Code on 16F877:

Code:
#CONFIG
    __config _HS_OSC & _WDT_OFF & _WRT_OFF & _BOREN_ON & _LVP_OFF  & _CPD_OFF & _PWRTE_ON & _DEBUG_OFF
#ENDCONFIG

DEFINE  OSC 20

INCLUDE "ALLDIGITAL.pbp"        ; Set all pins as digital

TRISD = %00000000
PORTD = %00000000

PAUSE   1000      

START:  PORTD = %10101010
        PAUSE   1000      
        PORTD = %01010101
        PAUSE   1000      

        GOTO    START
Finish: end

Code on 18F4550:

Code:
#CONFIG
    CONFIG    PLLDIV=5, CPUDIV=OSC1_PLL2, USBDIV=2, FOSC=HSPLL_HS
    CONFIG    PWRT=ON, BOR=ON, BORV=1, VREGEN=ON, WDT=OFF
    CONFIG    CCP2MX=ON, PBADEN=OFF, LPT1OSC=OFF, MCLRE=ON
    CONFIG    STVREN=ON, LVP=OFF, ICPRT=OFF, XINST=OFF
#ENDCONFIG

DEFINE OSC 48

INCLUDE "ALLDIGITAL.pbp"        ; Set all pins as digital

TRISD = %00000000
PORTD = %00000000

PAUSE   1000      

START:  PORTD = %10101010
        PAUSE   1000      
        PORTD = %01010101
        PAUSE   1000      

        GOTO    START
Finish: end

Close-up of jumpers on Lab-X1:

Name: Blinky 16F877 vs 18F4550.jpg Views: 2722 Size: 49.4 KB


Lab-X1 oscillator jumpers:

Name: Lab X1 osc settings.png Views: 2583 Size: 25.8 KB


The only difference between the 2 MCUs are the CONFIG and DEFINE OSC statements.


I'm at a loss to explain what I'm doing wrong here. Whatever I'm doing wrong, I've been doing it for a very long time.

Robert
I can't see the forest with all those trees standing in the way.