USC_PCTRL_SEL0
src &= ~USC_PCTRL_SEL0;
src |= ((src0 << 0) & USC_PCTRL_SEL0) | USC_PCTRL_CLR0;
*srcp0 = (src & USC_PCTRL_SEL0) >> 0;
src &= ~USC_PCTRL_SEL0;
src |= ((src0 << 0) & USC_PCTRL_SEL0) | USC_PCTRL_CLR0;
*srcp0 = (src & USC_PCTRL_SEL0) >> 0;