Diese github page zeigt ein Beispiel Funktion SpiAtmelFlashRead
mit folgenden Syntax benannt:
SPI_Status = SpiAtmelFlashRead(&spi, Address, ByteCount);
Der Code innerhalb der Lesefunktion ist:
/*****************************************************************************/
/**
*
* This function reads data from the Atmel Flash device connected to the SPI
* interface.
*
* @param SpiPtr is a pointer to the SPI driver component to use.
* @param Addr is the address from which the data is to be read from
* the Flash.
* @param ByteCount is the number of bytes to read.
*
* @return XST_SUCCESS if successful else XST_FAILURE.
*
* @note None.
*
******************************************************************************/
int SpiAtmelFlashRead(XSpi *SpiPtr, u32 Address, u16 ByteCount)
{
u16 Index;
/*
* Setup the read command with the specified address and data for the
* Atmel Flash.
*/
WriteBuffer[ATMEL_COMMAND_OFFSET] = ATMEL_COMMAND_READ;
WriteBuffer[ATMEL_ADDRESS_BYTE1_OFFSET] = (u8) (Address >> 16);
WriteBuffer[ATMEL_ADDRESS_BYTE2_OFFSET] = (u8) (Address >> 8);
WriteBuffer[ATMEL_ADDRESS_BYTE3_OFFSET] = (u8) Address;
/*
* Prepare the write buffer. Fill in some dummy data.
*/
for(Index = 4; Index < (ByteCount + ATMEL_READ_WRITE_EXTRA_BYTES);
Index++) {
WriteBuffer[Index] = ATMEL_DUMMYBYTE;
}
/*
* Prepare the Read Buffer. Fill in some initialization data into the
* the buffer.
*/
for(Index = 0; Index < (ByteCount +
ATMEL_READ_WRITE_EXTRA_BYTES); Index++) {
ReadBuffer[Index] = ATMEL_INITBYTE;
}
/*
* Send the read command to the Atmel Flash to read the specified number
* of bytes.
*/
TransferInProgress = TRUE;
XSpi_Transfer(SpiPtr, WriteBuffer, ReadBuffer,
ByteCount + ATMEL_READ_WRITE_EXTRA_BYTES);
/*
* Wait till the Transfer is complete and check if there are any errors
* in the transaction.
*/
while (TransferInProgress);
if(ErrorCount != 0) {
ErrorCount = 0;
return XST_FAILURE;
}
return XST_SUCCESS;
}
Diese github page ein Beispiel Funktion SpiAtmelFlashWrite
namens zeigt mit der folgenden Syntax:
SPI_Status = SpiAtmelFlashWrite(&spi, Address, chunk, ByteCount);
der Code innerhalb der Schreibfunktion ist:
/*****************************************************************************/
/**
*
* This function writes to the Atmel Flash device connected to the SPI interface.
*
* @param SpiPtr is a pointer to the SPI driver component to use.
* @param Address is the address to which the data is written.
* @param ByteCount contains the number of bytes to write.
*
* @return XST_SUCCESS if successful else XST_FAILURE.
*
* @note None.
*
******************************************************************************/
int SpiAtmelFlashWrite(XSpi *SpiPtr, u32 Address, u16 ByteCount)
{
u16 Index;
/*
* Setup the write command with the specified address, and data to be
* written to the flash.
*/
WriteBuffer[ATMEL_COMMAND_OFFSET] = ATMEL_COMMAND_WRITE;
WriteBuffer[ATMEL_ADDRESS_BYTE1_OFFSET] = (u8) (Address >> 16);
WriteBuffer[ATMEL_ADDRESS_BYTE2_OFFSET] = (u8) (Address >> 8);
WriteBuffer[ATMEL_ADDRESS_BYTE3_OFFSET] = (u8) (Address);
/*
* Prepare the write buffer. Fill in the data that is to be written into
* the Flash.
*/
for(Index = 4; Index < (ByteCount + ATMEL_READ_WRITE_EXTRA_BYTES);
Index++) {
WriteBuffer[Index] = (u8)(ATMEL_TEST_BYTE + Index);
}
/*
* Send the write command, address, and data to the Flash.
* No receive buffer is specified since there is nothing to receive.
*/
TransferInProgress = TRUE;
XSpi_Transfer(SpiPtr, WriteBuffer, NULL,
ByteCount + ATMEL_READ_WRITE_EXTRA_BYTES)
;
/*
* Wait till the Transfer is complete and check if there are any errors
* in the transaction.
*/
while (TransferInProgress);
if(ErrorCount != 0) {
ErrorCount = 0;
return XST_FAILURE;
}
return XST_SUCCESS;
}
Wie in Atmel Flash Beispiel erläutert: XSpi_Transfer (SpiPtr, WriteBuffer, Null, ByteCount + ATMEL_READ_WRITE_EXTRA_BYTES); Was ich nicht verstehe ist, dass (im obigen XSpi_transfer-Funktionsbeispiel), wenn der WriteBuffer die Adresse enthält (wie ersichtlich), dann werden die Daten in welcher Variable gespeichert. –