nz_xFlash.h File Reference

Interface for accessing an external SPI FLASH. More...

#include "HardwareProfile.h"

Go to the source code of this file.

Macros
#define	SPI_FLASH_SECTOR_MASK   (SPI_FLASH_SECTOR_SIZE - 1)
#define	SPI_FLASH_PAGE_MASK   (SPI_FLASH_PAGE_SIZE - 1)
#define	SPIFlashInit   xflashInit
#define	SPIFlashReadArray   xflashReadArray
#define	SPIFlashBeginWrite   xflashBeginWrite
#define	SPIFlashWrite   xflashWrite
#define	SPIFlashWriteArray   xflashWriteArray
#define	SPIFlashEraseSector   xflashEraseSector

Functions
void	xflashInit (void)
void	xflashReadArray (DWORD dwAddress, BYTE *vData, WORD wLen)
void	xflashBeginWrite (DWORD dwAddr)
void	xflashWrite (BYTE vData)
void	xflashWriteArray (BYTE *vData, WORD wLen, BOOL bEraseSector)
void	xflashEraseSector (DWORD dwAddr)

Detailed Description

Interface for accessing an external SPI FLASH.

Author

Modtronix Engineering

Compiler:

MPLAB XC16

Description

Code for reading and writing to and from a external FLASH chip on the SPI bus. This file defines an interface for an external SPI Flash chip. The implementation has to be done in a separate c file by creating instances of these functions. The Netcruzer library contains a default implementations which can be used.

External FLASH Hardware Configuration

The following defines the hardware used for this module, and is located in the board specific file in the "netcruzer/lib" folder (brd_sbc66ec-r2.h for example). They should only be changed if the default EEPROM is replaced with a custom one.

// ********************************************************
// ------------ xFlash Hardware Configuration ------------
// ********************************************************
#define SPI_FLASH_SECTOR_SIZE      (4096ul)
//#define SPI_FLASH_PAGE_SIZE       (0ul)           // SST has no page boundary requirements
#define SPI_FLASH_PAGE_SIZE         (256ul)         // Winbond FLASH has 256 byte pages
#define SPI_FLASH_SIZE              (0x400000ul)    // Flash is 4MByte

Software License Agreement

The software supplied herewith is owned by Modtronix Engineering, and is protected under applicable copyright laws. The software supplied herewith is intended and supplied to you, the Company customer, for use solely and exclusively on products manufactured by Modtronix Engineering. The code may be modified and can be used free of charge for commercial and non commercial applications. All rights are reserved. Any use in violation of the foregoing restrictions may subject the user to criminal sanctions under applicable laws, as well as to civil liability for the breach of the terms and conditions of this license.

THIS SOFTWARE IS PROVIDED IN AN 'AS IS' CONDITION. NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.

File History

2013-08-01, David H. (DH):

• Initial version, modified version of Microchip's SPI Flash file from their TCP/IP stack

Function Documentation

void xflashBeginWrite

(

DWORD

dwAddr)

Prepares the SPI Flash module for writing. Subsequent calls to xflashWrite or xflashWriteArray will begin at this location and continue sequentially. Remarks: Flash parts have large sector sizes, and can only erase entire sectors at once. The Winbond parts for which this library was written have sectors that are 4kB in size. Your application must ensure that writes begin on a sector boundary so that the xflashWrite functions will erase the sector before attempting to write. Entire sectors need not be written at once, so applications can begin writing to the front of a sector, perform other tasks, then later call xflashBeginWrite and point to anaddress in this sector that has not yet been programmed. However, care must taken to ensure that writes are not attempted on addresses that are not in the erased state. The chip will provide no indication that the write has failed, and will silently ignore the command.

!!!!!!!!!!!!!! WINBOND - IMPORTANT !!!!!!!!!!!! Writing to the WINBOND Flash is disabled for up to 10ms after power up. During this time, the CS should be high!

Pre-Condition:

xflashInit has been called.

Parameters

dwAddr

Address where the writing will begin

void xflashEraseSector

(

DWORD

dwAddr)

This function erases a sector in the Flash part. It is called internally by the xflashWrite functions whenever a write is attempted on the first byte in a sector.

Remarks: See Remarks in xflashBeginWrite for important information about Flash memory parts.

Pre-Condition:

xflashInit has been called.

Parameters

dwAddr

The address of the sector to be erased.

void xflashInit

(

void

)

Initializes SPI Flash module. This function is only called once during the lifetime of the application. Internal: This function sends WRDI to clear any pending write operation, and also clears the software write-protect on all memory locations.

void xflashReadArray	(	DWORD	dwAddress,
		BYTE *	vData,
		WORD	wLen
	)

Reads an array of bytes from the SPI Flash module.

Pre-Condition:

xflashInit has been called, and the chip is not busy (should be handled elsewhere automatically.)

Parameters

dwAddress	Address from which to read
vData	Where to store data that has been read
wLen	Length of data to read

void xflashWrite

(

BYTE

vData)

This function writes a byte to the SPI Flash part. If the current address pointer indicates the beginning of a 4kB sector, the entire sector will first be erased to allow writes to proceed. If the current address pointer indicates elsewhere, it will be assumed that the sector has already been erased. If this is not true, the chip will silently ignore the write command.

Remarks: See Remarks in xflashBeginWrite for important information about Flash memory parts.

!!!!!!!!!!!!!! WINBOND - IMPORTANT !!!!!!!!!!!! Writing to the WINBOND Flash is disabled for up to 10ms after power up. During this time, the CS should be high!

Pre-Condition:

xflashInit() and xflashBeginWrite() have been called, and the current address is either the front of a 4kB sector or has already been erased.

Parameters

vData

The byte to write to the next memory location.

void xflashWriteArray	(	BYTE *	vData,
		WORD	wLen,
		BOOL	bEraseSector
	)

This function writes an array of bytes to the SPI Flash part. When the address pointer crosses a sector boundary (and has more data to write), the next sector will automatically be erased. If the current address pointer indicates an address that is not a sector boundary and is not already erased, the chip will silently ignore the write command until the next sector boundary is crossed.

Remarks: See Remarks in xflashBeginWrite() for important information about Flash memory parts.

!!!!!!!!!!!!!! WINBOND - IMPORTANT !!!!!!!!!!!! Writing to the WINBOND Flash is disabled for up to 10ms after power up. During this time, the CS should be high!

Pre-Condition:

xflashInit() and xflashBeginWrite() have been called, and the current address is either the front of a sector or has already been erased.

Parameters

vData	The array to write to the next memory location
wLen	The length of the data to be written
bEraseSector	When true, will erase secotor if given address is on sector boundry (is first byte of new sector)