ElectRoidWarE: Connect Memory Card with ATmega128 Code

The Compact Flash Library provides routines for accessing data on Compact Flash card. CF cards are widely used memory elements, commonly used with digital cameras. Great capacity and excellent access time of only a few microseconds make them very attractive for microcontroller applications.
In CF card, data is divided into sectors. One sector usually comprises 512 bytes. Routines for file handling, the Cf_Fat routines, are not performed directly but successively through 512B buffer.

Important :

Routines for file handling can be used only with FAT16 file system.
Library functions create and read files from the root directory only.
Library functions populate both FAT1 and FAT2 tables when writing to files, but the file data is being read from the FAT1 table only; i.e. there is no recovery if the FAT1 table gets corrupted.
If MMC/SD card has Master Boot Record (MBR), the library will work with the first available primary (logical) partition that has non-zero size. If MMC/SD card has Volume Boot Record (i.e. there is only one logical partition and no MBRs), the library works with entire card as a single partition. For more information on MBR, physical and logical drives, primary/secondary partitions and partition tables, please consult other resources, e.g. Wikipedia and similar.
Before writing operation, make sure not to overwrite boot or FAT sector as it could make your card on PC or digital camera unreadable. Drive mapping tools, such as Winhex, can be of great assistance.

External dependencies of Compact Flash Library

The following variables must be defined in all projects using Compact Flash Library:	Description :	Example :
`extern sfr char CF_Data_Port;`	Compact Flash Data Port.	`char CF_Data_Port at PORTD;`
`extern sfr char CF_Data_Port_Direction;`	Direction of the Compact Flash Data Port.	`char CF_Data_Port_Direction at DDRD;`
`extern sfr sbit CF_RDY;`	Ready signal line.	`sbit CF_RDY at PINB7_bit;`
`extern sfr sbit CF_WE;`	Write Enable signal line.	`sbit CF_WE at PORTB6_bit;`
`extern sfr sbit CF_OE;`	Output Enable signal line.	`sbit CF_OE at PORTB5_bit;`
`extern sfr sbit CF_CD1;`	Chip Detect signal line.	`sbit CF_CD1 at PINB4_bit;`
`extern sfr sbit CF_CE1;`	Chip Enable signal line.	`sbit CF_CE1 at PORTB3_bit;`
`extern sfr sbit CF_A2;`	Address pin 2.	`sbit CF_A2 at PORTB2_bit;`
`extern sfr sbit CF_A1;`	Address pin 1.	`sbit CF_A1 at PORTB1_bit;`
`extern sfr sbit CF_A0;`	Address pin 0.	`sbit CF_A0 at PORTB0_bit;`
`extern sfr sbit CF_RDY_direction;`	Direction of the Ready pin.	`sbit CF_RDY_direction at DDB7_bit;`
`extern sfr sbit CF_WE_direction;`	Direction of the Write Enable pin.	`sbit CF_WE_direction at DDB6_bit;`
`extern sfr sbit CF_OE_direction;`	Direction of the Output Enable pin.	`sbit CF_OE_direction at DDB5_bit;`
`extern sfr sbit CF_CD1_direction;`	Direction of the Chip Detect pin.	`sbit CF_CD1_direction at DDB4_bit;`
`extern sfr sbit CF_CE1_direction;`	Direction of the Chip Enable pin.	`sbit CF_CE1_direction at DDB3_bit;`
`extern sfr sbit CF_A2_direction;`	Direction of the Address 2 pin.	`sbit CF_A2_direction at DDB2_bit;`
`extern sfr sbit CF_A1_direction;`	Direction of the Address 1 pin.	`sbit CF_A1_direction at DDB1_bit;`
`extern sfr sbit CF_A0_direction;`	Direction of the Address 0 pin.	`sbit CF_A0_direction at DDB0_bit;`

Library Routines

Cf_Init
Cf_Detect
Cf_Enable
Cf_Disable
Cf_Read_Init
Cf_Read_Byte
Cf_Write_Init
Cf_Write_Byte
Cf_Read_Sector
Cf_Write_Sector

Routines for file handling:

Cf_Fat_Init
Cf_Fat_QuickFormat
Cf_Fat_Assign
Cf_Fat_Reset
Cf_Fat_Read
Cf_Fat_Rewrite
Cf_Fat_Append
Cf_Fat_Delete
Cf_Fat_Write
Cf_Fat_Set_File_Date
Cf_Fat_Get_File_Date
Cf_Fat_Get_File_Date_Modified
Cf_Fat_Get_File_Size
Cf_Fat_Get_Swap_File

The following routine is for the internal use by compiler only:

Cf_Issue_ID_Command

Cf_Init

Prototype	void Cf_Init();
Returns	Nothing.
Description	Initializes ports appropriately for communication with CF card.
Requires	Global variables : `CF_Data_Port` : Compact Flash data port `CF_RDY` : Ready signal line `CF_WE` : Write enable signal line `CF_OE` : Output enable signal line `CF_CD1` : Chip detect signal line `CF_CE1` : Enable signal line `CF_A2` : Address pin 2 `CF_A1` : Address pin 1 `CF_A0` : Address pin 0 `CF_Data_Port_direction` : Direction of the Compact Flash data direction port `CF_RDY_direction` : Direction of the Ready pin `CF_WE_direction` : Direction of the Write enable pin `CF_OE_direction` : Direction of the Output enable pin `CF_CD1_direction` : Direction of the Chip detect pin `CF_CE1_direction` : Direction of the Chip enable pin `CF_A2_direction` : Direction of the Address 2 pin `CF_A1_direction` : Direction of the Address 1 pin `CF_A0_direction` : Direction of the Address 0 pin must be defined before using this function.
Example	// set compact flash pinout char Cf_Data_Port at PORTD; sbit CF_RDY at PINB7_bit; sbit CF_WE at PORTB6_bit; sbit CF_OE at PORTB5_bit; sbit CF_CD1 at PINB4_bit; sbit CF_CE1 at PORTB3_bit; sbit CF_A2 at PORTB2_bit; sbit CF_A1 at PORTB1_bit; sbit CF_A0 at PORTB0_bit; char CF_Data_Port_direction at DDRD; sbit CF_RDY_direction at DDB7_bit; sbit CF_WE_direction at DDB6_bit; sbit CF_OE_direction at DDB5_bit; sbit CF_CD1_direction at DDB4_bit; sbit CF_CE1_direction at DDB3_bit; sbit CF_A2_direction at DDB2_bit; sbit CF_A1_direction at DDB1_bit; sbit CF_A0_direction at DDB0_bit; // end of compact flash pinout ... Cf_Init(); // initialize CF

Cf_Detect

Prototype	unsigned short Cf_Detect(void);
Returns	`1` - if CF card was detected `0` - otherwise
Description	Checks for presence of CF card by reading the `chip detect` pin.
Requires	The corresponding MCU ports must be appropriately initialized for CF card. See Cf_Init.
Example	// Wait until CF card is inserted: do asm nop; while (!Cf_Detect());

Cf_Enable

Prototype	void Cf_Enable(void);
Returns	Nothing.
Description	Enables the device. Routine needs to be called only if you have disabled the device by means of the Cf_Disable routine. These two routines in conjunction allow you to free/occupy data line when working with multiple devices.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// enable compact flash Cf_Enable();

Cf_Disable

Prototype	void Cf_Disable(void);
Returns	Nothing.
Description	Routine disables the device and frees the data lines for other devices. To enable the device again, call Cf_Enable. These two routines in conjunction allow you to free/occupy data line when working with multiple devices.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// disable compact flash Cf_Disable();

Cf_Read_Init

Prototype	void Cf_Read_Init(unsigned long address, unsigned short sector_count);
Returns	Nothing.
Description	Initializes CF card for reading. Parameters : `address:` the first sector to be prepared for reading operation. `sector_count:` number of sectors to be prepared for reading operation.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// initialize compact flash for reading from sector 590 Cf_Read_Init(590, 1);

Cf_Read_Byte

Prototype	unsigned short Cf_Read_Byte(void);
Returns	Returns a byte read from Compact Flash sector buffer. Note : Higher byte of the `unsigned` return value is cleared.
Description	Reads one byte from Compact Flash sector buffer location currently pointed to by internal read pointers. These pointers will be autoicremented upon reading.
Requires	The corresponding MCU ports must be appropriately initialized for CF card. CF card must be initialized for reading operation.
Example	// Read a byte from compact flash: char data; ... data = Cf_Read_Byte();

Cf_Write_Init

Prototype	void Cf_Write_Init(unsigned long address, unsigned short sectcnt);
Returns	Nothing.
Description	Initializes CF card for writing. Parameters : `address:` the first sector to be prepared for writing operation. `sectcnt:` number of sectors to be prepared for writing operation.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// initialize compact flash for writing to sector 590 Cf_Write_Init(590, 1);

Cf_Write_Byte

Prototype	void Cf_Write_Byte(unsigned short data_);
Returns	Nothing.
Description	Writes a byte to Compact Flash sector buffer location currently pointed to by writing pointers. These pointers will be autoicremented upon reading. When sector buffer is full, its contents will be transfered to appropriate flash memory sector. Parameters : `data_:` byte to be written.
Requires	The corresponding MCU ports must be appropriately initialized for CF card. CF card must be initialized for writing operation.
Example	char data_ = 0xAA; ... Cf_Write_Byte(data_);

Cf_Read_Sector

Prototype	void Cf_Read_Sector(unsigned long sector_number, unsigned short *buffer);
Returns	Nothing.
Description	Reads one sector (512 bytes). Read data is stored into buffer provided by the `buffer` parameter. Parameters : `sector_number:` sector to be read. `buffer:` data buffer of at least 512 bytes in length.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// read sector 22 unsigned short data[512]; ... Cf_Read_Sector(22, data);

Cf_Write_Sector

Prototype	void Cf_Write_Sector(unsigned long sector_number, unsigned short *buffer);
Returns	Nothing.
Description	Writes 512 bytes of data provided by the `buffer` parameter to one CF sector. Parameters : `sector_number:` sector to be written to. `buffer:` data buffer of 512 bytes in length.
Requires	The corresponding MCU ports must be appropriately initialized for CF card.
Example	// write to sector 22 unsigned short data[512]; ... Cf_Write_Sector(22, data);

Cf_Fat_Init

Prototype	unsigned short Cf_Fat_Init();
Returns	`0` - if CF card was detected and successfully initialized `1` - if FAT16 boot sector was not found `255` - if card was not detected
Description	Initializes CF card, reads CF FAT16 boot sector and extracts necessary data needed by the library.
Requires	Nothing.
Example	// Init the FAT library if (!Cf_Fat_Init()) { // Init the FAT library ... }

Cf_Fat_QuickFormat

Prototype	unsigned char Cf_Fat_QuickFormat(char *cf_fat_label);
Returns	`0` - if CF card was detected, successfully formated and initialized `1` - if FAT16 format was unseccessful `255` - if card was not detected
Description	Formats to FAT16 and initializes CF card. Parameters : `cf_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, the volume will not be labeled. Note : This routine can be used instead or in conjunction with Cf_Fat_Init routine. If CF card already contains a valid boot sector, it will remain unchanged (except volume label field) and only FAT and ROOT tables will be erased. Also, the new volume label will be set.
Requires	Nothing.
Example	//--- format and initialize the FAT library - if (!Cf_Fat_QuickFormat(&cf_fat_label)) { ... }

Cf_Fat_Assign

Prototype unsigned short Cf_Fat_Assign(char *filename, char file_cre_attr);

Returns

0 if file does not exist and no new file is created.
1 if file already exists or file does not exist but a new file is created.

Description

Assigns file for file operations (read, write, delete...). All subsequent file operations will be applied over the assigned file.
Parameters :

filename: name of the file that should be assigned for file operations. The 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 the 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_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 the 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.

Requires CF card and CF library must be initialized for file operations.

Example

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

Cf_Fat_Reset

Prototype	void Cf_Fat_Reset(unsigned long *size);
Returns	Nothing.
Description	Opens currently assigned file for reading. Parameters : `size:` buffer to store file size to. After file has been open for reading its size is returned through this parameter.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	unsigned long size; ... Cf_Fat_Reset(size);

Cf_Fat_Read

Prototype	void Cf_Fat_Read(unsigned short *bdata);
Returns	Nothing.
Description	Reads a byte from currently assigned file opened for reading. Upon function execution file pointers will be set to the next character in the file. Parameters : `bdata:` buffer to store read byte to. Upon this function execution read byte is returned through this parameter.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned. File must be open for reading.
Example	char character; ... Cf_Fat_Read(&character);

Cf_Fat_Rewrite

Prototype	void Cf_Fat_Rewrite();
Returns	Nothing.
Description	Opens currently assigned file for writing. If the file is not empty its content will be erased.
Requires	CF card and CF library must be initialized for file operations. The file must be previously assigned.
Example	// open file for writing Cf_Fat_Rewrite();

Cf_Fat_Append

Prototype	void Cf_Fat_Append();
Returns	Nothing.
Description	Opens currently assigned file for appending. Upon this function execution file pointers will be positioned after the last byte in the file, so any subsequent file writing operation will start from there.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	// open file for appending Cf_Fat_Append();

Cf_Fat_Delete

Prototype	void Cf_Fat_Delete();
Returns	Nothing.
Description	Deletes currently assigned file from CF card.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	// delete current file Cf_Fat_Delete();

Cf_Fat_Write

Prototype	void Cf_Fat_Write(char fdata, unsigned* data_len);
Returns	Nothing.
Description	Writes requested number of bytes to currently assigned file opened for writing. Parameters : `fdata:` data to be written. `data_len:` number of bytes to be written.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned. File must be open for writing.
Example	char file_contents[42]; ... Cf_Fat_Write(file_contents, 42); // write data to the assigned file

Cf_Fat_Set_File_Date

Prototype	void Cf_Fat_Set_File_Date(unsigned int year, unsigned short month, unsigned short day, unsigned short hours, unsigned short mins, unsigned short seconds);
Returns	Nothing.
Description	Sets the date/time stamp. Any subsequent file writing operation will write this stamp to currently assigned file's time/date attributs. Parameters : `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
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned. File must be open for writing.
Example	Cf_Fat_Set_File_Date(2005,9,30,17,41,0);

Cf_Fat_Get_File_Date

Prototype	void Cf_Fat_Get_File_Date(unsigned int year, unsigned short* month, unsigned short* day, unsigned short* hours, unsigned short* *mins);
Returns	Nothing.
Description	Reads time/date attributes of currently assigned file. Parameters : `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.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	unsigned year; char month, day, hours, mins; ... Cf_Fat_Get_File_Date(&year, &month, &day, &hours, &mins);

Cf_Fat_Get_File_Date_Modified

Prototype	void Cf_Fat_Get_File_Date_Modified(unsigned int year, unsigned short* month, unsigned short* day, unsigned short* hours, unsigned short* *mins);
Returns	Nothing.
Description	Retrieves the last modification date/time of the currently assigned file. Parameters : `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.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	unsigned year; char month, day, hours, mins; ... Cf_Fat_Get_File_Date_Modified(&year, &month, &day, &hours, &mins);

Cf_Fat_Get_File_Size

Prototype	unsigned long Cf_Fat_Get_File_Size();
Returns	Size of the currently assigned file in bytes.
Description	This function reads size of currently assigned file in bytes.
Requires	CF card and CF library must be initialized for file operations. File must be previously assigned.
Example	unsigned long my_file_size; ... my_file_size = Cf_Fat_Get_File_Size();

Cf_Fat_Get_Swap_File

Prototype unsigned long Cf_Fat_Get_Swap_File(unsigned long sectors_cnt, char *filename, char file_attr);

Returns

Number of the start sector for the newly created swap file, if there was enough free space on CF card to create file of required size.
0 - otherwise.

Description

This function is used to create a swap file of predefined name and size on the CF media. If a file with specified name already exists on the media, search for consecutive sectors will ignore sectors occupied by this file. Therefore, it is recommended to erase such file if it exists before calling this function. If it is not erased and there is still enough space for a new swap file, this function will delete it after allocating new memory space for a new swap file.
The purpose of the swap file is to make reading and writing to CF media as fast as possible, by using the Cf_Read_Sector() and Cf_Write_Sector() functions directly, without potentially damaging the FAT system. Swap file can be considered as a "window" on the media where the user can freely write/read data. It's main purpose in the mikroC's library is to be used for fast data acquisition; when the time-critical acquisition has finished, the data can be re-written into a "normal" file, and formatted in the most suitable way.
Parameters:

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. The 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 the 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.

Requires CF card and CF library must be initialized for file operations.

Example

//-------------- Try to create a swap file with archive atribute, whose size will be at least 1000 sectors.
//               If it succeeds, it sends the No. of start sector over UART
unsigned long size;
...
size = Cf_Fat_Get_Swap_File(1000, "mikroE.txt", 0x20);
if (size) {
  UART1_Write(0xAA);
  UART1_Write(Lo(size));
  UART1_Write(Hi(size));
  UART1_Write(Higher(size));
  UART1_Write(Highest(size));
  UART1_Write(0xAA);
}

Library Example

This example consists of several blocks that demonstrate various aspects ofusage of the Cf_Fat16 library. These are:

Creation of new file and writing down to it;
Opening existing file and re-writing it (writing from start-of-file);
Opening existing file and appending data to it (writing from end-of-file);
Opening a file and reading data from it (sending it to USART terminal);
Creating and modifying several files at once;
Reading file contents;
Deleting file(s);
Creating the swap file (see Help for details);

Code Sample

// set compact flash pinout
char Cf_Data_Port at PORTD;
char Cf_Data_Port_Direction at DDRD;

sbit CF_RDY at PINB7_bit;
sbit CF_WE  at PORTB6_bit;
sbit CF_OE  at PORTB5_bit;
sbit CF_CD1 at PINB4_bit;
sbit CF_CE1 at PORTB3_bit;
sbit CF_A2  at PORTB2_bit;
sbit CF_A1  at PORTB1_bit;
sbit CF_A0  at PORTB0_bit;

sbit CF_RDY_direction at DDB7_bit;
sbit CF_WE_direction  at DDB6_bit;
sbit CF_OE_direction  at DDB5_bit;
sbit CF_CD1_direction at DDB4_bit;
sbit CF_CE1_direction at DDB3_bit;
sbit CF_A2_direction  at DDB2_bit;
sbit CF_A1_direction  at DDB1_bit;
sbit CF_A0_direction  at DDB0_bit;
// end of cf pinout

const LINE_LEN = 39;
char err_txt[20]       = "FAT16 not found";
char file_contents[LINE_LEN] = "XX CF FAT16 library by Anton Rieckertn";
char           filename[14] = "MIKRO00x.TXT";          // File names
unsigned short loop, loop2;
unsigned long  i, size;
char           Buffer[512];

// UART1 write text and new line (carriage return + line feed)
void UART1_Write_Line(char *uart_text) {
  UART1_Write_Text(uart_text);
  UART1_Write(13);
  UART1_Write(10);
}

// Creates new file and writes some data to it
void M_Create_New_File() {
  filename[7] = 'A';
  Cf_Fat_Set_File_Date(2005,6,21,10,35,0); // Set file date & time info
  Cf_Fat_Assign(&filename, 0xA0);      // Find existing file or create a new one
  Cf_Fat_Rewrite();                    // To clear file and start with new data
  for(loop = 1; loop <= 99; loop++) {
    UART1_Write('.');
    file_contents[0] = loop / 10 + 48;
    file_contents[1] = loop % 10 + 48;
    Cf_Fat_Write(file_contents, LINE_LEN-1);   // write data to the assigned file
  }
}

// Creates many new files and writes data to them
void M_Create_Multiple_Files() {
  for(loop2 = 'B'; loop2 <= 'Z'; loop2++) {
    UART1_Write(loop2);                  // signal the progress
    filename[7] = loop2;                 // set filename
    Cf_Fat_Set_File_Date(2005,6,21,10,35,0); // Set file date & time info
    Cf_Fat_Assign(&filename, 0xA0);      // find existing file or create a new one
    Cf_Fat_Rewrite();                    // To clear file and start with new data
    for(loop = 1; loop <= 44; loop++) {
      file_contents[0] = loop / 10 + 48;
      file_contents[1] = loop % 10 + 48;
      Cf_Fat_Write(file_contents, LINE_LEN-1);   // write data to the assigned file
    }
  }
}

// Opens an existing file and rewrites it
void M_Open_File_Rewrite() {
  filename[7] = 'C';
  Cf_Fat_Assign(&filename, 0);
  Cf_Fat_Rewrite();
  for(loop = 1; loop <= 55; loop++) {
    file_contents[0] = loop / 10 + 65;
    file_contents[1] = loop % 10 + 65;
    Cf_Fat_Write(file_contents, LINE_LEN-1);     // write data to the assigned file
  }
}

// Opens an existing file and appends data to it
//               (and alters the date/time stamp)
void M_Open_File_Append() {
   filename[7] = 'B';
   Cf_Fat_Assign(&filename, 0);
   Cf_Fat_Set_File_Date(2009, 1, 23, 17, 22, 0);
   Cf_Fat_Append();                                    // Prepare file for append
   Cf_Fat_Write(" for mikroElektronika 2005n", 27);   // Write data to assigned file
}

// Opens an existing file, reads data from it and puts it to UART
void M_Open_File_Read() {
  char character;
  
  filename[7] = 'B';
  Cf_Fat_Assign(&filename, 0);
  Cf_Fat_Reset(&size);             // To read file, procedure returns size of file
  for (i = 1; i <= size; i++) {
    Cf_Fat_Read(&character);
    UART1_Write(character);        // Write data to UART
  }
}

// Deletes a file. If file doesn't exist, it will first be created
// and then deleted.
void M_Delete_File() {
  filename[7] = 'F';
  Cf_Fat_Assign(filename, 0);
  Cf_Fat_Delete();
}

// Tests whether file exists, and if so sends its creation date
// and file size via UART
void M_Test_File_Exist() {
  unsigned long  fsize;
  unsigned int   year;
  unsigned short month, day, hour, minute;
  unsigned char  outstr[12];

  filename[7] = 'B';       //uncomment this line to search for file that DOES exists
//  filename[7] = 'F';       //uncomment this line to search for file that DOES NOT exist
  if (Cf_Fat_Assign(filename, 0)) {
    //--- file has been found - get its date
    Cf_Fat_Get_File_Date(&year, &month, &day, &hour, &minute);
    UART1_Write_Text(" created: ");
    WordToStr(year, outstr);
    UART1_Write_Text(outstr);
    ByteToStr(month, outstr);
    UART1_Write_Text(outstr);
    WordToStr(day, outstr);
    UART1_Write_Text(outstr);
    WordToStr(hour, outstr);
    UART1_Write_Text(outstr);
    WordToStr(minute, outstr);
    UART1_Write_Text(outstr);
    
    //--- file has been found - get its modified date
    Cf_Fat_Get_File_Date_Modified(&year, &month, &day, &hour, &minute);
    UART1_Write_Text(" modified: ");
    WordToStr(year, outstr);
    UART1_Write_Text(outstr);
    ByteToStr(month, outstr);
    UART1_Write_Text(outstr);
    WordToStr(day, outstr);
    UART1_Write_Text(outstr);
    WordToStr(hour, outstr);
    UART1_Write_Text(outstr);
    WordToStr(minute, outstr);
    UART1_Write_Text(outstr);
    
    //--- get file size
    fsize = Cf_Fat_Get_File_Size();
    LongToStr((signed long)fsize, outstr);
    UART1_Write_Line(outstr);
  }
  else {
    //--- file was not found - signal it
    UART1_Write(0x55);
    Delay_ms(1000);
    UART1_Write(0x55);
  }
}


// Tries to create a swap file, whose size will be at least 100
// sectors (see Help for details)
void M_Create_Swap_File() {
  unsigned int i;

  for(i=0; i<512; i++)
    Buffer[i] = i;

  size = Cf_Fat_Get_Swap_File(5000, "mikroE.txt", 0x20);   // see help on this function for details

  if (size) {
    LongToStr((signed long)size, err_txt);
    UART1_Write_Line(err_txt);

    for(i=0; i<5000; i++) {
      Cf_Write_Sector(size++, Buffer);
      UART1_Write('.');
    }
  }
}

// Main. Uncomment the function(s) to test the desired operation(s)
void main() {
  
  // Initialize UART1 module
  UART1_Init(19200);
  Delay_ms(10);

  UART1_Write_Line("MCU-Started"); // MCU present report

  // use fat16 quick format instead of init routine if a formatting is needed
  if (Cf_Fat_Init() == 0) {
    Delay_ms(2000);                // wait for a while until the card is stabilized
                                   //   period depends on used CF card
    //--- Test start
    UART1_Write_Line("Test Start.");
    //--- Test routines. Uncomment them one-by-one to test certain features
    M_Create_New_File();
    M_Create_Multiple_Files();
    M_Open_File_Rewrite();
    M_Open_File_Append();
    M_Open_File_Read();
    M_Delete_File();
    M_Test_File_Exist();
    M_Create_Swap_File();
    UART1_Write_Line("Test End.");
  }
  else {
    UART1_Write_Line(err_txt); // Note: Cf_Fat_Init tries to initialize a card more than once.
                               //       If card is not present, initialization may last longer (depending on clock speed)
  }
}