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jake1272
Joined: 15 Mar 2021
Posts: 37
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| Digital Capture and PWM Control |
 Posted: Mon Apr 05, 2021 1:56 am |
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How can I implement a code to input a frequency value via RS232 and set the output to it?
Here is my attempt.
| Code: | #include <16F1847.h>
#fuses INTRC_IO,NOWDT,NOPROTECT, MCLR, NOLVP
#use delay(clock=8000000)
//#USE PWM(FREQUENCY=25000,DUTY=50,OUTPUT=PIN_B3) //Configure initial PWM signal
#use RS232(baud=9600, UART1) //RS232 on Pin B1 and Pin B2
//Oscilloscope on CCP pin B3
//float freq,
float TMR2count;
unsigned int16 duty;
void SET_SIGNAL(){
setup_timer_2(T2_DIV_BY_16,TMR2count,1); //Setup Timer2 with calculated counr from input frequency from RS232
setup_ccp1(CCP_PWM); //Configure CCP3 for PWM
duty = 500;
set_pwm1_duty(duty);
}
void main(){
float freq;
//delay_ms(200);
while(1){
printf("\nWhat is your frequency?\n");
scanf("%f",&freq);
freq = getc();
TMR2count=((1/(freq*(4/8000000)*16))-1);
SET_SIGNAL();
}
}
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temtronic
Joined: 01 Jul 2010
Posts: 9097
Location: Greensville,Ontario
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| Posted: Mon Apr 05, 2021 5:18 am |
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Some problems I see...
1) TMR2count cannot be a float.
2) 'ERROR' has to be added to the #USE RS232( ...options....)
3) Some form of range checking of the 'desired frequency' needs to be added.
1 and 2 are easy fixes.. #3 depends upon what the datasheet says are valid numbers, based upon clock frequency and timer setups.
4) Not too sure what 'freq=getc' is supposed to do. |
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jake1272
Joined: 15 Mar 2021
Posts: 37
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| Posted: Mon Apr 05, 2021 5:46 am |
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Following your instructions.
Here is my second attempt
| Code: | #include <16F1847.h>
#fuses INTRC_IO,NOWDT,NOPROTECT, MCLR, NOLVP
#use delay(clock=8000000)
//#USE PWM(FREQUENCY=25000,DUTY=50,OUTPUT=PIN_B3) //Configure initial PWM signal
#use RS232(baud=9600, UART1,Errors) //RS232 on Pin B1 and Pin B2
//Oscilloscope on CCP pin B3
//float freq,
void SET_SIGNAL();
float Getfreq;
//int TMR2count;
float TMR;
void main(){
while(1){
delay_ms(200);
printf("\nWhat is your frequency?\n");
if (scanf("%f",&Getfreq)){
printf("\r\nFrequency is: %f",Getfreq);
TMR =(1.0/(Getfreq*(4.0/8000000.0)*16.0))-1.0;
if (TMR>255) TMR=255;
SET_SIGNAL();
}
SET_SIGNAL();
}
}
void SET_SIGNAL(){
unsigned int16 duty;
int TMR2count=TMR;
setup_ccp1(CCP_PWM); //Configure CCP1 for PWM
setup_timer_2(T2_DIV_BY_16,TMR2count,1); //Setup Timer2 with calculated counr from input frequency from RS232
duty = 500;
set_pwm1_duty(duty);
} |
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