UART_BIT_NUM
conf0 &= ~(UART_PARITY_EN | UART_PARITY | UART_BIT_NUM | UART_STOP_BIT_NUM);
conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_5);
conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_6);
conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_7);
conf0 |= FIELD_PREP(UART_BIT_NUM, UART_BIT_NUM_8);