RS232 comms - need help with datasheet

[malc-c]

Guys thanks very much for your quick input

I have a hardware file which is then included in the main program. The config settings are

ASM  
  __CONFIG    _CONFIG1H, _OSC_HSPLL_1H
  __CONFIG    _CONFIG2L, _PWRT_ON_2L  
  __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
  __CONFIG    _CONFIG3H, _PBADEN_OFF_3H
  __CONFIG    _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L
ENDASM
DEFINE  OSC 48
'DEFINE  OSC 20  ; config settings 18F4580, 10mhz crystal
ADCON1 = $0F

I don't have a 12 Mhz crystal at the moment, but have tried with a 10Mhz one and the slowness is causing other issues with timings of the PID loops etc, I also don't get any hieroglyphics, but I only get a blank screen with a flashing cursor. So I'll pop down and get a few 12Mhz xtals from a local component suppliers and see what that does, as I really need to run this PIC as fast as it goes, and would like to resolve the comms issue.

Thanks once again for your input,

Sorry noticed I hadn't changed the OSC value

OK tried this with a 10Mhz xtal, but still no joy - and is seems as slow

ASM  
  __CONFIG    _CONFIG1H, _OSC_HSPLL_1H
  __CONFIG    _CONFIG2L, _PWRT_ON_2L  
  __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
  __CONFIG    _CONFIG3H, _PBADEN_OFF_3H
  __CONFIG    _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L
ENDASM
'DEFINE  OSC 48
DEFINE  OSC 40  ; config settings 18F4580, 10mhz crystal
ADCON1 = $0F

Will try the 12mhz xtal when I get one

[malc-c]

I've had no luck with the local electronics store, so have had to order online. Whilst waiting I noticed that the data sheet mentions

RS-232 operation using internal oscillator
block (no external crystal required)

I can't figure out if this is possible irrespective of using an external crystal. If it is possible to use an internal 32mhz internal oscillator for the comms and the external to run the PIC then could someone advise me how to configure the comms definition bits and registers.

Thanks

[mackrackit]

This in the config will set the internal OSC to on with I/O on RA6 and RA&
_OSC_IRCIO67_1H

Set the internal to 8MHz
OSCCON = %01110000 '8 Mhz

PLL the internal
OSCTUNE = %01000000

Then
DEFINE OSC 32

[malc-c]

Dave,

As always, thanks for the quick reply. I'll give it a go and see how it performs