DriveReadSector

DriveReadSector

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Action

Read a Sector (512 Bytes) from the (Compact Flashcard) Drive

 

 

Syntax

bErrorCode = DRIVEREADSECTOR(wSRAMPointer, lSectorNumber)

 

 

Remarks

bErrorCode

A Byte Variable, which is assigned with the error code of the function

wSRAMPointer

A Word Variable, which contains the SRAM address (pointer) , to which the Sector from the Drive should be written

lSectorNumber

A Long Variable, which give the sector number on the drive be transfer.

 

Reads a Sector (512 Bytes) from the Drive and write it to SRAM starting at the address, to which the content of the variable wSRAMPointer is pointing. The functions returns 0 if no error occurred. For Error code see section Error codes.

 

Note: wSRAMPointer is not the variable, to which the content of the desired drive-sector should be written, it is the Word-Variable/Value which contains the SRAM address of the range, to which 512 Bytes should be written from the Drive. This gives you the flexibility to read and write every SRAM-Range to and from the drive, even it is not declared as variable. If you know the SRAM-Address (from the compiler report) of a buffer you can pass this value directly, otherwise you can get the address with the BASCOM-function VARPTR (see example).

 

 

See also

DriveCheck, DriveReset , DriveInit , DriveGetIdentity , DriveWriteSector

 

 

ASM

Calls

_DriveReadSector

 

Input

Z: SRAM-Address of buffer

*)

X: Address of Long-variable with sectornumber

Output

r25: Errorcode

C-Flag: Set on Error

 

 

 

noticeThis is not the address of wSRAMPointer, it is its content, which is the starting-address of the buffer.

 

 

Partial Example

Dim bError as Byte

Dim aBuffer(512)as Byte' Hold Sector to and from CF-Card

Dim wSRAMPointer as Word' Address-Pointer for write

Dim lSectorNumber as Long' Sector Number

 

' give Address of first Byte of the 512 Byte Buffer to Word-Variable

wSRAMPointer =VarPtr(aBuffer(1))

 

' Set Sectornumber, sector 32 normally holds the Boot record sector of first partition

lSectorNumber = 32

 

' Now read in sector 32 from CF-Card

bError = DriveReadSector( wSRAMPointer , lSectorNumber)

' Now Sector number 32 is in Byte-Array bBuffer