Don't forget a second delay after setting PortC high, like this:
Code:
LDAA #$FF
STAA DDRC ; Making Port C Output
LDAB #$00 ; Pulling all pins down
STAB PortC
** a delay
LDAB #$FF
STAB PortC
[COLOR="Red"]**another delay[/COLOR]
Without the second delay the LED is on for such a short time you can't see it, much less measure it with a meter.
Also, your code doesn't show it so I'll mention it in case you don't know - a label at the top of that bit of code and a branch to the top of it so it loops. Like this (excuse my ultra-rusty HC11 coding and adjust to suit):
Code:
loop LDAA #$FF
STAA DDRC ; Making Port C Output
LDAB #$00 ; Pulling all pins down
STAB PortC
** a delay
LDAB #$FF
STAB PortC
[COLOR="Red"]**another delay[/COLOR]
bra loop