I am using 56F8345 and want to test how security method works. Before writing back door key to FM configuration field, I just want to create a function to write data to flash memory.
I wrote a function according to 56f8300 peripheral user manual . It is able to write data to Data_flash memory since I could see value changes in debug mode. However, it seems not work for program flash memory.
Here is the code for writing data to program flash ( to write data to data flash , only need change address and bits in register FMCR):
#define data_space 1
#define prog_space 0
#define data_flash_address (*((volatile word *)0x00001000)) // pick up one data flash memory unit for writing test
#define prog_flash_address (*((volatile word *)0x0000FE00)) // pick up one prog flash memory unit for writing test
//create a function to do write on program flash memory
void write_on_progflash( void);
void write_on_progflash( void)
{
//first check the FMCLKD, if it's not written, no further operation
if(FMCLKD &0x0080)
{
asm(nop); //FMCLKD is written
}
else
FMCLKD =0x0032; //DIV=50 PDIV=0 then FMCLKD =20Mhz/2/51=196KHZ
asm(nop);
// select data flash
FMCR =(FMCR & 0x0fffc)| prog_space ;
FMCR &=0x0FFDF ;//Clear KEYACC bit to disable Security Key Writing
//test LOCK bit on FMCR
if(FMCR&0x400)
return ; // LOCK is set, so no way to change FMPORT
asm(nop);
FMPROT =0 ; //make the flash space be able to be written
asm(nop);
//check the status of FMUSTAT, CBEIF is set?
while ((FMUSTAT &0x0080)==0)
{
asm(nop); //CBEIF is 0, buffer is full
}
asm(nop);
asm(nop);
asm(nop);
//now flash is ready for operation
//Before writing data to flash, erase first
prog_flash_address =0;
FMCMD = 0x040; //page erase command
FMUSTAT |=0x080; //set up CBEIF
//check any error happens?
if(FMUSTAT & 0x0030)
return; // error happens
// no error? check erase finished or not
while((FMUSTAT & 0x0c0)!=0xc0)
{
asm(nop);
}
asm(nop);
asm(nop);
asm(nop);
//ok, now able to write
prog_flash_address =99;
asm(nop);
asm(nop);
FMCMD =0x020;
FMUSTAT |=0x080; //set up CBEIF
//check any error happens?
if(FMUSTAT & 0x0030)
return; // error happens
// no error? check erase finished or not
while((FMUSTAT & 0x0c0)!=0xc0)
{
asm(nop);
}
asm(nop);
asm(nop);
asm(nop);
}
Any ideas, thanks in advance.
