Forum Post: RE: The MSP430F5659 with xt2 crystal osc 19.2 MHz write to flash memory problem.

I had find any way to solve this problem and it's realy working, but I don't know why ? Before the call to the flash memory writing function I set the master clock dividet to 2, then return to the previous state this way: UCSCTL5 |= DIVM0; FCTL3 = FWKEY; FCTL1 = FWKEY + WRT; __data20_write_char(addr,byte); FCTL3 = FWKEY; FCTL1 = FWKEY + LOCK; UCSCTL5 &= ~DIVM0;