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对于Flash存储器的驱动,采用的Flash芯片为SST公司的SST39VF1601
SST25LF080A.rar
  • SST25LF080A.txt
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内容介绍
Software Driver SST25LF080A 2 Mbit(1M x 8) Serial Flash Memory February 25th, 2004, Rev. 1.0 ABOUT THE SOFTWARE This application note provides software driver examples for 25LF080A, Serial Flash. Extensive comments are included in each routine to describe the function of each routine. The interface coding uses polling method rather than the SPI protocol to interface with these serial devices. The functions are differentiated below in terms of the communication protocols (uses Mode 0) and specific device operation instructions. This code has been designed to compile using the Keil compiler. ABOUT THE 25LF080A Companion product datasheets for the 25LF080A should be reviewed in conjunction with this application note for a complete understanding of the device. Device Communication Protocol(pinout related) functions: Functions Function ------------------------------------------------------------------ init Initializes clock to set up mode 0. Send_Byte Sends one byte using SI pin to send and shift out 1-bit per clock rising edge Get_Byte Receives one byte using SO pin to receive and shift in 1-bit per clock falling edge CE_High Sets Chip Enable pin of the serial flash to high CE_Low Clears Chip Enable of the serial flash to low Hold_Low Clears Hold pin to make serial flash hold Unhold Unholds the serial flash WP_Low Clears WP pin to make serial flash write protected UnWP Disables write protection pin Note: The pin names of the 25LF080A are used in this application note. The associated test code will not compile unless these pinouts (SCK, SI, SO, SO, CE, WP, Hold) are pre-defined on your software which should reflect your hardware interfaced. Device Operation Instruction functions: Functions Function ------------------------------------------------------------------ Read_Status_Register Reads the status register of the serial flash EWSR Enables the Write Status Register WRSR Performs a write to the status register WREN Write enables the serial flash WRDI Write disables the serial flash Read_ID Reads the manufacturer ID and device ID Read Reads one byte from the serial flash and returns byte(max of 20 MHz CLK frequency) Read_Cont Reads multiple bytes(max of 20 MHz CLK frequency) HighSpeed_Read Reads one byte from the serial flash and returns byte(max of 33 MHz CLK frequency) HighSpeed_Read_Cont Reads multiple bytes(max of 33 MHz CLK frequency) Byte_Program Program one byte to the serial flash Auto_Add_IncA Initial Auto Address Increment process Auto_Add_IncB Successive Auto_Address_Increment process after AAI initiation Chip_Erase Erases entire serial flash Sector_Erase Erases one sector (4 KB) of the serial flash Block_Erase Erases one block (32 KB) of the serial flash Wait_Busy Polls status register until busy bit is low Wait_Busy_AAI Polls status register until busy bit is low for AAI programming WREN_Check Checks to see if WEL is set WREN_AAI_Check Checks to see if WEL and AAI mode is set "C" LANGUAGE DRIVERS */ /********************************************************************/ /* Copyright Silicon Storage Technology, Inc. (SST), 1994-2004 */ /* Example "C" language Driver of 25LF080A Serial Flash */ /* Conrado Canio, Silicon Storage Technology, Inc. */ /* */ /* Revision 1.0, February 25th, 2004 */ /* */ /* */ /********************************************************************/ #include <stdio.h> #include <stdlib.h> /* Function Prototypes */ void init(); void Send_Byte(unsigned char out); unsigned char Get_Byte(); void CE_High(); void CE_Low(); void Hold_Low(); void Unhold(); void WP_Low(); void UnWP(); unsigned char Read_Status_Register(); void EWSR(); void WRSR(byte); void WREN(); void WRDI(); unsigned char Read_ID(ID_addr); unsigned char Read(unsigned long Dst); void Read_Cont(unsigned long Dst, unsigned long no_bytes); unsigned char HighSpeed_Read(unsigned long Dst); void HighSpeed_Read_Cont(unsigned long Dst, unsigned long no_bytes); void Byte_Program(unsigned long Dst, unsigned char byte); void Auto_Add_IncA(unsigned long Dst, unsigned char byte); void Auto_Add_IncB(unsigned char byte); void Chip_Erase(); void Sector_Erase(unsigned long Dst); void Block_Erase(unsigned long Dst); void Wait_Busy(); void Wait_Busy_AAI(); void WREN_Check(); void WREN_AAI_Check(); void Verify(unsigned char byte, unsigned char cor_byte); unsigned char idata upper_128[128]; /* global array to store read data */ /* to upper RAM area from 80H - FFH */ /************************************************************************/ /* PROCEDURE: init */ /* */ /* This procedure initializes the SCK to low. Must be called prior to */ /* setting up mode 0. */ /* */ /* Input: */ /* None */ /* */ /* Output: */ /* SCK */ /************************************************************************/ void init() { SCK = 0; /* set clock to low initial state */ } /************************************************************************/ /* PROCEDURE: Send_Byte */ /* */ /* This procedure outputs a byte shifting out 1-bit per clock rising */ /* edge on the the SI pin(LSB 1st). */ /* */ /* Input: */ /* out */ /* */ /* Output: */ /* SI */ /************************************************************************/ void Send_Byte(unsigned char out) { unsigned char i = 0; for (i = 0; i < 8; i++) { if ((out & 0x80) == 0x80) /* check if MSB is high */ SI = 1; else SI = 0; /* if not, set to low */ SCK = 1; /* toggle clock high */ out = (out << 1); /* shift 1 place for next bit */ SCK = 0; /* toggle clock low */ } } /************************************************************************/ /* PROCEDURE: Get_Byte */ /* */ /* This procedure inputs a byte shifting in 1-bit per clock falling */ /* edge on the SO pin(LSB 1st). */ /* */ /* Input: */ /* SO */ /* */ /* Output: */ /* None */ /************************************************************************/ unsigned char Get_Byte() { unsigned char i = 0, in = 0, temp = 0; for (i = 0; i < 8; i++) { in = (in << 1); /* shift 1 place to the left or shift in 0 */ temp = SO; /* save input */ SCK = 1; /* toggle clock high */ if (temp == 1) /* check to see if bit is high */ in = in | 0x01; /* if high, make bit high */ SCK = 0; /* toggle clock low */ } return in; } /************************************************************************/ /* PROCEDURE: CE_High */ /* */ /* This procedure set CE = High. */ /* */ /* Input: */ /* None */ /* */ /* Output: */ /* CE */ /* */ /************************************************************************/ void CE_High() { CE = 1; /* set CE high */ } /************************************************************************/ /* PROCEDURE: CE_Low */ /* */ /* This procedure drives the CE of the device to low. */ /* */ /* Input: */ /* None */ /* */ /* Output: */ /* CE */ /* */ /************************************************************************/ void CE_Low() { CE = 0; /* clear CE low */ } /******************************************************************
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