D_PCR_REG
r = _reg_read_4(D_PCR_REG);
_reg_write_4(D_PCR_REG, r | D_PCR_CPC_BIT(ch));
_reg_write_4(D_PCR_REG, _reg_read_4(D_PCR_REG) & ~D_PCR_CPC_BIT(ch))