sst29xe010.txt

SST 系列Nor flash 的读写源码

Software
Drivers

29EE010 / 29LE010 / 29VE010
1 Megabit Page Mode EEPROM

December 1997


ABOUT THE SOFTWARE
This application note provides software driver examples for SST抯 29EE010, 1 Megabit Page Mode 
EEPROM, that can be used in any microprocessor based system. Software driver examples used in this 
document utilize two programming languages: (a) high -level "C" for broad platform support and (b) opti-
mized 8086 assembly language. In many cases, software driver routines can be inserted "as is" into the 
main body of code being developed by the system software developers. Extensive comments are included 
in each routine to describe the function of each routine. The driver in "C" language can be used with many 
microprocessors and microcontrollers, while the 8086 assembly language provides an optimized solution 
for 8086 microprocessors.
NOTE:
The 29EE010 is for 5.0 volt applications, the 29LE010 is for 3.0 volts application, and the 29VE010 is for 
2.7 volt applications. Device functionality is identical for application of this software. For convenience, only 
the 29EE010 will be referenced in the example codes provided.
ABOUT THE 29EE010
Companion product datasheets for the 29EE010 should be reviewed in conjunction with this application 
note for a complete understanding of the device.
The recommended method for writing the 29EE010 employs the JEDEC approved "enable software pro-
tection page write" (SDP) algorithm. Using this method, any write operation (128 bytes) requires the 
inclusion of a series of three byte-load operations, which precede the data loading operation. The three 
byte-load sequence enables the SDP option during page write operation. SDP provides optimal protection 
from inadvertent write cycles, e.g., those triggered by noise during the system power-up or power-down. 
After the initial data byte-load cycle, the host must continue to load a byte into the page buffer within the 
byte-load cycle time (TBLC) of 100 祍 for the 29EE010 to stay in the page load cycle. Additional bytes can 
then be loaded within the same page, in any order. The page load cycle will terminate if no additional byte 
is loaded into the page buffer within 200 祍 (TBLCO) from the last byte-load cycle, i.e. no subsequent WE# 
high-to-low transition after the last rising edge of WE#.


	Both the C and 8086 assembly code in the document contain the following routines, in this order:
	Name	Function
	Check_SST_29EE010	Check manufacturer and device ID
	Alternate_Check_SST_29EE010	The OLD six-byte sequence to check manufacture and de-
vice ID
	Write_29EE010	Alter data
	Check_Toggle_Ready	End of write detection using Toggle bit
	Check_Data_Polling	End of write detection using Data# polling
	Enable_Chip_Data_Protection	Enable JEDEC standard software data protection
	




"C" LANGUAGE DRIVERS

/******************************************************************************************************/
/* Copyright Silicon Storage Technology, Inc. (SST), 1994-1997	                                      */
/* Example "C" language Driver of 29EE010 1 Mbit Page Mode EEPROM	                              */
/* Chi Chung Yin, Silicon Storage Technology	                                                      */
/*		                                                                                      */
/* Revision 3.0, April 8, 1997	                                                                      */
/*		                                                                                      */
/* This file requires these external "timing"  routines:	                                      */
/*		                                                                                      */
/*	1.)  Delay_1_Milli_Second	                                                              */
/*	2.)  Delay_10_Milli_Second	                                                              */
/*	3.)  Delay_10_Micro_Second	                                                              */
/******************************************************************************************************/

#define FALSE			0
#define TRUE			(~FALSE)

#define ROW_SIZE		128	        /* Must be 128 bytes for 29EE010           */

#define SST_ID			0xBF		/* SST Manufacturer抯 ID code              */
#define SST_29EE010		0x07		/* SST 29EE010 device code                 */
						/* NOTE-Use "0x08" for 29LE010 and 29VE010 */

typedef unsigned char 		BYTE;

/*__________________________________________________________________*/
/*                                                                  */
/*                           EXERNAL ROUTINES                       */     		
/*__________________________________________________________________*/

extern void	Delay_1_Milli_Second();
extern void	Delay_10_Milli_Second();
extern void	Delay_10_Micro_Second();
extern void	Check_Toggle_Ready(BYTE far *);
extern void 	Check_Data_Polling(BYTE far *, BYTE);





/******************************************************************************************************/
/* PROCEDURE: 		Check_SST_29EE010	                                                      */
/*				                                                                      */
/* This procedure  decides whether a  physical hardware device has a SST's	                      */
/* 29EE010  1 Mbit Page Mode EEPROM installed or not. (JEDEC Standard routine)	                      */
/*  				                                                                      */
/*												      */
/* Input:				                                                              */
/*           None			                                                              */
/*				                                                                      */
/*												      */	
/* Output:			                                                                      */
/*  	return -1:  indicates not a SST 29EE010	                                                      */
/*      return 0:   indicates is  a SST 29EE010	                                                      */
/******************************************************************************************************/

int Check_SST_29EE010()
{
	BYTE far  *Temp;
	BYTE SST_id1;
	BYTE SST_id2;
	int  ReturnStatus;

	/*  Issue the Software Product ID code to 29EE010   */  

	Temp  = (BYTE far *)0xE0005555;	          /* set up address to be E000:5555h	*/
       *Temp = 0xAA;			          /* write data 0xAA to the address	*/
	Temp  = (BYTE far *)0xE0002AAA;	          /* set up address to be E000:2AAAh	*/
       *Temp = 0x55;			          /* write data Ox55 to the address	*/
	Temp  = (BYTE far *)0xE0005555;	          /* set up address to be E000:5555h	*/
       *Temp = 0x90;			          /* write data 0x90 to the address	*/

	Delay_10_Milli_Second();

	/* Read the product ID from 29EE010 */

	Temp  = (BYTE far *)0xE0000000;	          /* set up address to be E000:0000h	*/
	SST_id1  =  *Temp;		          /* get first ID byte	                */
	Temp  =  (BYTE far *)0xE0000001;          /* set up address to be E000:0001h	*/

	if ((SST_id1 == SST_ID) && (SST_id2 ==SST_29EE010))  
		ReturnStatus = 0;
	else
		ReturnStatus = -1;

	/* Issue the Soffware Product ID Exit code thus returning the 29EE010	*/
	/* to the read operating mode	                                        */

	Temp  = (BYTE far *)0xF0005555;	   /* set up address to be F000:5555h	*/
       *Temp = 0xAA;			   /* write data 0xAA to the address	*/
	Temp  = (BYTE far *)0xF0002AAA;	   /* set up address to be F000:2AAAh	*/
       *Temp = 0x55;			   /* write data 0x55 to the address	*/
	Temp  = (BYTE far *)0xF0005555;	   /* set up address to be F000:5555h	*/
       *Temp =0xF0;			   /* write data 0xF0 to the address	*/

	Delay_10_Milli_Second();

	return(ReturnStatus);
}



/******************************************************************************************************/
/* PROCEDURE: 		Alternate_Check_SST_29EE010	                                              */
/*				                                                                      */
/* This procedure  decides whether a  physical hardware device has a SST	                      */
/* 29EE010 1 Mbit Page Mode EEPROM installed or not.	                                              */
/* ALTERNATIVE 6 BYTE ID SEQUENCE	                                                              */
/*				                                                                      */
/* Input:				                                                              */
/*           None										      */
/*												      */
/* Output:											      */
/*  	return -1:  indicates not a SST 29EE010							      */
/*      return 0:   indicates is  a SST 29EE010						              */
/******************************************************************************************************/

int Alternate_Check_SST_29EE010()
{
	BYTE far  *Temp;
	BYTE SST_id1;
	BYTE SST_id2;
	int  ReturnStatus;

	/*  Issue the Software Product ID code to 29EE010  */  

	Temp  = (BYTE far *)0xE0005555;	         /* set up address to be E000:5555h	*/
	*Temp = 0xAA;			         /* write data 0xAA to the address	*/
	Temp  = (BYTE far *)0xE0002AAA;	         /* set up address to be E000:2AAAh	*/
	*Temp = 0x55;			         /* write data 0x55 to the address	*/
	Temp  = (BYTE far *)0xE0005555;	         /* set up address to be E000:5555h	*/
	*Temp = 0x80;			         /* write data 0x80 to the address	*/
	Temp  = (BYTE far *)0xE0005555;	         /* set up address to be E000:5555h	*/
	*Temp = 0xAA;			         /* write data 0xAA to the address	*/
	Temp  = (BYTE far *)0xE0002AAA;	         /* set up address to be E000:2AAAh	*/
	*Temp = 0x55;			         /* write data 0x55 to the address	*/
	Temp  = (BYTE far *)0xE0005555;	         /* set up address to be E000:5555h	*/
	*Temp =0x60;			         /* write data 0x60 to the address	*/

	Delay_10_Milli_Second();

	/* Read the product ID from 29EE010 */

	Temp  = (BYTE far *)0xE0000000;	         /* set up address to be E000:0000h	*/
	SST_id1  =  *Temp;		         /* get first ID byte	                */
	Temp  =  (BYTE far *)0xE0000001;	 /* set up address to be E000:0001h	*/

	if ((SST_id1 == SST_ID) && (SST_id2 ==SST_29EE010))  
		ReturnStatus = 0;
	else
		ReturnStatus = -1;

	/* Issue the Soffware Product ID Exit code thus returning the 29EE010	*/
	/* to the read operating mode	*/

	Temp  = (BYTE far *)0xE0005555;	     /* set up address to be E000:5555h	*/
	*Temp = 0xAA;			     /* write data 0xAA to the address	*/
	Temp  = (BYTE far *)0xE0002AAA;	     /* set up address to be E000:2AAAh	*/