PWM control output problem

[papaonn]

Hi there i have some problem with PWM control,
I am using PIC16F877A microchip.

I have read some articles online and found that there is a PSTRCON register to control the output of PWM, which are P1A, P1B, P1C, & P1D.
however, i compiled my code in MPLAB (HI-TECH C compiler), it gave me an error saying that 'PSTRCON undeclared identifier'.

I have searched thru the internet and found no result about why it gave me undeclared identifier,
I included both <pic.h> & <htc.h> and got no results still.

I am wondering if there is necessary to switch on PSTRCON register,
or there is another way to generates output from PWM,

ALL I want to do is just 'Get some output from PWM signals to drive motors',
can somebody show me the way?

Thanks so much!

Regards,
Daniel.

 

[horace1]

the PIC16F877A does not have a PSTRCON register see
https://ww1.microchip.com/downloads/en/DeviceDoc/39582b.pdf

perhaps you were looking at code for a PIC16F690 which does have a PSTRCON register

do a web search for "PIC16F877A PWM tutorial", you should get plenty of links, e.g.
https://roboticsforyou.blogspot.co.uk/2008/12/ccp-pic16f877a-mikroc-code-tutorials.html

 

[papaonn]

the PIC16F877A does not have a PSTRCON register see
https://ww1.microchip.com/downloads/en/DeviceDoc/39582b.pdf

perhaps you were looking at code for a PIC16F690 which does have a PSTRCON register

do a web search for "PIC16F877A PWM tutorial", you should get plenty of links, e.g.
https://roboticsforyou.blogspot.co.uk/2008/12/ccp-pic16f877a-mikroc-code-tutorials.html

Hi there thank you so much for telling me this,
however the tutorial you given are of microC programming library, i am using Hitech C and hence would not be applicable, still thank you so much =)

 

[horace1]

below is some sample PWM code for a PIC16F917 running on a Microchip PICDEM mechatronics board
**broken link removed**

I think the PIC16F917 uses the same registers as a PIC16F877A

// initialise PWM using Capture Compare PWM Module 2
void PWMinitialise(void)
{
        // assume Fosc uses oscillator 8MHz - call systemInitialise() first
        TRISD2=0;                // set RD2/CCP2 is output
        TRISD7=0;                // set RD7 is output
        PR2=0x3f;                // set PR2 to 31.2 kHz PWM (PWM value will be 8 bits)
        // Configure Capture Compare PWM Module 2
        CCPR2L=0;                // set PWM duty cycle to 0
        CCP2CON=0xC;             // set PWM mode
        TMR2ON=1;                // Turn on Timer 2 PWM
}

// set PWM duty cycle - value between 0 and 100
void PWMcontrol(int dutyCycle)
{
        // get 8 bit value for PWM control at 31.2 kHz PWM
        dutyCycle = (int) (dutyCycle * 255L / 100L);             // get 8 bit value
        RD7=1;                                                   // switch on motor
        // load most significant 6 bits in CCPR2l and least significant two bits in CCP2CON
        CCPR2L=dutyCycle >> 2;                          
        CCP2CON = (CCP2CON & 0xF) + ((dutyCycle << 4) & 0x30);   // set bits 4 and 5
}

 

[papaonn]

sincerely thanks so much for the reply and help,

i've got a new problem right here,
if i am to drive a 12V/5A motor with Hbridge circuit,
how am i going to send my pwm signal from my PIC16F877A which doesn't even provide up to 5V current?
thanks so much.