Техническая Спецификация для Mikroelektronika MIKROE-350
Mmc_Fat_Get_Swap_File
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MIKROELEKTRONIKA
- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD
Libraries
mikroBasic PRO for AVR
CHAPTER 6
Prototype
sub function Mmc_Fat_Get_Swap_File(dim sectors_cnt as longint,
dim byref filename as string[11], dim file_attr as byte) as dword
dim byref filename as string[11], dim file_attr as byte) as dword
Returns
- 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.
Description
This function is used to create a swap file of predefined name and size on the
MMC/SD media. If a file with specified name already exists on the media,
search for consecutive sectors will ignore sectors occupied by this file. There-
fore, it is recommended to erase such file if it already 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.
MMC/SD media. If a file with specified name already exists on the media,
search for consecutive sectors will ignore sectors occupied by this file. There-
fore, it is recommended to erase such file if it already 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 MMC/SD media
as fast as possible, by using the Mmc_Read_Sector() and Mmc_Write_Sector()
functions directly, without potentially damaging the FAT system. The 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 mikroBasic PRO for AVR'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.
as fast as possible, by using the Mmc_Read_Sector() and Mmc_Write_Sector()
functions directly, without potentially damaging the FAT system. The 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 mikroBasic PRO for AVR'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. 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 no
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.
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 no
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 last 3 characters of the string are considered
to be file extension.
with no dot character between file name and extension (i.e. "MIKROELETXT" -
> MIKROELE.TXT). In this case 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: