UART_DM_NO_CHARS_FOR_TX
volatile uint32_t * UART_DM_NO_CHARS_FOR_TX = (uint32_t *)(UART_BASE + 0x40);
*UART_DM_NO_CHARS_FOR_TX = 1;
uart_setreg(bas, UART_DM_NO_CHARS_FOR_TX, 1);