And shouldn't the PEIE bit in INTCON be set also?  Not sure of that one=20
without the datasheet in front of me.
BB

William Bross wrote:

>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:
>
> =20
>
>>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 perio=
d.
>>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
>>
>
> =20
>

--=20
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