Summary of Sound frequency For Basic PRO Compiler
This article presents a PIC16F877 microcontroller code snippet to control a speaker via a push button. When the button is pressed, a flag toggles, triggering a sound generation subroutine that outputs a 100Hz tone for 120 milliseconds. The system continuously monitors the button state and uses an 8-bit ADC configuration while setting Port B as output and Port A as input.
Parts used in the PIC16F877 Speaker Control:
- PIC16F877 Microcontroller
- Speaker connected to Port B bit 0
- Push Button Switch connected to Port A bit 0
- 4 MHz Oscillator
@ device pic16f877
define osc 4
define adc_bits 8
main:
trisb =$00
trisa =$ff
adcon1 = 7
speaker var portb.0
sw1 var porta.0
flg_set var bit
speaker =0
flg_set =0
while(1)
if(!sw1) then
pause 150
toggle flg_set
while(!sw1):wend
endif
gosub sounds
pause 10
wend
end
sounds:
if(flg_set)then
pause 10
sound speaker,[100,10]'100 =(1-127 generate frequency 78.74-10 khz )
'10 = constant time 12ms/1 = 120 ms
else
sound speaker,[0,0]
endif
return
- How is the oscillator frequency defined?
The oscillator is defined as 4 MHz using the define osc 4 command. - What are the port configurations?
Port B is set as output (trisb =$00) and Port A is set as input (trisa =$ff). - How does the button press trigger the sound?
Pressing the switch toggles a flag variable which activates the sounds subroutine. - What frequency does the sound generate?
The code generates a frequency of 100 Hz when the flag is set. - How long does the sound last?
The sound duration is calculated as 120 milliseconds based on the time constant. - What happens if the switch is not pressed?
The speaker outputs silence represented by [0,0] in the sound array. - How is debouncing handled in the code?
A 150 millisecond pause is used after detecting the switch press to debounce.
