USC_PCTRL_SEL1
src &= ~USC_PCTRL_SEL1;
src |= ((src1 << 8) & USC_PCTRL_SEL1) | USC_PCTRL_CLR1;
*srcp1 = (src & USC_PCTRL_SEL1) >> 8;
src &= ~USC_PCTRL_SEL1;
src |= ((src1 << 8) & USC_PCTRL_SEL1) | USC_PCTRL_CLR1;
*srcp1 = (src & USC_PCTRL_SEL1) >> 8;