CCS/MSP430G2553: Store Float value into flash

Joe Shoshana

Expert 1030 points

Part Number: MSP430G2553

Tool/software: Code Composer Studio

Hi,

I wanted to know hoe to store float value into flash, into 2 words or 4 bytes?

thank you all.

over 8 years ago

0 stevenh over 8 years ago

Guru 20045 points

const double var1;

Or

const float var1;

Stephen

0 Joe Shoshana over 8 years ago in reply to stevenh

Expert 1030 points

Thank you for the reply
But, i want to write it in information memory or main memory
for now i establish to write char short and long (2 shorts) into the memory.

0 stevenh over 8 years ago in reply to Joe Shoshana

Guru 20045 points

Hello Joe,

I am confused. In your initial post, you said you wanted to place the floating point number in flash. Adding const to the variable declaration will place the variable in flash.

Could you please post a small snippet of code that shows what you are currently doing.

Thanks,

Stephen

0 Joe Shoshana over 8 years ago in reply to stevenh

Expert 1030 points

here's an example of writing char data into memory

void WriteToFlash(char* address, char val)
{
	char* flash_ptr;
	FCTL3 = FWKEY;
	flash_ptr = address;              // Initialize Flash pointer
	while(FCTL3 & BUSY);
	FCTL1 = FWKEY + WRT;
	*flash_ptr = val;
	while(FCTL3 & BUSY);
	FCTL1 = FWKEY;                            // Clear WRT bit
	FCTL3 = FWKEY + LOCK;                     // Set LOCK bit
}

her's another example to write long data:

	WriteShortToFlash((short*)MEM_SLOPE_H,(short)(wt_slope & 0xFFFF));// Slope
	WriteShortToFlash((short*)MEM_SLOPE_L,(short)((wt_slope >> 16) & 0xFFFF));// Slope

void WriteShortToFlash(short* address, short val)
{
	short* flash_ptr;
	FCTL3 = FWKEY;
	flash_ptr = address;              // Initialize Flash pointer
	while(FCTL3 & BUSY);
	FCTL1 = FWKEY + WRT;
	*flash_ptr = val;
	while(FCTL3 & BUSY);
	FCTL1 = FWKEY;                            // Clear WRT bit
	FCTL3 = FWKEY + LOCK;                     // Set LOCK bit
}

I want to know how to write a float to memory

Thank you for your help

0 stevenh over 8 years ago in reply to Joe Shoshana

Guru 20045 points

Ok. I think the following should work.

Stephen

float var1 = 3.14159;
unsigned long int wt_slope;


int main(void)
{
    wt_slope =  *(unsigned long int*)&var1;
    WriteShortToFlash((short*)MEM_SLOPE_H,(short)(wt_slope & 0xFFFF));// Slope
    WriteShortToFlash((short*)MEM_SLOPE_L,(short)((wt_slope >> 16) & 0xFFFF));// Slope
}

0 stevenh over 8 years ago in reply to Joe Shoshana

Guru 20045 points

Did that solve your issue? If so, please select verify.

Thanks,
Stephen

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CCS/MSP430G2553: Store Float value into flash