Mikroelektronika MIKROE-350 数据表
Cf_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 Cf_Fat_Get_Swap_File(dim sectors_cnt as longint, dim
byref filename as string[11], dim file_attr as byte) as longword
byref filename as string[11], dim file_attr as byte) as longword
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 rec-
ommended 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.
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 rec-
ommended 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. The swap file can be con-
sidered as a "window" on the media where the user can freely write/read data.
Its main purpose in the mikroBasic's library is to be used for fast data acquisi-
tion; 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 possible, by using the Cf_Read_Sector() and Cf_Write_Sector() functions
directly, without potentially damaging the FAT system. The swap file can be con-
sidered as a "window" on the media where the user can freely write/read data.
Its main purpose in the mikroBasic's library is to be used for fast data acquisi-
tion; 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 the 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 not
have to take care of that. The file name and extension are case insensitive.
The library will convert them to the 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.
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: