PIC16F684 PIN_C0 wont stay high when set.

[Chris]

Hi All,
I am trying to finish a servo controller routine and noticed the motor gets very twitchy when running at certain speeds.

I isolated the faulty code and recreated the problem with the following snippet:
#include <16F684.h>

#fuses HS,NOWDT,NOPUT,NOMCLR,NOPROTECT,NOBROWNOUT,NOIESO,NOFCMEN,NOCPD
#use delay(clock=20000000)

main()
{
*0x91=0; //clear ANSEL
*0x1F=0; //ADCON0
*0x9F=0; //ADCON1
*0x85=0; //TRISA
*0x87=0; //TRISC
*0x19=0; //CMCON0
*0x16=0; //PWM1CON
while(1)
{
OUTPUT_high ( PIN_C0 );
OUTPUT_high ( PIN_C2 );

}
}

I tried clearing as many registers as possible so they arent configured as somthing else. Have I got them all?

I want this code to set C0 high and C2 high. What I get is C0 creates a high frequency pulse train. It goes high until C2 is set then it goes low until C0 is set high again. C2 stays low and never goes high. Odd?

I have already had advice which highlighted faults in the CCS compiler for the 684 CCP features (which affected the digital pins too) and now suspect either another compiler fault or I havent configured something correctly but I have spent lots of time trying to track down the fault.

I can run the final code perfectly on a PIC16F877 version of the hardware.

Advice appreciated please.

Best Regards

Chris

[PCM programmer]

This question should be re-posted in the General Discussion Forum.
You posted it in the Programmers forum by mistake.

[drh]

You need to read the data sheet, DS41202C, page 40.
_________________
David