Hi Neil,
I gave it a quick scan and it looks pretty straightforward to me.  Is=20
your port bit set to an output?  Toggling the LAT reg?
Bill


Neil wrote:

>Would appreciate a fresh pair of eye here please, as I must be missing=20
>something very basic.
>
>I'm using Timer4 on a 18F24K22 to generate repeated pulses (C18 v3.46),=20
>but changing the PR4 match value does not seem to have any effect, and=20
>changing the prescale value seems to give odd results. This is a brief=20
>section of what I have...
>
>     T4CON =3D 0b00000101;
>     PR4 =3D 50;
>     PIE5bits.TMR4IE =3D 1;
>     RCONbits.IPEN =3D 0;                // Disable interrupt priorities
>     INTCONbits.GIE =3D 1;
>
>The interrupt service routine...
>     if (PIR5bits.TMR4IF)
>     {
>         ... < Toggle PORT bit here for logic analyzer > ...
>         ... other code here ...
>         PIR5bits.TMR4IF =3D 0;
>     }    // Timer-1 interrupt
>
>With this, I get regular pulses on the logic analyzer.
>Changing PR4 has no effect on the timing.
>Now, if I change T4CON to 0b00001101, nothing changes.  0b00010101=20
>also.  0b00110101 changes the timing though, to double the previous period=
..
>I tried Timer-2 similarly and got the same results.
>Currently I've worked around the issue by using timer-1, but would like=20
>to know what's going on here.
>
>Anyone see what am I missing here?
>
>Cheers,
>-Neil.
>
>
>
>
>
>
> =20
>

--=20
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