Thanks to everyone for their advice - someon on the picbasic.co.uk forum advised us to change the OSCCON register, and that seems to have done the trick. Cheers, Mark On 9/4/06, Mark Wotton wrote: > On 9/4/06, Anand Dhuru wrote: > > Why dont you leave out the define, and specify the internal oscillator to > > rule out other variables? > > > > Then see if the circuit behaves as it should. > > Ok, I've tried this, and get the same result as if I set OSC to 4 - > events happen 4 times more slowly than they ought to, rather than 8 > times. > > Currently, the config section of the asm looks like this (I inlined it > from the relevant .inc file) > > INCLUDE "P18F2455.INC" ; MPASM Header > __CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & > _USBDIV_2_1L > __CONFIG _CONFIG1H, _FOSC_INTOSC_XT_1H > __CONFIG _CONFIG2H, _WDT_OFF_2H > __CONFIG _CONFIG3H, _PBADEN_OFF_3H & _LPT1OSC_ON_3H > __CONFIG _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L > > I've tried all the values for _CONFIG1H listed in the header file, but > none of them actually seem to change anything. I'm really stumped at > this point. Have I missed something? Where's the next logical place to > look? > > > Also, for PBP related stuff try posting on > http://www.picbasic.co.uk/forum/ > > ; its a very active forum and has some real sharp sparks as well. > > Thanks, have done so. > > Cheers > Mark > > > ----- Original Message ----- > > From: "Mark Wotton" > > To: "Microcontroller discussion list - Public." > > Sent: Monday, September 04, 2006 3:16 AM > > Subject: Re: [PIC] time-scaling problem with PIC 18F2455 > > > > > > > > > > On 03/09/2006, at 6:28 PM, Anand Dhuru wrote: > > > > > >> You have defined OSC 8; is the crystal actually 8? > > > > > > So my colleague assures me. I'm not using an external crystal - > > > there's a default oscillator on the board, isn't there? > > > (Again, forgive me my naivete, I'm new to this.) > > > > > >> If you dont define this (use the default 4 MHz) does the frequency > > >> double? > > > > > > Yes - as I mentioned, either setting it to 4 or leaving the OSC > > > declaration out gives 4 seconds per transition. > > > > > >> > > >> Also, the LED would be on for 1 second, and off for 1; the cycle > > >> would be 2 > > >> seconds. > > > > > > True: I was imprecise. It's currently on for 8 and off for 8, with a > > > cycle of 16. > > > > > > Mark > > > > > >> Regards, > > >> > > >> Anand > > >> > > >> ----- Original Message ----- > > >> From: "Mark Wotton" > > >> To: > > >> Sent: Sunday, September 03, 2006 7:46 PM > > >> Subject: [PIC] time-scaling problem with PIC 18F2455 > > >> > > >> > > >>> 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 > > >>> > > >>> -- > > >>> A UNIX signature isn't a return address, it's the ASCII equivalent > > >>> of a > > >>> black velvet clown painting. It's a rectangle of carets surrounding a > > >>> quote from a literary giant of weeniedom like Heinlein or Dr. Who. > > >>> -- Chris Maeda > > >>> -- > > >>> http://www.piclist.com PIC/SX FAQ & list archive > > >>> View/change your membership options at > > >>> http://mailman.mit.edu/mailman/listinfo/piclist > > >>> > > >>> > > >>> -- > > >>> No virus found in this incoming message. > > >>> Checked by AVG Free Edition. > > >>> Version: 7.1.405 / Virus Database: 268.11.7/436 - Release Date: 01- > > >>> Sep-06 > > >>> > > >>> > > >> > > >> -- > > >> http://www.piclist.com PIC/SX FAQ & list archive > > >> View/change your membership options at > > >> http://mailman.mit.edu/mailman/listinfo/piclist > > > > > > -- > > > I'm haunted by the freakish size of Nancy Reagan's head > > > No way that thing came with her body. > > > -- Mission of Burma, Nancy Reagan's Head > > > > > > > > > -- > > > http://www.piclist.com PIC/SX FAQ & list archive > > > View/change your membership options at > > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > > > > > -- > > > No virus found in this incoming message. > > > Checked by AVG Free Edition. > > > Version: 7.1.405 / Virus Database: 268.11.7/436 - Release Date: > 01-Sep-06 > > > > > > > -- > > http://www.piclist.com PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > -- > A UNIX signature isn't a return address, it's the ASCII equivalent of a > black velvet clown painting. It's a rectangle of carets surrounding a > quote from a literary giant of weeniedom like Heinlein or Dr. Who. > -- Chris Maeda > -- A UNIX signature isn't a return address, it's the ASCII equivalent of a black velvet clown painting. It's a rectangle of carets surrounding a quote from a literary giant of weeniedom like Heinlein or Dr. Who. -- Chris Maeda -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist