; > ECHO tests console by echoing characters
;   Uses polling to check UART is free
;
        ORG     O1000
GET:    BIT     @#O177560,#200  ; test RCSR - bit7 set=char rec'd
        BEQ     GET
        MOV     @#O177562,R1    ; get character
SND:    BIT     @#O177564,#200  ; test TCSR - bit7 set=ready
        BEQ     SND
        MOV     R1,@#O177566    ; send character
        BR      GET             ; repeat continuously
