;X KEY? -- f return true if char waiting HEADER(XT_USART_RXQ_POLL,3,"rx?",DOCOLON) .dw XT_PAUSE .dw XT_DOLITERAL .dw bm_USART_RXRD .dw XT_DUP .dw XT_DOLITERAL .dw USART_RX_CFG .dw XT_CFETCH .dw XT_AND .dw XT_EQUAL .dw XT_EXIT