Addressing multiple PORTs using one Variable

[richard]

    PORTA.0[X]   = 1   ' No! Makes a blink in the scope and then stays LOW

works ok in your loop for me, although it is much slower , period goes from 3uS to 13uS

[Ioannis]

"Makes a blink in the scope and then stays LOW"

It will return to low if:

1. you force it somewhere in the program to return to low

2. you PIC is reset for some reason (Watchdog maybe, decoupling cap missing, etc).

Other than these, I see no way to behave like this.

Ioannis

[flotulopex]

1. you force it somewhere in the program to return to low

2. you PIC is reset for some reason (Watchdog maybe, decoupling cap missing, etc).

All the code and fuses settings are here.

I soldered the crystal directly on the µC's pins, a 100nF cap is there...

although it is much slower , period goes from 3uS to 13uS

Strange. The pulse should be 800ns (nano seconds).


Okay, I'll give it a try with another 16F690...

[HenrikOlsson]

Not sure I understand....
Are you saying that this code works:

MAIN:
    PORTA.0[23]  = 1   ' OK but useless
    ASM
      nop
      nop
      nop
    ENDASM
    
    PORTC.7 = 0         ' have this syntax for tests only here
        ASM
            nop
        ENDASM
        
    GOTO MAIN
END

And this isn't:

X VAR BYTE
X = 23
MAIN:
    PORTA.0[X]   = 1   ' No! Makes a blink in the scope and then stays LOW
    ASM
      nop
      nop
      nop
    ENDASM
    
    PORTC.7 = 0         ' have this syntax for tests only here
    ASM
      nop
    ENDASM
        
    GOTO MAIN
END

The 16F690 has an ADC and comparators.
Many of the pins are analog. I don't see you setting them to digital mode. PortC.7 is, however, not one of the analog pins but since you're trying to "index" pins with a variable I suspect PortC.7 isn't the only pin you want to use.

/Henrik.

[flotulopex]

Yes Henrik, you might be right.

Keen to keep the code snippet very (maybe too) short here, I removed all others register settings I have set in the original code.

I'll give it also a try...when I'm back from office.