16F876 : settings for 40Mhz

[mister_e]

It really looks like your programmer don't set the configuration fuses...

i don't have any 18F252, but this one is tested with a 18F452

@ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HSPLL_OSC_1H
    ' Oscillator switch OFF
    ' Use HSPLL (fosc X 4) oscillator  (10mhz here)
    '
@ __CONFIG _CONFIG2L, _BOR_ON_2L & _PWRT_ON_2L & _BORV_45_2L
    ' Brown out reset ON @ 4.5Volts
    ' Power-up timer ON
    '
@ __CONFIG _CONFIG2H, _WDT_ON_2H 
    ' Watch dog timer ON
    '
@ __CONFIG _CONFIG4L, _STVR_ON_4L & _LVP_OFF_4L & _DEBUG_OFF_4L
    ' Stack over/underflow ON
    ' Low Voltage programming OFF
    ' Background debugger OFF
    
Define OSC 40
Start:
      Toggle PORTC.3
      pauseus 100
      goto start

if you change the DEFINE OSC 40 to DEFINE OSC 10 you'll get 25uSec pulses. So PLL is working very well.

Look into your Melabs programmer setings, must have a place to configure programmer options.

If you can't find something like that, send an e-mail to BRUCE from Reynolds Electronics. [email protected] For sure he know the solution for that.