MS51的24MHz时钟怎么设置

只看该作者 · 2021-9-27 15:59

手册上没有看明白怎么设置，请指点一下

只看该作者 · 2021-9-29 17:52

/**
  * @brief This API configures modify system HIRC value
  * @param[in] u8FsysMode . Valid values are:
  *                      - \ref HIRC_24                :Internal HIRC 24MHz .
  *                      - \ref HIRC_16                :Internal HIRC 16MHz.
  *                      - \ref HIRC_166             :Internal HIRC 16.6MHz.
  * @NOTE    None.
  * @exmaple : MODIFY_HIRC(HIRC_24);
  */
void MODIFY_HIRC(unsigned char u8HIRCSEL)
{
unsigned char data hircmap0,hircmap1;
unsigned int trimvalue16bit;
/* Check if power on reset, modify HIRC */
SFRS = 0 ;
switch (u8HIRCSEL)
{
   case HIRC_24:
      IAPAL = 0x38;
   break;
   case HIRC_16:
      IAPAL = 0x30;
   break;
   case HIRC_166:
      IAPAL = 0x30;
   break;
}
set_CHPCON_IAPEN;
IAPAH = 0x00;
IAPCN = READ_UID;
set_IAPTRG_IAPGO;
hircmap0 = IAPFD;
IAPAL++;
set_IAPTRG_IAPGO;
hircmap1 = IAPFD;
clr_CHPCON_IAPEN;
switch (u8HIRCSEL)
{
   case HIRC_166:
      trimvalue16bit = ((hircmap0 << 1) + (hircmap1 & 0x01));
      trimvalue16bit = trimvalue16bit - 15;
      hircmap1 = trimvalue16bit & 0x01;
      hircmap0 = trimvalue16bit >> 1;

   break;
   default: break;
}
TA = 0xAA;
TA = 0x55;
RCTRIM0 = hircmap0;
TA = 0xAA;
TA = 0x55;
RCTRIM1 = hircmap1;
clr_CHPCON_IAPEN;
PCON &= CLR_BIT4;
}