Hi

I'm using a 16F627 programmed with PICC Lite as part of a
R/C speed controller for a friend. I'm using the internal
oscillator, an LED+resistor so that I can see if the thing's
working and a 555 to simulate the output from the receiver.
Other than a battery, that's the complete hardware.

My configuration word is 0x3F19: BOD, MCLR, LVP & all timers
disabled. INTRC with clock out.

The code seemed to be progressing nicely, when I came across
a peculiar problem: the output PWM signal was going
"bonkers".

After some thinking and experimenting, I added the two lines
(marked /** 1 **/) to generate 1 single 1us pulse before the
main loop. As I suspected, this pulse is emitted more than
the once it should be (but read on...).

After more experimentation, I discovered that if the code
between /** 2 **/ and /** 3 **/ is present, I get multiple
resets, and it's absent, I do not.

Two different F627's give the same results (which are
repeatable).

Looking at the generated assembler (included below the C
program), I cannot see anything wrong and I would appreciate
any advice you may have.

Thanks for reading.

===Relevant parts of the C program===

|#include <pic.h>
|
|#define byte unsigned char
|
|#define readbit(PORT, BIT)     ((PORT) &   (1<<(BIT)))
|#define setbit(PORT, BIT)      ((PORT) |=  (1<<(BIT)))
|#define clearbit(PORT, BIT)    ((PORT) &= ~(1<<(BIT)))
|#define flipbit(PORT, BIT)     ((PORT) ^=  (1<<(BIT)))
|
|//PORTB bits
|
|#define PULSIN         0       // servo pulses in
|#define FLASHOUT       1       // regular pulses (approx 0.7Hz)
|#define INITPULSE      2       // pulses once during init
|#define PWMOUT         3       // PWM out
|
|void main(void)
|{
|       byte flasher = 0;       // count input pulses
|
|       // setup ports
|
|       PORTA = PORTB = 0;
|       TRISA = TRISB = 0;
|       setbit(TRISB, PULSIN);
|
|       // single pulse during init only
|
|       setbit(PORTB, INITPULSE); /** 1 **/
|       clearbit(PORTB, INITPULSE);
|
|       // here we go!
|
|       for (  ;  ;  )
|       {
|/** 2 **/
|               if (flasher++ >= 30)
|               {
|                       flipbit(PORTB, FLASHOUT);
|                       flasher = 0;
|               }
|/** 3 **/
|       }
|}

===Assembler generated===

|       INCF    desired, 1
|       DECF    desired, 0
|       MOVWF   btemp
|       MOVLW   0x1E
|       SUBWF   btemp, 0
|       BTFSS   STATUS, 0
|       GOTO    0x3AE
|       MOVLW   2
|       XORWF   PORTB, 1
|       CLRF    desired
|0x3AE:
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