/* set the ETM moule clock source and prescale. 
@无返回  */
void ETM_ClockSet(ETM_Type *pETM, uint8_t u8ClockSource, uint8_t u8ClockPrescale)
/* set the ETM moule clock source and prescale. 
@无返回  */
void ETM_ClockSet(ETM_Type *pETM, uint8_t u8ClockSource, uint8_t u8ClockPrescale)
{
    uint8_t   u8Temp;
    u8Temp  = (pETM->SC & 0xE0);
    u8Temp |= (ETM_SC_CLKS(u8ClockSource & 0x3) | ETM_SC_PS(u8ClockPrescale & 0x7));
    pETM->SC = u8Temp;
}