Hi, I haven't used the 2455 but the second __CONFIG line sets the 
oscillator to be 4x the crystal - so you should have DEFINE OSC 40 if 
you are using a 10mhz crystal.  If you aren't using a crystal, you'll 
probably need to change the config settings relating to the oscillator. 
  Now it would seem if this is the problem, you'd be running way to 
fast, not too slow, but I recommend looking these over for any obvious 
problems.

I didn't find any way of changing config settings in a simple manner 
with picbasic pro (but I am by no means an expert), so for my project I 
commented out all the __CONFIG lines in the picbasic pro header file and 
put them in my code.  See: 
http://www.celestialaudio.com/leoProgrammable/index.html
specifically the "library code" link at the bottom.  The settings for 
the board I made are near the top of the file.

Hope it helps-
J



Mark Wotton wrote:

> Hello,
> 
> I'm trying to program a PIC 18F2455 chip. I'm using PicBasic Pro as a
> frontend, MPLab v7.30 for the assembler, and MPLab icd 2 for the
> programmer. A simple testing program to flash a light on and off at 1
> second intervals instead takes 8 seconds:
> 
> ----------------------------------------
> INCLUDE "modedefs.bas"
> 
> define OSC 8
> 
> TRISA=%00000
> TRISB=%00000000
> TRISC=%11111111
> 
> StatusLED	VAR porta.1
> 
> LOOP:
>   high StatusLED
>   pause 1000
>   low StatusLED
>   pause 1000
>   goto LOOP
> ------------------------------------------
> 
> If I change OSC to 4 (or leave it out), the program takes 4 seconds
> per transition, so I initially thought I could just set OSC to 1 and
> be done with it - this wouldn't compile in PicBasic Pro, however,
> giving me the error "Symbol not previously defined (PAUSEUSL)".
> 
> I tried fiddling with some of the constants defined in
> C:\pbp\p18f2455.inc, which the generated assembly included:
> --------------------------------------------
>    INCLUDE "P18F2455.INC"  ; MPASM  Header
>         __CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L &
> _USBDIV_2_1L
>         __CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H
>         __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
>         __CONFIG    _CONFIG3H, _PBADEN_OFF_3H
>         __CONFIG    _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L
> ---------------------------------------------
> 
> Unfortunately, nothing there seemed to have any effect on the timing
> at all. Where do you suggest I look next? I'm at a bit of a loss.
> 
> (It's important that the timing be right for this, as I need to use
> serial comms to load new data at runtime, and SERIN doesn't seem to
> want to work, even when I tried setting the baud rate on the other end
> of the serial to 1200 to compensate.)
> 
> Please let me know if I've missed describing anything important, I'm
> still quite new to PIC programming.
> 
> Cheers,
> Mark
> 
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