_Rewrite();

// open file for appending
Mmc_Fat_Append();

• 1 – if there are no assigned files
• 2 – if an error occured during deleting
• 0 – if deleting was successful

// delete current file
if (Mmc_Fat_Delete() == 0)
...

• fdata: data to be written.
• data_len: number of bytes to be written.

Mmc_Fat_Write(txt,255);
Mmc_Fat_Write("Hello world",255);

• year: year attribute. Valid values: 1980-2107
• month: month attribute. Valid values: 1-12
• day: day attribute. Valid values: 1-31
• hours: hours attribute. Valid values: 0-23
• mins: minutes attribute. Valid values: 0-59
• seconds: seconds attribute. Valid values: 0-59

// April 1st 2005, 18:07:00
Mmc_Fat_Set_File_Date(2005, 4, 1, 18, 7, 0);

• year: buffer to store year attribute to. Upon function execution year attribute is returned through this parameter.
• month: buffer to store month attribute to. Upon function execution month attribute is returned through this parameter.
• day: buffer to store day attribute to. Upon function execution day attribute is returned through this parameter.
• hours: buffer to store hours attribute to. Upon function execution hours attribute is returned through this parameter.
• mins: buffer to store minutes attribute to. Upon function execution minutes attribute is returned through this parameter.

// get Date/time of file
unsigned yr;
char mnth, dat, hrs, mins;
...
file_Name = "MYFILEABTXT";
Mmc_Fat_Assign(file_Name);
Mmc_Fat_Get_File_Date(&yr, &mnth, &day, &hrs, &mins);

• year: buffer to store year of modification attribute to. Upon function execution year of modification attribute is returned through this parameter.
• month: buffer to store month of modification attribute to. Upon function execution month of modification attribute is returned through this parameter.
• day: buffer to store day of modification attribute to. Upon function execution day of modification attribute is returned through this parameter.
• hours: buffer to store hours of modification attribute to. Upon function execution hours of modification attribute is returned through this parameter.
• mins: buffer to store minutes of modification attribute to. Upon function execution minutes of modification attribute is returned through this parameter.

// get modification Date/time of file
unsigned yr;
char mnth, dat, hrs, mins;
...
file_Name = "MYFILEABTXT";
Mmc_Fat_Assign(file_Name);
Mmc_Fat_Get_File_Date_Modified(&yr, &mnth, &day, &hrs, &mins);

// get Date/time of file
unsigned yr;
char mnth, dat, hrs, mins;
...
file_name = "MYFILEXXTXT";
Mmc_Fat_Assign(file_name);
mmc_size = Mmc_Fat_Get_File_Size;

unsigned long sector;
...
sector = Mmc_Get_File_Write_Sector();

• Number of the start sector for the newly created swap file, if there was enough free space on the MMC/SD card to create file of required size.
• 0 – otherwise.

• sectors_cnt: number of consecutive sectors that user wants the swap file to have.
• filename: name of the file that should be assigned for file operations. File name should be in DOS 8.3 (file_name.extension) format. The file name and extension will be automatically padded with spaces by the library if they have less than length required (i.e. “mikro.tx” -> “mikro .tx “), so the user does not have to take care of that. The file name and extension are case insensitive. The library will convert them to proper case automatically, so the user does not have to take care of that. Also, in order to keep backward compatibility with the first version of this library, file names can be entered as UPPERCASE string of 11 bytes in length with no dot character between file name and extension (i.e. “MIKROELETXT” -> MIKROELE.TXT). In this case the last 3 characters of the string are considered to be file extension.
• file_attr: file creation and attributs flags. Each bit corresponds to the appropriate file attribut:
  

  Bit	Mask	Description
  0	0x01	Read Only
  1	0x02	Hidden
  2	0x04	System
  3	0x08	Volume Label
  4	0x10	Subdirectory
  5	0x20	Archive
  6	0x40	Device (internal use only, never found on disk)
  7	0x80	Not used

    Note : Long File Names (LFN) are not supported.

//-------------- Tries to create a swap file, whose size will be at least 100 sectors.
//If it succeeds, it sends the No. of start sector over UART
void M_Create_Swap_File(){
  size = Mmc_Fat_Get_Swap_File(100);
  if (size <> 0) {
    UART1_Write(0xAA);
    UART1_Write(Lo(size));
    UART1_Write(Hi(size));
    UART1_Write(Higher(size));
    UART1_Write(Highest(size));
    UART1_Write(0xAA);
  } 
}