/* lock the FMC bank0 operation this function can be used for all GD32F10X devices. for GD32F10x_MD and GD32F10x_HD, this function unlocks bank0. for GD32F10x_XD and GD32F10x_CL with flash no more than 512KB, it is equivalent to fmc_unlock function.  */
void fmc_bank0_lock(void)
/* lock the FMC bank0 operation this function can be used for all GD32F10X devices. for GD32F10x_MD and GD32F10x_HD, this function unlocks bank0. for GD32F10x_XD and GD32F10x_CL with flash no more than 512KB, it is equivalent to fmc_unlock function.  */
void fmc_bank0_lock(void)
{
    FMC_CTL0 |= FMC_CTL0_LK;
}