Configuration Bit Option Problem

[Jerry I]

Thanks in advance for any help.

I am using for the first time the PIC18F2320

My problem is I cannot get the crystal to Oscillate with MCLR is high.

I know this chip has many fuses for internal & external oscillator, power modes, oscillator switch modes.

What I am seeing on scope if MCLR is LOW the Oscillator is running. If MCLR is HI (for normal operation) the oscillator starts then stops after approx 1/2 sec. There must me some power mode or oscillator switch mode that disables the oscillator.

WHAT FUSES DO I USE TO DISABLE THIS. I have used the 18F252 with no problems.


MY current Fuses are

#FUSE HS, NOWDT, NOPROTECT, NOLVP, PUT

I know there are other fuses for power modes, oscillator switch modes like IESO, NOIESO, MCLR, NOMCLR, FCMEN, NOFCMEN

Thanks again for any help.
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516315

[PCM programmer]

:=What I am seeing on scope if MCLR is LOW the Oscillator is running. If MCLR is HI (for normal operation) the oscillator starts then stops after approx 1/2 sec. There must me some power mode or oscillator switch mode that disables the oscillator.
-----------------------------------------------------------
This problem could be caused by letting your program
fall through the end of main(). CCS puts a SLEEP instruction
there, and this would cause the oscillator to stop.

Example:

main()
{
printf("Hello World\n\r");


}

The program above will execute and then the oscillator will
stop. That's because it hits the hidden SLEEP instruction
at the end of main(). To prevent this problem, put a "forever"
loop at the end of main(). Example:

main()
{
printf("Hello World\n\r");

while(1);
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516330

[Jerry.I]

This is not an issue of the Pic going to sleep. I have compiled the same program using the device 18F252 and all runs fine.

I still think it can be a problem with the configuration bits.

Thanks.



:=:=What I am seeing on scope if MCLR is LOW the Oscillator is running. If MCLR is HI (for normal operation) the oscillator starts then stops after approx 1/2 sec. There must me some power mode or oscillator switch mode that disables the oscillator.
:=-----------------------------------------------------------
:=This problem could be caused by letting your program
:=fall through the end of main(). CCS puts a SLEEP instruction
:=there, and this would cause the oscillator to stop.
:=
:=Example:
:=
:=main()
:={
:=printf("Hello World\n\r");
:=
:=
:=}
:=
:=The program above will execute and then the oscillator will
:=stop. That's because it hits the hidden SLEEP instruction
:=at the end of main(). To prevent this problem, put a "forever"
:=loop at the end of main(). Example:
:=
:=main()
:={
:=printf("Hello World\n\r");
:=
:=while(1);
:=}
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516331