;;; serialxmit.s
;;; counts from 0x21 to 0x5a on 68HC11 serial port and then repeats
	
base=	0x1000
scsr=	0x102e			; serial comms status reg
scdr=	0x102f			; serial comms data reg

	ldx #base		; pointer to register base
loop:	ldaa #0x21		; start with ASCII 0x21 to transmit
xmit:	staa <scdr,x		; transmit reg a
	brclr <scsr,x,#0x40,.	; loop here until byte transmitted
	inca			; inc char to be transmitted
	cmpa #0x5B		; see if it's beyond ASCII 0x5a
	bne xmit		; no, send the next one
	bra loop		; reset char to 0x21