SETPIN 7, AIN
 SETPIN 8, AIN
 DAC 1, 0
 DAC 2, 0
 PRINT "Left  ";STR$(PIN(7),3,2);" Right ";STR$(PIN(8),3,2)
 DAC 1, 1.65
 DAC 2, 1.65
 PRINT "Left  ";STR$(PIN(7),3,2);" Right ";STR$(PIN(8),3,2)
 DAC 1, 3.3
 DAC 2, 3.3
 PRINT "Left  ";STR$(PIN(7),3,2);" Right ";STR$(PIN(8),3,2)
 DAC 1, 1.65
 DAC 2, 1.65
 do:loop

Left    0.02 Right   0.03
Left    1.66 Right   1.65
Left    3.29 Right   3.29

 OPTION EXPLICIT
 OPTION DEFAULT NONE
 OPTION VCC 3.308
 CONST SAMPLESPERSEC = 10000
 CONST NSAMPLES = 512
 CONST PLOTFREQ = NSAMPLES\512
 DIM INTEGER i, j, imax, imax1, toggle
 DIM FLOAT a(NSAMPLES-1) , b(NSAMPLES-1), a1(NSAMPLES-1), b1(NSAMPLES-1)
 DIM INTEGER c%(179), d%(179),x1(255),x2(255),y1(255),y2(255),y3(255), y4(255)
 DIM FLOAT m(NSAMPLES-1) , mmax , m1(NSAMPLES-1), mmax1,p
 DIM k$
 CLS
 FOR i=0 TO 255
   x1(i)= i*2+194
   x2(i)= i*2+195
 NEXT i
 
 '
 ' First set up some signals using the onboard DAC playing music
 ' connect PA4 to pin 7 and PA5 to pin 8
 '
 ' start the DAC
 '
 'PLAY MP3 "noise"
 'play tone 1000,2000
 'play volume 30,30
 '
 ' convert the signals
 '
 toggle=1
 PAGE WRITE 1
 CLS
 ADC OPEN SAMPLESPERSEC, 7, 8,, adc_done
 ADC START a(), b()
 TEXT 10,40,"Channel 1",,3
 TEXT 10,150,"Frequency 1",,3
 TEXT 10,320,"Channel 2",,3
 TEXT 10,430,"Frequency 2",,3
 DO
   DO
   LOOP WHILE j=0
   j=0
   IF toggle THEN
     ADC START a1(),b1()
     toggle=0
   ELSE
     ADC START a(),b()
     toggle=1
   ENDIF
   
   '
   ' frequency analyse the signals
   '
   IF MM.INFO(VERSION)>=5.0504 THEN
     IF  toggle THEN
       MATH FFT MAGNITUDE b1(),m()
       MATH FFT MAGNITUDE a1(),m1()
     ELSE
       MATH FFT MAGNITUDE b(),m()
       MATH FFT MAGNITUDE a(),m1()
     ENDIF
   ELSE
     IF  toggle THEN
       FFT MAGNITUDE b1(),m()
       FFT MAGNITUDE a1(),m1()
     ELSE
       FFT MAGNITUDE b(),m()
       FFT MAGNITUDE a(),m1()
     ENDIF
   ENDIF
   BOX 194,0,MM.HRES-287,MM.VRES,1,&HFFFFFF,0
   FOR p = 0 TO 512 STEP 102.4
   TEXT 194+p,500,STR$(INT(p*9.765625)),cm
   TEXT 194+p,220,STR$(INT(p*9.765625)),cm
   NEXT p
   '
   ' remove the upper and lower values
   '
   FOR i=1 TO 5
      m(i)= 0
      m1(i) = 0
      m(NSAMPLES\2-i)= 0
      m1(NSAMPLES\2-i) = 0
   NEXT i
   '
   ' find the maximum magnitude of the frequencies
   '
   mmax=0
   mmax1=0
   FOR i=1 TO NSAMPLES\2-1
     IF m(i)>mmax THEN
       mmax=m(i)
       imax=i
     ENDIF
     IF m1(i)>mmax1 THEN
       mmax1=m1(i)
       imax1=i
     ENDIF
   NEXT i
   '
   ' plot the samples
   '
   FOR i=1 TO 255
     IF toggle THEN
       y1(i)=130 - a1(i-1)*40
       y2(i)=130 - a1(i)*40
       y3(i)=410 - b1(i-1)*50
       y4(i)=410 - b1(i)*50
     ELSE
       y1(i)=130 - a(i-1)*40
       y2(i)=130 - a(i)*40
       y3(i)=410 - b(i-1)*50
       y4(i)=410 - b(i)*50
     ENDIF
   NEXT i
   LINE x1(),y1(),x2(),y2(),1,RGB(MAGENTA)
   LINE x1(),y3(),x2(),y4(),1,RGB(GREEN)
   '
   ' plot the frequency analyses
   '
   FOR i=2 TO 255
     y1(i)=470-m((i-1)*PLOTFREQ)/mmax*100
     y2(i)=470 - m(i*PLOTFREQ)/mmax*100
     y3(i)=190-m1((i-1)*PLOTFREQ)/mmax1*100
     y4(i)=190 - m1(i*PLOTFREQ)/mmax1*100
   NEXT i
   LINE x1(),y1(),x2(),y2(),1,RGB(YELLOW)
   LINE x1(),y3(),x2(),y4(),1,RGB(YELLOW)
   TEXT 250,530,STR$(INT(mmax)),cm
   TEXT 250,250,STR$(INT(mmax1)),cm
   PAGE COPY 1 TO 0
   k$ = INKEY$
 LOOP UNTIL k$ <> ""
 IF k$ = "P" OR k$ = "p" THEN SAVE IMAGE "CRO"+MID$(TIME$,1,2)+MID$(TIME$,4,2)+MID$(TIME$,7,2)+".BMP"
 '
 PLAY STOP
 
END
 
SUB adc_done
 j=1
END SUB