MSP430F149 FLASH写操作之前是不是必须先擦除？而不能重复写入？

Flash 写入前均需保证此地址数据为0XFF，否则会导致写入失败。

所以写入前擦除是对的。

那这也太坑了吧~ flash擦除的最小单位是段。比如说我在某段里存了好多数据，而只对某一个或多个数据修改，我却需要把整段数据都擦除重写吗？有什么更好的办法吗？

我现在用的是MSP430F149啊~ flash MCU的，不是FRAM MCU，

你有针对flash MCU修改一个段内部分数据的例程吗？能不能给我借鉴一下？谢谢！

这个是对information flash 写

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* MSP430 CODE EXAMPLE DISCLAIMER
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//****************************************************************************
// MSP-FET430P140 Demo - Flash In-System Programming, Copy SegA to SegB
//
// Description: This program first erases flash seg A, then it increments all
// values in seg A, then it erases seg B, then copies seg A to seg B.
// Assumed MCLK 550kHz - 900kHz.
// //* Set Breakpoint on NOP in the Mainloop to avoid Stressing Flash *//
//
// MSP430F149
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// | |
//
// M. Mitchell
// Texas Instruments Inc.
// Feb 2005
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.21A
//******************************************************************************

#include <msp430.h>

char value; // 8-bit value to write to segment A

// Function prototypes
void write_SegA (char value);
void copy_A2B (void);

int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
FCTL2 = FWKEY + FSSEL0 + FN0; // MCLK/2 for Flash Timing Generator
value = 0; // Initialize value

while(1) // Repeat forever
{
write_SegA(value++); // Write segment A, increment value
copy_A2B(); // Copy segment A to B
__no_operation(); // SET BREAKPOINT HERE
}
}

void write_SegA (char value)
{
char *Flash_ptr; // Flash pointer
unsigned int i;

Flash_ptr = (char *) 0x1080; // Initialize Flash pointer
FCTL1 = FWKEY + ERASE; // Set Erase bit
FCTL3 = FWKEY; // Clear Lock bit
*Flash_ptr = 0; // Dummy write to erase Flash segment

FCTL1 = FWKEY + WRT; // Set WRT bit for write operation

for (i=0; i<128; i++)
{
*Flash_ptr++ = value; // Write value to flash
}

FCTL1 = FWKEY; // Clear WRT bit
FCTL3 = FWKEY + LOCK; // Set LOCK bit
}

void copy_A2B (void)
{
char *Flash_ptrA; // Segment A pointer
char *Flash_ptrB; // Segment B pointer
unsigned int i;

Flash_ptrA = (char *) 0x1080; // Initialize Flash segment A pointer
Flash_ptrB = (char *) 0x1000; // Initialize Flash segment B pointer
FCTL1 = FWKEY + ERASE; // Set Erase bit
FCTL3 = FWKEY; // Clear Lock bit
*Flash_ptrB = 0; // Dummy write to erase Flash segment B
FCTL1 = FWKEY + WRT; // Set WRT bit for write operation

for (i=0; i<128; i++)
{
*Flash_ptrB++ = *Flash_ptrA++; // Copy value segment A to segment B
}

FCTL1 = FWKEY; // Clear WRT bit
FCTL3 = FWKEY + LOCK; // Set LOCK bit
}