18F458 and 20MHz osc problem...

Got a problem with an 18F458 and an oscillator higher than 4MHz. Using a PICDEM 2+ protoboard.

Typical blinky LED program:

DEFINE OSC 20
LED VAR PORTB.1
main: HIGH LED
PAUSE 100
LOW LED
PAUSE 100
GOTO main

Works for a 16F877 and a 20MHz osc. Works fine with a 4MHz osc and 18F458, doesn't work with anything higher (including the defined 20MHz).

Using PBPv2.45 and MPLAB v6.5.

Compiling calls PBPW with this line:
Executing: "C:\PIC\PBP\PBPW.EXE" -p18F458 -ampasmwin -oq -c -z -v "test.bas"

I've tried other "Configuration Bits" in MPLAB, but I can't seem to make them stick. Do these do anything for PBP?

Thanks,

Bryan A. Thompson
[email protected]

THat's fast blink led !!!
Did you try programming with HS as oscillator mode in MPLAB??

Yeah, I tried the HS mode. Does the same thing (nothing).

I noticed that HS mode changes back to XT when I compile.

"I noticed that HS mode changes back to XT when I compile."
Of course because XT is the default value if there's no DEFINE OSC_HS included. But what about if you set HS mode when programming ???

which programmer do you use??

OK, got it to work.

Have to change Config Bits to HS after compiing and before programming. Every single time I program, it seems, because compiling changes it back to XT mode.

Is there anything I can change about MPLAB so this doesn't happen?

Bryan

add this line in your program header

@ DEVICE HS_OSC

You must use PM.exe instead of MPASM to compile with this DEVICE line. But in this case i don't know if it will work. PM.exe may not handle this pic18FXXX.

let me know