dportram.c

DSP通过双口RAM和ISP1581实现下位机的USB固件程序

#include <AT89X52.H>

sbit ramcs=P1^2;
sbit rambusy=P1^3;


void WriteRamChar(unsigned int addr,unsigned char wdata)
{
unsigned char xdata *exAddress;
	exAddress = addr;
	//while(rambusy==0);	
	*exAddress = wdata;
	
}

unsigned char ReadRamChar(unsigned int addr)
{
unsigned char xdata *exAddress;
unsigned char ret;
	exAddress = addr;
	//while(rambusy==0);
	//while(rambusy==0);
	ret=*(exAddress);
return ret;
	
}


void init_ram()
{
unsigned int i;
EA=0;
ramcs=0;
for(i=0;i<16;i++)
WriteRamChar(i,0);
ramcs=1;
EA=1;
}

unsigned char WriteRam(unsigned char num,unsigned char * buf)
{
unsigned char j,i;
unsigned char endaddr;
if(num<65)
{

endaddr=num;
EA=0;
ramcs=0;
//WriteRamChar(1,0x55);
//WriteRamChar(6,0);

for(i=0;i<endaddr;i++)
WriteRamChar(i,buf[i]);

//WriteRamChar(6,num);
ramcs=1;
EA=1;
j=1;
}
else
j=0;
return j;
}

void ReadRam(unsigned char num,unsigned char * buf)
{
unsigned char i;
unsigned char endaddr;
if(num<65)
{
endaddr=num;
EA=0;
ramcs=0;
for(i=0;i<endaddr;i++)
buf[i]=ReadRamChar(i);
WriteRamChar(0,0xAA);
ramcs=1;
EA=1;

}
}