On 10-09-22 01:02 AM, David Duffy (AVD) wrote:
>    Up until now, I've only used the older (lower end?) PICs
>
> I think I understand the difference between PORTx and LATx, but in one
> data sheet Microchip show port B being initialised like so:
>
> BANKSEL     PORTB
> CLRF        PORTB
> BANKSEL     LATB
> CLRF        LATB
> BANKSEL     ANSELB
> CLRF        ANSELB
> BANKSEL     TRISB
> CLRF        TRISB
>
> Why bother clearing TRISB when you would be only writing to LATB anyway?
> David...
>
>   =20

Good point. All writes to PORTx are written to the latch anyway, so clrf=20
PORTx is identical to clrf LATx

The port pin diagrams indicate that fact as well.

Further, all analog pins read as '0', all digital pins read the state of=20
the signal (which for outputs may be a mis-match to the LATx value if=20
you have slow-changing signal lines...).

But, in all cases, clrf PORTx =3D=3D clrf LATx

On the other hand, it's not an error to do it twice... and further,=20
operations other than 'clrf' on PORTx will/may produce a different=20
result than the same operation on LATx... so perhaps it is good practice=20
to treat them 'both' explicitly in the initialization routine...

Rolf
--=20
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