flash.c

这个代码是用ADS1.2平台开发的一个mp3播放器。

#include "..\inc\board.h"
#include "..\inc\bios.h"  
#include "..\inc\flash.h"

unsigned long flash_base;
unsigned short mfr_id;
unsigned short dev_id;


void send_cmd(unsigned long addr,unsigned char cmd)
{
    *(unsigned short *)(addr*2)=cmd;
}
 
void send_unlock()   
{
	*(unsigned short *)((ROM_BASE+0x5555)*2) =0xAA;
	*(unsigned short *)((ROM_BASE+0x2AAA)*2) =0x55;
}

 

int probe_chip()
{
	int i;


	/* Enter autoselect mode. */
	send_unlock();
	send_cmd(ROM_BASE+0x5555, 0x90);

	mfr_id =*(unsigned short *)(ROM_BASE+0x0*2);
	dev_id =*(unsigned short *)(ROM_BASE+0x1*2);
	
	send_cmd(ROM_BASE, 0xf0);

	return 0;
}

int flash_is_busy(unsigned long addr1)
{
    unsigned short d1,d2;
	d1=*(unsigned short*)(addr1*2) & D6_MASK;
	d2=*(unsigned short*)(addr1*2) & D6_MASK;
	return(d1!=d2);
//    return((*(unsigned short*)addr1 & D7_MASK)==0);
}


int flash_erase()
{
    int times_left,ret;
	send_unlock();
	send_cmd(ROM_BASE+0x5555, 0x80);
	send_unlock();
	send_cmd(ROM_BASE+0x5555, 0x10);
	
	delay(20);
	times_left = 0x500000;
	while (times_left-- && flash_is_busy(0));

	if (!times_left)
	{
		ret = -1;
	}
	send_cmd(ROM_BASE, 0xf0);

	return ret;
}

int flash_read(unsigned long from,unsigned long len,unsigned short *buf)
{
	int i;
	unsigned short buff[100];
	for(i=0;i<100;i++)
	  buff[i]=*(unsigned short *)i*2;
	
	return 0;
}
int write_one_word(unsigned long addr, unsigned short dat)
{
	int times_left;
	int ret = 0;

	send_unlock();
	send_cmd(ROM_BASE+0x5555, 0xA0);
	
	*(unsigned short *)(ROM_BASE+addr)= dat;
	
	delay(20);
	times_left = 200000;
	while (times_left-- && flash_is_busy(ROM_BASE+addr));

	if (!times_left)
	{
		ret = -1;
	}

	return ret;
}
 int flash_write(unsigned long to,unsigned long len,unsigned short *buf)
{
    int n;
    unsigned short dat,*buff;
     
    to=0;
    len=0x2000;
    buff=(unsigned short *)0x0c000000;
    
	for (n =0; n <len;n++)
	{
	  dat=buff[n];
	  write_one_word(n<<1,dat);
    }
      
    
	return 0;
}

int flash_init()
{
	int i;
	unsigned short buf[100];


	probe_chip();
    if(flash_erase()==0)
    {
    }
    
    flash_write(0,0x100,buf);

	return 0;
}