Sound generation, sound library...

Audio signals are often used when it is necessary to call the user’s attention to do something, to confirm that one of the push buttons is pressed, to warn that minimum or maximum values are reached etc. It can be just a ‘beep’ signal as well as longer or shorter melodies. This example demonstrates how to generate a sound using functions belonging to the Sound library. In adition to these functions, the Button function is also used for testing push buttons.

'Header******************************************************
program example_13 ' Program name

sub procedure Tone1()
 Sound_Play(659, 250) ' Frequency = 659Hz, duration = 250ms
end sub

sub procedure Tone2()
 Sound_Play(698, 250) ' Frequency = 698Hz, duration = 250ms
end sub

sub procedure Tone3()
 Sound_Play(784, 250) ' Frequency = 784Hz, duration = 250ms
end sub

sub procedure Melody() ' Play the melody "Yellow house"
 Tone1() Tone2() Tone3() Tone3()
 Tone1() Tone2() Tone3() Tone3()
 Tone1() Tone2() Tone3()
 Tone1() Tone2() Tone3() Tone3()
 Tone1() Tone2() Tone3()
 Tone3() Tone3() Tone2() Tone2() Tone1()
end sub

sub procedure ToneA() ' Tones used in Melody2 function
 Sound_Play( 880, 50)
end sub

sub procedure ToneC()
 Sound_Play(1046, 50)
end sub

sub procedure ToneE()
 Sound_Play(1318, 50)
end sub

sub procedure Melody2() ' Play Melody2
 dim counter as byte
 for counter = 9 to 1 step -1
 ToneA()
 ToneC()
 ToneE()
 next counter
end sub

main: ' Start of program

ANSEL = 0 ' Configure analog pins as digital I/O
ANSELH = 0

C1ON_bit = 0 ' Disable comparators
C2ON_bit = 0

TRISB = 0xF0 ' Configure RB7..RB4 as inputs and RB3 as output

Sound_Init(PORTD, 3)
Sound_Play(880, 5000)

while TRUE ' Endless loop
 if (Button(PORTB,7,1,1)) then ' If PORTB.7 is pressed play Tone1
 Tone1()
 while (RB7_bit <> 0)
 nop ' Wait for the button to be released
 wend
 end if

 if (Button(PORTB,6,1,1)) then ' If PORTB.6 is pressed play Tone1
 Tone2()
 while (RB6_bit <> 0)
 nop ' Wait for the button to be released
 wend
 end if

 if (Button(PORTB,5,1,1)) then ' If PORTB.5 is pressed play Tone1
 Melody2()
 while (RB5_bit <> 0)
 nop ' Wait for the button to be released
 wend
 end if

 if (Button(PORTB,4,1,1)) then ' If PORTB.4 is pressed play Tone1
 Melody()
 while (RB4_bit <> 0)
 nop ' Wait for the button to be released
 wend
 end if
wend

end. ' End of program

In order to make this example work properly, it is necessary to check the following libraries in the Library Manager prior to compiling:

• Button
• Sound