# CARD_EraseFlashSectorAsync

## Syntax

  `#include <nitro/card.h>`
  `SDK_INLINE void CARD_EraseFlashSectorAsync( u32 dst, u32 len, MIDmaCallback callback, void *arg);`

## Arguments

dst | The flash memory address to erase. This must be an integer multiple of the value obtained by the `CARD_GetBackupSectorSize` function. For more about the sector size for each device, see Overview.
len | Number of bytes to erase. This must be an integer multiple of the value obtained by the `CARD_GetBackupSectorSize` function. For more about the sector size for each device, see Overview.
callback | Completion callback function. Specify `NULL` if this is unnecessary. This callback is called from within the interrupt handler.
arg | Arguments to pass to the completion callback function. This is simply ignored if `NULL` was specified for `callback`.

## Return Values

None.

## Description

Deletes data on a FLASH device in sector units and initializes all data in the sector with 0xFF. This function immediately returns control. Use the `CARD_WaitBackupAsync` function to wait for processing to end. To determine the processing result, call the `CARD_GetResultCode` function after processing has ended.

You must use this function in advance to erase the contents of the region specified as the destination for writing with the `CARD_ProgramFlashAsync` function. We cannot guarantee integrity of the data written to a region that has not been erased.For certain kinds of flash devices you can use the `CARD_WriteFlash` function, which has fewer restrictions than these functions.

To use this function, you must first lock the access bus with the `CARD_LockBackup` function.

## Internal Operation

`This function communicates with the ARM7 processor internally via PXI.
The process will not end if PXI interrupts are not enabled.
The function uses an internal thread to execute an asynchronous process. See the description of the `CARD_GetThreadPriority` function for more information on this thread.`

## See Also

`CARD_WaitBackupAsync, CARD_GetResultCode, CARD_IsBackupFlash, CARD_ProgramFlash, CARD_ProgramFlashAsync, CARD_ProgramAndVerifyFlash, CARD_ProgramAndVerifyFlashAsync, CARD_EraseFlashSector, CARD_EraseFlashSectorAsync, CARD_WriteFlashSector, CARD_WriteFlashSectorAsync, CARD_WriteAndVerifyFlashSector, CARD_WriteAndVerifyFlashSectorAsync, CARD_ReadFlash, CARD_WriteFlash, CARD_WriteAndVerifyFlash, CARD_VerifyFlash, CARD_GetThreadPriority`

## Revision History

2007/08/22 Initial version.

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