Square Wave Graph

   10 REM Square wave graph
   11 REM plotting program
   12 REM 
  100 REM Set up
  101 REM 
  110 PAPER 0: INK 6: BORDER 0: CLS 
  120 PRINT "VOLTS = ": FOR x=1 TO 6: PRINT AT x*3,0;6-x: NEXT x
  130 INK 3: PLOT 7,151: DRAW 0,-120: DRAW 247,0: INK 6
  140 PRINT AT 1,17;"Square Wave"
  150 DIM a$(9)
  200 REM 
  201 REM Plotting Loop
  202 REM 
  210 FOR x=0 TO 400
  211 REM 
  220 REM Calculate volts
  221 REM 
  230 LET volts=2.5+10*SIN (x/40)
  240 IF volts>5 THEN LET volts=5
  250 IF volts<0 THEN LET volts=0
  300 REM 
  301 REM Plot values
  302 REM 
  310 PLOT INK 7;8+(24*x/40),32+volts*24
  320 REM 
  321 REM Print values
  322 REM 
  330 PRINT AT 0,7;volts;a$
  340 PRINT AT 21,15;x/40;a$
  350 REM 
  351 REM End loop
  352 REM 
  360 NEXT x
  370 STOP