Add 'press Q to exit' function

bme280_util.z80

@@ -13,10 +13,15 @@ humid_offset    equ     09eh
 bdos            equ     0005h
 conout          equ     02h
 conin           equ     01h
+dconio          equ     06h
 printstr        equ     09h
 
 
 start:
+                ld      c,printstr              ; tell the operator how to quit
+                ld      de,quitmsg
+                call    bdos
+
                 call    init_lcd
                 call    init_siob
                 call    lcd_delay
@@ -42,11 +47,14 @@ start:
 main:
                 call    read_char_b
                 call    parse_char
-                ld      c,11
+                ld      c,dconio                ; direct console i/o, no echo
+                ld      e,0ffh                  ; ff polls, returning zero if no key
                 call    bdos
-                or      a
-                jr      z,main
-                ret
+                cp      a,051h                  ; Q
+                ret     z
+                cp      a,071h                  ; q
+                ret     z
+                jr      main                    ; no key, or a key we ignore
 
 init_siob:
                 ld      a,018h                  ; channel reset
@@ -240,6 +248,8 @@ clabel:         DB      'degree C',0
 plabel:         DB      'hPa',0
 hlabel:         DB      '% RH',0
 
+quitmsg:        DB      'Press Q to quit',0dh,0ah,'$'
+
 char_max        equ     15
 char_cnt        DB      0