0 REM << RR43-1 >>
1 REM===================================
2 PRINT"[147]         LED DRIVER"
3 REM        RUPERT REPORT #43
4 REM  USE CASSETTE PORT MOTOR OUTPUT
5 REM          TO LIGHT LED
6 REM===================================
10 REM ====== INITIALIZATION ==========
20 DEF FNS(B)=PEEK(M) OR 2^B       :REM  SET BIT B OF LOCATION M
30 DEF FNC(B)=PEEK(M) AND NOT 2^B  :REM  CLEAR BIT B OF LOCATION M
40 M=0 : POKE M,FNS(4) :REM SET DDR FOR  BIT 4 TO BE OUTPUT
50 M=1 : POKE M,FNC(4) :REM CLEAR BIT 4  OF $1 SO $192 IS NOT CLEARED BY IRQ
60 POKE 192,1          :REM SET $192 SO  IRQ DOES NOT TURN MOTOR ON
70 PK=PEEK(1) : L1=PK AND NOT 32 : L0=PK OR 32  :REM  ON AND OFF POKE VALUES
80 DF=.50    :REM DUTY FACTOR = 50%
90 K=2.5 : P=10^K : W1=DF*P : W0=P-W1    :REM INITIAL PERIOD AND PULSE WIDTHS
95 PRINT "[147]" : GOSUB 2000 :REM GRAPH
100 REM ====== MAIN LOOP ===============
110 IF DF=0 THEN 130
120 POKE 1,L1 : FOR N=1 TO W1: NEXT
130 GET A$ : IF A$<>"" THEN GOSUB 1000
140 IF DF=1 THEN 120
150 POKE 1,L0 : FOR N=1 TO W0 : NEXT
160 GET A$ : IF A$<>"" THEN GOSUB 1000
170 GOTO 110
1000 REM ====== KEYBOARD INPUT =========
1010 REM  +  INCREASES FREQUENCY
1020 REM  -  DECREASES FREQUENCY
1030 REM 1-9 = DUTY FACTOR (10 TO 90%)
1040 REM 0 = TOGGLE DUTY FACTOR (0/100%)
1050 REM
1060 IF VAL(A$)>0 THEN DF=0.1*VAL(A$) :  REM  1 TO 9 SELECTED
1070 IF A$="0" THEN DF=-1*(DF=0) :  REM  TOGGLE 0 OR 1
1080 IF A$="-" THEN K=K+.5 :IF K>3.5 THEN K=3.5  : REM INCREASE PERIOD
1090 IF A$="+" THEN K=K-.5 :IF K<.5 THEN K=.5 :REM DECREASE PERIOD/INCREASE FREQ
1100 P=10^K            :REM GET PERIOD
1110 W1=DF*P : W0=P-W1 :REM PULSE WIDTHS
1120 GET A$ : IF A$<>"" THEN 1060 : REM  ANY MORE KEYS?
1130 GOSUB 2000  :REM  DISPLAY BAR GRAPH
1140 RETURN
2000 REM ======= BARGRAPHS =============
2010 PRINT""; : FOR N=1 TO 33 : PRINT"[190]"; : NEXT : PRINT
2020 PRINT"DUTY FACTOR: "; : GOSUB 2100
2025 IF DF=0 THEN PRINT"0";  : GOTO 2040
2030 FOR N=1 TO DF*10+.1 : PRINT "[184][184]"; : NEXT
2040 PRINT : PRINT"FREQUENCY  : "; : GOSUB 2100
2050 FOR N=1 TO 10-3*(K-.5)
2060 PRINT"[185][185]"; : NEXT
2070 RETURN
2100 FOR N=1 TO 20 : PRINT" "; : NEXT
2110 FOR N=1 TO 20 : PRINT"[157]"; : NEXT
2120 RETURN
2990 REM ====== DUTY FACTOR DEMO =======
2991 REM > ADD LINE 99 GOTO 3000
2992 REM > RAPIDLY MOVE THE LED
2993 REM   BACK AND FORTH.
2994 REM > LOOK AT THE RELATIVE WIDTHS
2995 REM   OF LIGHT AND DARK STREAKS
2996 REM   AS THE DUTY FACTOR CHANGES.
2997 REM ===============================
3000 P0=9 : P1=1 : GOSUB 3050
3010 P0=5 : P1=5 : GOSUB 3050
3020 P0=1 : P1=9 : GOSUB 3050
3030 GOTO 3000
3050 FOR CT=1 TO 50
3060 POKE 1,L0 : FOR N=1 TO P0 : NEXT
3070 POKE 1,L1 : FOR N=1 TO P1 : NEXT
3080 NEXT : RETURN