Дополнительные команды AVR-DOS
Список команд AVR-DOS — список функций библиотеки AVR-DOS.
Диск/Директория
InitFileSystem
Читает Master boot record и partition boot record (Sector) диска(флэш-карты) и инициализирует файловую систему.
Эта функция должна быть вызвана перед любым другим использованием системы!
bErrorCode = InitFileSystem (bPartitionNumber)
| bErrorCode(Byte) | Код ошибки, возвращает 0 если система успешно запущена. |
| bPartitionNumber(Byte) | Partitionnumber on the Flashcard Drive (normally 1, but use 0 on mediums without Master boot record) |
Пример вызова:
<source lang="vb"> Dim bErrorCode as Byte bErrorCode = InitFileSystem(1) If bErrorCode > 0 then Print "Error: " ; bErrorCode Else Print "Filesystem successfully initialized" End If </source>
DiskSize
Возвращает размер диска.
lSize = DiskSize ()
| lSize(Long) | Объем диска в КБайтах |
Пример вызова:
<source lang="vb"> Dim Gbtemp1 As Byte ' scratch byte Gbtemp1 = Initfilesystem(1) ' we must init the filesystem once If Gbtemp1 > 0 Then Print #1 , "Error " ; Gbtemp1 Else Print #1 , " OK" Print "Disksize : " ; Disksize() ' show disk size in Kbytes Print "Disk free: " ; Diskfree() ' show free space too End If </source>
DiskFree
Возвращает размер свободного пространства диска.
lFreeSize = DiskFree ()
| lFreeSize(Long) | Размер свободной области в КБайтах |
Пример вызова:
<source lang="vb"> Dim Gbtemp1 As Byte ' scratch byte Gbtemp1 = Initfilesystem(1) ' we must init the filesystem once If Gbtemp1 > 0 Then Print #1 , "Error " ; Gbtemp1 Else Print #1 , " OK" Print "Disksize : " ; Disksize() ' show disk size in Kbytes Print "Disk free: " ; Diskfree() ' show free space too End If </source>
Kill
Удаляет файл с диска. Открытый файл не может быть удален. Специальные символы(WildCards) в имени файла, применение масок не поддерживаются. Код ошибки хранится в глобальной переменной gDOSError[1].
Kill sFileName
| sFileName(String) | Имя файла в текущей директории |
Пример вызова:
<source lang="vb"> 'We can use the KILL statement to delete a file. 'A file mask is not supported Print "Kill (delete) file demo" Kill "test.txt" </source>
Dir
Возвращает имя файла, удовлетворяющее маске.
Первый вызов функции содержит маску. Все последующие вызовы совершаются без маски. Фактически, когда вы хотите получить имя следующего файла в данной директории, удовлетворяющее маске, вы должны вызывать вариант функции без параметров после первого вызова.
sFile = Dir(mask)
sFile = Dir()
| SFile(String) | Имя файла. Строка пуста, если больше нет файлов, удовлетворяющих маске |
| Mask(String) | Файловая маска, удовлетворяющая требованиям обычного DOS, напр. *.TXT. Маска *.* удовлетворяет всем файлам |
Пример вызова:
<source lang="vb"> 'Lets have a look at the file we created Print "Dir function demo" S = Dir( "*.*") 'The first call to the DIR() function must contain a file mask ' The * means everything. ' While Len(s) > 0 ' if there was a file found Print S ; " " ; Filedate() ; " " ; Filetime() ; " " ; Filelen() ' print file , the date the fime was created/changed , the time and the size of the file S = Dir() ' get next Wend </source>
FileLen
Возвращает размер файла.
lSize = FileLen ()
lSize = FileLen (file)
| lSize(Long) | Размер файла в Байтах |
| File(String) | Имя файла в текущей директории. Если не указано, параметром считается последний файл, выбранный с помощью DIR() |
Пример вызова:
<source lang="vb"> Print "File demo" Print Filelen( "josef.img") ; " length" ' length of file Print Filetime( "josef.img") ; " time" ' time file was changed Print Filedate( "josef.img") ; " date" ' file date </source>
FileDate
Возвращает дату создания или изменения(?) файла.
sDate = FileDate ()
sDate = FileDate (file)
| sDate(String) | Дата создания или изменения(?) файла |
| File(String) | Имя файла в текущей директории. Если не указано, параметром считается последний файл, выбранный с помощью DIR() |
Пример вызова:
<source lang="vb"> Print "File demo" Print Filelen( "josef.img") ; " length" ' length of file Print Filetime( "josef.img") ; " time" ' time file was changed Print Filedate( "josef.img") ; " date" ' file date </source>
FileTime
Возвращает время создания или изменения(?) файла.
sTime = FileTime ()
sTime = FileTime (file)
| sTime(String) | Время создания или изменения(?) файла |
| File(String) | Имя файла в текущей директории. Если не указано, параметром считается последний файл, выбранный с помощью DIR() |
Пример вызова:
<source lang="vb"> Print "File demo" Print Filelen( "josef.img") ; " length" ' length of file Print Filetime( "josef.img") ; " time" ' time file was changed Print Filedate( "josef.img") ; " date" ' file date </source>
FileDateTime
Возвращает дату и время создания или изменения(?) файла.
Var = FileDateTime ()
Var = FileDateTime (file)
| Var(String) | Время создания или изменения(?) файла |
| File(String) | When the target variable is a string, it must be dimensioned with a length of at least 17 bytes. |
| File(Byte array) | When the target variable is a byte array, the array size must be at least 6 bytes. |
| File(Numeric) | When you use a numeric variable, the internal file date and time format will be used. |
Пример вызова:
<source lang="vb"> ' Read and print Directory and show Filename, Date, Time, Size ' for all files matching pStr1 and create/update younger than pDays Sub Directorylist(pstr1 As String , Byval Pdays As Word) Local lFileName as String * 12 ' hold file name for print Local lwCounter as Word , lFileSizeSum as Long ' for summary Local lwNow as Word , lwDays as Word Local lSec as Byte , lMin as Byte , lHour as byte , lDay as byte , lMonth as byte , lYear as byte print "Listing of all Files matching " ; pStr1 ; " and create/last update date within " ; pdays ; " days" lwNow = SysDay() lwCounter = 0 : lFileSizeSum = 0 lFileName = Dir(pStr1) While lFileName <> "" lsec = FileDateTime() lwDays = lwNow - SysDay(lDay) ' Days between Now and last File Update; uses lDay, lMonth, lYear if lwDays <= pDays then ' days smaller than desired with parameter print lFileName ; FileDate() ; " " ; FileTime() ; " " ; filelen() incr lwCounter : lFileSizeSum = FileLen() + lFileSizeSum end if lFileName = Dir() WEnd print lwCounter ; " File(s) found with " ; lFileSizeSum ; " Byte(s)" End Sub </source>
GetAttr
Возвращает атрибуты файла.
bAttr = FileDate ()
bAttr = FileDate (file)
| bAttr(Byte) | Атрибуты файла, совместимые с DOS-форматом. Байт расшифровывается как 00ADVSHR, где биты 5-0:
A - Архивный |
| File(String) | Имя файла в текущей директории. Если не указано, параметром считается последний файл, выбранный с помощью DIR() |
Пример вызова:
<source lang="vb"> Print "File demo" Print Filelen( "josef.img") ; " length" ' length of file Print Filetime( "josef.img") ; " time" ' time file was changed Print Filedate( "josef.img") ; " date" ' file date Print Bin(GetAttr(“Josef.img”)) ; “Attributes” ‘ DOS Attributes </source>
Name
Переименовывает файл в текущей директории. Файл с новым именем не должен существовать в текущей директории, иначе команда вернет ошибку. Код ошибки можно посмотреть в глобальной переменной gbDOSError[1].
Name <strOldFilename> As <strNewFileName>
| strOldFileName(String) | Старое имя файла |
| strNewFileName(String) | Новое имя файла |
Пример вызова:
<source lang="vb"> Dim strOldFileName as String * 12 Dim strNewFileName as String * 12
strOldFileName = "Data.txt" strNewFileName = "Data.bak" Name strOldFilename As strNewFileName </source>
ChDir
Изменяет текущую директорию.
Функции Kill, Dir, ChDir, MkDir, RmDir, Name, FileLen, FileDateTime, FileDate, FileTime, GetAttr, Open, BLoad и BSave работают только в текущей директории. Обращаться к файлу с помощью составного пути запрещается!
ChDIR (strDirectoryName)
| strDirectoryName(String) | Путь к новой директории, длина не более 8 символов. Допускаются следующие спецсимволы: "." - на директорию выше |
Пример вызова:
<source lang="vb"> Dim strDirectory as String * 12
ChDir "SubDir" ' or strDirectory = "SubDir" ChDir strDirectory
' Change to next higher directory ChDir "." ' Change to Root Directory strDirectory = "\" ChDir strDirectory </source>
MkDir
Создает каталог в текущей директории.
MkDIR (strDirectoryName)
| strDirectoryName(String) | Имя новой директории, не более 8 символов |
Пример вызова:
<source lang="vb"> Dim strDirectory as String * 12 MkDir "NewDir" ' or strDirectory = "NewDir" MkDir strDirectory </source>
RmDir
Удаляет каталог в текущей директории.
RmDIR (strDirectoryName)
| strDirectoryName(String) | Имя каталога для удаления, не более 8 символов |
Пример вызова:
<source lang="vb"> Dim strDirectory as String * 12 MkDir "NewDir" ' or strDirectory = "NewDir" MkDir strDirectory </source>
Файлы
FreeFile
Возвращает свободный файловый идентификатор (filenumber).
bFileNumber = FreeFile()
| bFileNumber(Byte) | Свободный файловый идентификатор из множества 128..255, который может использоваться для открытия новых файлов. Используйте числа 1..127 для пользовательских идентификаторов, чтобы избежать конфликтов имен при использованиии функций файловой системы. |
Пример вызова:
<source lang="vb"> Ff = Freefile() ' get file handle Open "test.txt" For Input As #ff ' we can use a constant for the file too Print Lof(#ff) ; " length of file" Print Fileattr(#ff) ; " file mode" ' should be 1 for input Do Line Input #ff , S ' read a line ' line input is used to read a line of text from a file Print S ' print on terminal emulator Loop Until Eof(ff) <> 0 'The EOF() function returns a non-zero number when the end of the file is reached 'This way we know that there is no more data we can read Close #ff </source>
Open
Открывает устройство.
OPEN "device" for MODE As #channel
OPEN file FOR MODE as #channel
| Device | The default device is COM1 and you don't need to open a channel to use INPUT/OUTPUT on this device.
With the implementation of the software UART, the compiler must know to which pin/device you will send/receive the data. So that is why the OPEN statement must be used. It tells the compiler about the pin you use for the serial input or output and the baud rate you want to use. COMB.0:9600,8,N,2 will use PORT B.0 at 9600 baud with 2 stopbits. The format for COM1 and COM2 is : COM1: or COM2: There is no speed/baud rate parameter since the default baud rate will be used that is specified with $BAUD or $BAUD1 The format for the software UART is: COMpin:speed,8,N,stopbits[,INVERTED] Where pin is the name of the PORT-pin. Speed must be specified and stop bits can be 1 or 2. 7 bit data or 8 bit data may be used. For parity N, O or E can be used. An optional parameter ,INVERTED can be specified to use inverted RS-232. Open "COMD.1:9600,8,N,1,INVERTED" For Output As #1 , will use pin PORTD.1 for output with 9600 baud, 1 stop bit and with inverted RS-232. For the AVR-DOS filesystem, Device can also be a string or filename constant like "readme.txt" or sFileName |
| Mode | You can use BINARY or RANDOM for COM1 and COM2, but for the software UART pins, you must specify INPUT or OUTPUT
For the AVR-DOS filesystem, MODE may be INPUT, OUTPUT, APPEND or BINARY |
| Channel | The number of the channel to open. Must be a positive constant >0
For the AVR-DOS filesystem, the channel may be a positive constant or a numeric variable. Note that the AVD-DOS filesystem uses real filehandles. The software UART does not use real file handles. |
Пример вызова:
<source lang="vb"> OPEN "com1:" for binary as #1 Call test End Sub test Print #1, "test" End Sub Close #1 </source>
Close
Освобождает открытое устройство. The statements that support the device are PRINT , INPUT and INPUTHEX , INKEY, WAITKEY. Every opened device must be closed using the CLOSE #channel statement. Of course, you must use the same channel number. The best place for the CLOSE statement is at the end of your program. The INPUT statement in combination with the software UART, will not echo characters back because there is no default associated pin for this. For the AVR-DOS filesystem, you may place the CLOSE at any place in your program. This because the filesystem supports real file handles.
OPEN "device" for MODE As #channel
...
CLOSE #channel
| Device | The default device is COM1 and you don't need to open a channel to use INPUT/OUTPUT on this device.
With the implementation of the software UART, the compiler must know to which pin/device you will send/receive the data. So that is why the OPEN statement must be used. It tells the compiler about the pin you use for the serial input or output and the baud rate you want to use. COMB.0:9600,8,N,2 will use PORT B.0 at 9600 baud with 2 stop bits. The format for COM1 is : COM1: Some chips have 2 UARTS. You can use COM2: to open the second HW UART. The format for the software UART is: COMpin:speed,8,N,stop bits[,INVERTED] Where pin is the name of the PORT-pin. Speed must be specified and stop bits can be 1 or 2. An optional parameter ,INVERTED can be specified to use inverted RS-232. Open "COMD.1:9600,8,N,1,INVERTED" For Output As #1 , will use pin PORTD.1 for output with 9600 baud, 1 stop bit and with inverted RS-232 |
| MODE | You can use BINARY or RANDOM for COM1 and COM2, but for the software UART pins, you must specify INPUT or OUTPUT |
| Channel | The number of the channel to open. Must be a positive constant >0 |
Пример вызова:
<source lang="vb"> $crystal = 10000000 'change to the value of the XTAL you have installed
Dim B As Byte
'Optional you can fine tune the calculated bit delay 'Why would you want to do that? 'Because chips that have an internal oscillator may not 'run at the speed specified. This depends on the voltage, temp etc. 'You can either change $CRYSTAL or you can use 'BAUD #1,9610
'In this example file we use the DT006 from www.simmstick.com 'This allows easy testing with the existing serial port 'The MAX232 is fitted for this example. 'Because we use the hardware UART pins we MAY NOT use the hardware UART 'The hardware UART is used when you use PRINT, INPUT or other related statements 'We will use the software UART. Waitms 100
'open channel for output Open "comd.1:19200,8,n,1" For Output As #1 Print #1 , "serial output"
'Now open a pin for input
Open "comd.0:19200,8,n,1" For Input As #2
'since there is no relation between the input and output pin
'there is NO ECHO while keys are typed
Print #1 , "Number"
'get a number
Input #2 , B
'print the number
Print #1 , B
'now loop until ESC is pressed 'With INKEY() we can check if there is data available 'To use it with the software UART you must provide the channel Do 'store in byte B = Inkey(#2) 'when the value > 0 we got something If B > 0 Then Print #1 , Chr(b) 'print the character End If Loop Until B = 27
Close #2
Close #1
'OPTIONAL you may use the HARDWARE UART
'The software UART will not work on the hardware UART pins
'so you must choose other pins
'use normal hardware UART for printing
'Print B
'When you dont want to use a level inverter such as the MAX-232
'You can specify ,INVERTED :
'Open "comd.0:300,8,n,1,inverted" For Input As #2
'Now the logic is inverted and there is no need for a level converter
'But the distance of the wires must be shorter with this
End
</source>
Flush
Write current buffer of File to Card and updates Directory. This function writes all information of an open file, which is not saved yet to the Disk. Normally the Card is updated, if a file will be closed or changed to another sector. When no filenumber is specified, all open files will be flushed.
Flush #bFileNumber
Flush
| BFileNumber(Byte) | Filenumber, which identifies an opened file such as #1 or #ff |
Пример вызова:
<source lang="vb"> $include "startup.inc"
'open the file in BINARY mode Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Lof(#2) ; " length of file" Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string
Flush #2 ' flush to disk Close #2 </source>
Процедура выводит параметр в RS-232 порт, также может записать строку в файл.
Используйте разделитель (;) для вывода более одного параметра. Если вы заканчиваете вывод разделителем, новая строка после вывода не создается. Процедура может использоваться только если микроконтроллер имеет железную реализацию RS-232 «(The PRINT routine can be used when you have a RS-232 interface on your uP)». RS-232 интерфейс может быть подключен к COM-порту компьютера через преобразователь уровней TTL(подробнее), в этом случае вы можете использовать встроенный терминал, чтобы следить за сообщениями устройства. AVR-DOS также поддерживает PRINT процедуру, но на диск могут быть записаны только строки «(The AVR-DOS filesystem also supports PRINT. But in that case, only strings can be written to disk)».
PRINT var ; " constant"
| Var(...) | Переменные или константы для вывода |
Пример вызова:
<source lang="vb"> Dim A As Byte , B1 As Byte , C As Integer , S As String * 4 A = 1 Print "print variable a " ; A Print 'new line Print "Text to print." 'constant to print
B1 = 10
Print Hex(b1) 'print in hexa notation
C = &HA000 'assign value to c%
Print Hex(c) 'print in hex notation
Print C 'print in decimal notation
C = -32000 Print C Print Hex(c) Rem Note That Integers Range From -32767 To 32768 End </source>
Write
Процедура записывает параметры в открытый файловый поток.
Для записи переменной используется ASCII представление, т.е. файл будет выглядеть как текст. Вы можете записывать переменные в бинарном представлении используя команду PUT, в этом случае файлы не будут содержать непечатных символов «(забыл как называется, unreadable characters)». Строки обособляются символом ("). Множественные переменные разделяются запятыми, например:
<source lang="vb"> Dim S as String * 10 , W as Word
S="hello" : W = 100
OPEN "test.txt" For OUTPUT as #1
WRITE #1, S , W
CLOSE #1</source>
Файл будет выглядеть как: "hello",100. Используйте команду INPUT чтобы прочитать переменные из файла.
Write #ch , data [,data1]
| Ch(Byte) | Идентификационный номер файлового потока, может быть переменной или константой. |
| Data , data1 | Переменные или константы для вывода |
Пример вызова:
<source lang="vb"> Dim S As string * 10 , W As Word ,L As Long S = "write" Open "write.dmo" For Output As #2 Write #2 , S , W , L ' write is also supported Close #2 Open "write.dmo" For Input As #2 Input #2 , S , W , L ' write is also supported Close #2 Print S ; " " ; W ; " " ; L </source>
Input
Read a Line from an opened File. Only valid for files opened in mode INPUT. Line INPUT works only with strings. It is great for working on text files.
LineInput #bFileNumber, sLineText
| BfileNumber(Byte) | Filenumber, which identifies an opened file |
| SlineText(String) | A string, which is assigned with the next line from the file |
Пример вызова:
<source lang="vb"> 'Ok we want to check if the file contains the written lines Ff = Freefile() ' get file handle Open "test.txt" For Input As #ff ' we can use a constant for the file too Print Lof(#ff) ; " length of file" Print Fileattr(#ff) ; " file mode" ' should be 1 for input Do Line Input #ff , S ' read a line ' line input is used to read a line of text from a file Print S ' print on terminal emulator Loop Until Eof(ff) <> 0 'The EOF() function returns a non-zero number when the end of the file is reached 'This way we know that there is no more data we can read Close #ff </source>
Line Input
Read a Line from an opened File. Only valid for files opened in mode INPUT. Line INPUT works only with strings. It is great for working on text files.
LineInput #bFileNumber, sLineText
| BfileNumber(Byte) | Filenumber, which identifies an opened file |
| SlineText(String) | A string, which is assigned with the next line from the file. |
Пример вызова:
<source lang="vb"> 'Ok we want to check if the file contains the written lines Ff = Freefile() ' get file handle Open "test.txt" For Input As #ff ' we can use a constant for the file too Print Lof(#ff) ; " length of file" Print Fileattr(#ff) ; " file mode" ' should be 1 for input Do Line Input #ff , S ' read a line ' line input is used to read a line of text from a file Print S ' print on terminal emulator Loop Until Eof(ff) <> 0 'The EOF() function returns a non-zero number when the end of the file is reached 'This way we know that there is no more data we can read Close #ff </source>
Get
Reads a byte from the hardware or software UART. Reads data from a file opened in BINARY mode.
GET in combination with the software/hardware UART is provided for compatibility with BASCOM-8051. It reads one byte. GET in combination with the AVR-DOS filesystem is very flexible and versatile. It works on files opened in BINARY mode and you can reads all data types. By default you only need to provide the variable name. When the variable is a byte, 1 byte wil be read. When the variable is a word or integer, 2 bytes will be read. When the variable is a long or single, 4 bytes will be read. When the variable is a string, the number of bytes that will be read is equal to the dimensioned size of the string. DIM S as string * 10 , would read 10 bytes. Note that when you specify the length for a string, the maximum length is 255. The maximum length for a non-string array is 65535. <source lang="vb"> Example : GET #1 , var ,,2 ‘ read 2 bytes, start at current position GET #1, var , PS ‘ start at position stored in long PS GET #1, var , PS, 2 ‘ start at position stored in long PS and read 2 bytes</source>
GET #channel, var
GET #channel, var , [pos] [, length]
| #channel(...) | A channel number, which identifies an opened file. This can be a hard coded constant or a variable |
| Var(...) | The variable or variable array that will be assigned with the data from the file |
| Pos(...) | This is an optional parameter that may be used to specify the postion where the reading must start from. This must be a long variable |
| Length(...) | This is an optional parameter that may be used to specify how many bytes must be read from the file. |
Пример вызова:
<source lang="vb"> 'for the binary file demo we need some variables of different types Dim B As Byte , W As Word , L As Long , Sn As Single , Ltemp As Long Dim Stxt As String * 10 B = 1 : W = 50000 : L = 12345678 : Sn = 123.45 : Stxt = "test"
'open the file in BINARY mode Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Seek(#2) ; " = LOC+1"
Print Lof(#2) ; " length of file" Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string
Flush #2 ' flush to disk Close #2
'now open the file again and write only the single Open "test.bin" For Binary As #2 L = 1 'specify the file position B = Seek(#2 , L) ' reset is the same as using SEEK #2,L Get #2 , B ' get the byte Get #2 , W ' get the word Get #2 , L ' get the long Get #2 , Sn ' get the single Get #2 , Stxt ' get the string Close #2 </source>
Put
Writes a byte to the hardware or software UART. Writes data to a file opened in BINARY mode.
PUT in combination with the software/hardware UART is provided for compatibility with BASCOM-8051. It writes one byte PUT in combination with the AVR-DOS filesystem is very flexible and versatile. It works on files opened in BINARY mode and you can write all data types. By default you only need to provide the variable name. When the variable is a byte, 1 byte wil be written. When the variable is a word or integer, 2 bytes will be written. When the variable is a long or single, 4 bytes will be written. When the variable is a string, the number of bytes that will be written is equal to the dimensioned size of the string. DIM S as string * 10 , would write 10 bytes. Note that when you specify the length for a string, the maximum length is 255. The maximum length for a non-string array is 65535. Example: <source lang="vb"> PUT #1, var PUT #1, var , , 2 ‘ write 2 bytes at default position PUT #1, var ,PS, 2 ‘ write 2 bytes at location storied in variable PS</source>
PUT #channel, var
PUT #channel, var ,[pos] [,length]
| #channel(...) | A channel number, which identifies an opened file. This can be a hard coded constant or a variable. |
| Var(...) | The variable or variable array that will be written to the file |
| Pos(...) | This is an optional parameter that may be used to specify the postion where the data must be written to. This must be a long variable. |
| Length(...) | This is an optional parameter that may be used to specify how many bytes must be written to the file. |
Пример вызова:
<source lang="vb"> 'for the binary file demo we need some variables of different types Dim B As Byte , W As Word , L As Long , Sn As Single , Ltemp As Long Dim Stxt As String * 10 B = 1 : W = 50000 : L = 12345678 : Sn = 123.45 : Stxt = "test"
'open the file in BINARY mode Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Seek(#2) ; " = LOC+1"
Print Lof(#2) ; " length of file" Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string
Flush #2 ' flush to disk Close #2
'now open the file again and write only the single Open "test.bin" For Binary As #2 L = 1 'specify the file position B = Seek(#2 , L) ' reset is the same as using SEEK #2,L Get #2 , B ' get the byte Get #2 , W ' get the word Get #2 , L ' get the long Get #2 , Sn ' get the single Get #2 , Stxt ' get the string Close #2 </source>
Seek
Function: Returns the position of the next Byte to be read or written. Statement: Sets the position of the next Byte to be read or written.
This function returns the position of the next Byte to be read or written. If an error occures, 0 is returned. Check DOS-Error in variable gbDOSError[1]. The statetement also returns an error in the gbDOSerror variable in the event that an error occurs. You can for example not set the fileposition behinds the filesize. In QB/VB the file is filled with 0 bytes when you set the filepointer behind the size of the file. For embedded systems this does not seem a good idea. Seek and Loc seems to do the same function, but take care : the seek function will return the position of the next read/write, while the Loc function returns the position of the last read/write. You may say that Seek = Loc+1. Difference with QB In QB/VB you can use seek to make the file bigger. When a file is 100 bytes long, setting the filepointer to 200 will increase the file with 0 bytes. By design this is not the case in AVR-DOS.
Function: NextReadWrite = Seek (#bFileNumber)
Statement: Seek #bFileNumber, NewPos)
| bFileNumber(Byte) | Filenumber, which identifies an opened file |
| NextReadWrite(Long) | A Long Variable, which is assigned with the Position of the next Byte to be read or written (1-based) |
| NewPos(Long) | A Long variable that holds the new position the filepointer must be set too. |
Пример вызова:
<source lang="vb"> Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Seek(#2) ; " = LOC+1"
Close #2
'now open the file again and write only the single Open "test.bin" For Binary As #2 Seek #2 , Ltemp ' set the filepointer Sn = 1.23 ' change the single value so we can check it better Put #2 , Sn = 1 'specify the file position Close #2 </source>
Свойства файла
EOF
Returns the End of File Status.
This functions returns information about the End of File Status.
| Return value | Status |
|---|---|
| 0 | NOT EOF |
| 255 | EOF |
In case of error (invalid filenumber) 255 (EOF) is returned too.
bFileEOFStatus = EOF(#bFileNumber)
| bFileEOFStatus(Byte) | A Byte Variable, which issigned with the EOF Status |
| bFileNumber(Byte) | Number of the opened file |
Пример вызова:
<source lang="vb"> Ff = Freefile() ' get file handle Open "test.txt" For Input As #ff ' we can use a constant for the file too Print Lof(#ff) ; " length of file" Print Fileattr(#ff) ; " file mode" ' should be 1 for input Do Line Input #ff , S ' read a line ' line input is used to read a line of text from a file Print S ' print on terminal emulator Loop Until Eof(ff) <> 0 'The EOF() function returns a non-zero number when the end of the file is reached 'This way we know that there is no more data we can read Close #ff </source>
LOC
Returns the position of last read or written Byte of the file.
This function returns the position of the last read or written Byte. If an error occurs, 0 is returned. Check DOS-Error in variable gbDOSError[1]. If the file position pointer is changed with the command SEEK, this function can not be used till the next read/write operation. Difference with QB This function differs from QB. In QB the byte position is divided by 128.
lLastReadWritten = Loc (#bFileNumber)
| bFileNumber(Byte) | Filenumber, which identifies an opened file |
| lLastReadWritten(Long) | Variable, whichsigned with the Position of last read or written Byte (1-based) |
Пример вызова:
<source lang="vb"> 'open the file in BINARY mode Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Lof(#2) ; " length of file" Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string
Flush #2 ' flush to disk Close #2 </source>
LOF
Returns the length of the File in Bytes.
This function returns the length of an opened file. If an error occures, 0 is returned. Check DOS-Error in variable gbDOSError[1].
lFileLength = LOF (#bFileNumber)
| bFileNumber(Byte) | Filenumber, which identifies an opened file |
| LFileLength(Long) | Variable, which issigned with the Length of the file (1-based) |
Пример вызова:
<source lang="vb"> 'open the file in BINARY mode Open "test.biN" For Binary As #2 Put #2 , B ' write a byte Put #2 , W ' write a word Put #2 , L ' write a long Ltemp = Loc(#2) + 1 ' get the position of the next byte Print Ltemp ; " LOC" ' store the location of the file pointer Print Lof(#2) ; " length of file" Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string
Flush #2 ' flush to disk Close #2 </source>
FileAttr
Returns the file open mode.
This functions returns information about the File open mode
bFileAttribut = FileAttr (bFileNumber)
| Return value | Open mode |
|---|---|
| 1 | INPUT |
| 2 | OUTPUT |
| 8 | APPEND |
| 32 | BINARY |
| bFileAttribut(Long) | File open mode, See table |
| bFileNumber(Byte) | Number of the opened file |
Пример вызова:
<source lang="vb"> 'open the file in BINARY mode Open "test.biN" For Binary As #2 Print Fileattr(#2) ; " file mode" ' should be 32 for binary Put #2 , Sn ' write a single Put #2 , Stxt ' write a string Close #2 </source>
Другие
Bload
Writes the Content of a File into SRAM.
This function writes the content of a file to a desired space in SRAM. A free handle is needed for this function.
BLoad sFileName, wSRAMPointer
| sFileName(Long) | Name of the File to be read |
| wSRAMPointer(Word) | Variable, which holds the SRAM Address to which the content of the file should be written |
Пример вызова:
<source lang="vb"> 'now the good old bsave and bload Dim Ar(100) As Byte , I As Byte For I = 1 To 100 Ar(i) = I ' fill the array Next
Wait 2
W = Varptr(ar(1)) Bsave "josef.img" , W , 100 For I = 1 To 100 Ar(i) = 0 ' reset the array Next
Bload "josef.img" , W ' Josef you are amazing !
For I = 1 To 10 Print Ar(i) ; " " ; Next Print </source>
Bsave
Save a range in SRAM to a Fileю
This function writes a range from the SRAM to a file. A free file handle is needed for this function.
BSave sFileName, wSRAMPointer, wLength
| sFileName(Long) | Name of the File to be written |
| wSRAMPointer(Word) | Variable, which holds the SRAM Address, from where SRAM should be written to a File |
| wLength(Word) | Count of Bytes from SRAM, which should be written to the file |
Пример вызова:
<source lang="vb">'now the good old bsave and bload Dim Ar(100) As Byte , I As Byte For I = 1 To 100 Ar(i) = I ' fill the array Next
Wait 2
W = Varptr(ar(1)) Bsave "josef.img" , W , 100 For I = 1 To 100 Ar(i) = 0 ' reset the array Next
Bload "josef.img" , W ' Josef you are amazing !
For I = 1 To 10 Print Ar(i) ; " " ; Next Print </source>
