CARD_ReadEeprom

# CARD_ReadEepromAsync

## C Specification

  `#include <nitro/card.h>`
  `static inline void CARD_ReadEepromAsync( u32 src, void *dst, u32 len, MIDmaCallback callback, void *arg);`

## Arguments

src | Transfer source EEPROM address.
dst | Transfer destination memory address
len | Byte length of data being read
callback | Callback function for when the process completes. If the callback is not necessary, specify NULL. This callback is called from inside the interrupt handler.
arg | Argument passed to the callback function when the process completes. If NULL has been specified for the callback, this value is simply ignored.

## Return Values

None.

## Description

This function reads data asynchronously from an EEPROM device. This function immediately returns control. In order to use this function, you must first lock the access bus with the `CARD_LockBackup` function.
To wait for the process to end, use the `CARD_WaitBackupAsync` function. To determine the result of the process, call the `CARD_GetResultCode` function after the process has ended.
This function communicates with the ARM7 processor internally via PXI.
The process will not end if PXI interrupts are not enabled.

## Internal Operation

This function executes an asynchronous process using an internal thread. To learn more about this internal thread, see the explanation for the `CARD_GetThreadPriority` function.

## See Also

`CARD_IsBackupEeprom`, `CARD_WaitBackupAsync`, `CARD_GetResultCode`, `CARD_ReadEeprom`, `CARD_WriteEeprom`, `CARD_VerifyEeprom`, `CARD_WriteAndVerifyEeprom`, `CARD_GetThreadPriority`

## Revision History

06/01/2005 Added a statement indicating that callback is called from interrupt handler.
12/09/2004 Changed "IO processor" to "ARM7 processor".
11/02/2004 Revised links.
08/18/2004 Added description of PXI interrupts.
07/28/2004 Initial version.