PICAXE program to use Snap Circuits keyboard (U26) with LED MC (U29)

snap_circuits_led_mc_keyboard.bas

; calling convention
symbol arg1 = b0
symbol arg2 = b1
symbol arg3 = b2
;symbol arg1w = w3

symbol shift_out_current_mask = b3
symbol shift_out_temp = b4

symbol main_last = b5
symbol main_last_mod = b6
symbol main_valid_cnt = b7
;symbol last_number = b20
;symbol main_last = b19
;symbol measure_pulse_out = w13

; pin definitions
symbol SHIFT_DATA = 1
symbol SHIFT_CLK = 0
symbol KEYBD_IN = 3
;symbol "C = %00000000

;main2:
;	arg1 = "A"
;    gosub display_letter
;    arg1 = "B"
;    gosub display_letter
;    end
;main:
main:
	gosub measure_pulse
    
    if arg1 = 0 then
    	main_valid_cnt = 0
    else
    	main_valid_cnt = main_valid_cnt + 1
    endif
    
    if main_valid_cnt < 20 then
    	goto main
    endif
    
    b27 = arg1
    
    arg2 = 0
	select case arg1
   		case 70 to 74
        	arg1 = "A"
        case 66 to 69
        	arg1 = "A"
            arg2 = 1
        case 60 to 65
        	arg1 = "B"
    endselect
    
    b26 = arg1
    b25 = arg2
    
    if arg1 != main_last or arg2 != main_last_mod then
    	gosub display_letter
        pause 400
        ;debug ; show it on the display before serial messes it up...
    endif
    
    main_last = arg1
    main_last_mod = arg2
    
    goto main
	;arg1 = "C"
   
	;setint 8,8
	;gosub measure_pulse
    ;arg1 = b26 ; lower part of measure pulse out
    ;debug
    
    ;if arg1 = main_last then
    ;	goto main
	;endif
    ;main_last = main_last - 1
    ;if arg1 = main_last then
    ;	goto main
    ;endif
    ;main_last = main_last + 2
    ;if arg1 = main_last then
    ;	goto main
    ;endif
    
    ;main_last = arg1
    
    ;gosub display_number
    
    goto main
	;gosub display_hello
    ;goto main
    end

measure_pulse:
	pulsin KEYBD_IN, 1, w0 ; arg1 + arg2
    return
    
; Segment layout:
;  A
; F B
;  G 
; E C
;  DH
;
; 0bHGFEDCBA

symbol DELAY = 500

display_hello:
	; h
    ; 0111 0100
    arg1 = 116
    gosub shift_out
    
    pause DELAY
    
    ; E
    ; 0111 1001
    arg1 = 121
    gosub shift_out
    
    pause DELAY
    
    ; l
    ; 0011 0000
    arg1 = 48
    gosub shift_out
    
    pause DELAY
    
    ; l
    ; 0011 0000
    arg1 = 48
    gosub shift_out
    
    pause DELAY
    
    ; o
    ; 0101 1100
    arg1 = 92
    gosub shift_out
    
    pause DELAY
    
    ; space
    ; 0000 0000
    arg1 = 0
    gosub shift_out
    
    pause DELAY
    
    return
    
display_number:
	if arg1 > 99 then
    	arg1 = arg1 - 100
    endif
    
    arg2 = arg1
    
    arg1 = arg2 / 10
    gosub display_digit
    
    arg1 = arg2 // 10
    arg2 = 1
    gosub display_digit
    
    return
    
display_digit:
	lookup arg1, (63,6,91,79,102,109,125,7,127,111,119,124,57,94,121,113,61,118,16,30,56,84,92,115,220,80,120,62,110), arg1
    if arg2 = 1 then
    	arg1 = arg1 or %10000000 ; display decimal point
    endif
    	
    gosub shift_out
    return
    
display_letter:
	select case arg1
    	case "A"
        	arg1 = %01110111 
        case "B"
        	arg1 = %01111100
        case "C"
        	arg1 = %00111001
        case "D"
        	arg1 = %01011110
        case "E"
        	arg1 = %01111001
        case "F"
        	arg1 = %01110001
        case "G"
        	arg1 = %00111101 
    endselect
    
    if arg2 = 1 then
    	arg1 = arg1 or %10000000 ; turn on decimal
    endif
    
    gosub shift_out
    return

; the segments are daisy-chained right-to-left
; shift out what you want for the one on the left, then the one on the right to push it over
shift_out:
	shift_out_current_mask = 1
shift_out_loop:
	shift_out_temp = shift_out_current_mask and arg1 ; bitwise and
    if shift_out_temp > 0 then
    	low SHIFT_DATA
    else
    	high SHIFT_DATA
    end if
    
    high SHIFT_CLK
    low SHIFT_CLK
    
    shift_out_current_mask = shift_out_current_mask * 2
    if shift_out_current_mask != 0  then shift_out_loop
    return