On 22 September 2010 16:10, David Duffy (AVD)
<david@audiovisualdevices.com.au> wrote:
> =A0On 22/09/2010 3:16 PM, Scott wrote:
>>> =A0 Up until now, I've only used the older (lower end?) PICs
>> 16F and lower don't have LAT.
>
> You might want to check that. =A0I'm using a 16F1934 and it does indeed
> have LATx registers - 5 of them!
>
>>> I think I understand the difference between PORTx and LATx, but in one
>>> data sheet Microchip show port B being initialised like so:
>>>
>>> BANKSEL =A0 =A0 PORTB
>>> CLRF =A0 =A0 =A0 =A0PORTB
>>> BANKSEL =A0 =A0 LATB
>>> CLRF =A0 =A0 =A0 =A0LATB
>>> BANKSEL =A0 =A0 ANSELB
>>> CLRF =A0 =A0 =A0 =A0ANSELB
>>> BANKSEL =A0 =A0 TRISB
>>> CLRF =A0 =A0 =A0 =A0TRISB
>>>
>>> Why bother clearing TRISB when you would be only writing to LATB anyway=
?
>>> David...
>> TRIS controls the direction of the pin (e.g. input or output).
>> Use PORT when you want to read a digital input.
>> Use LAT when you want to write a digital output.
>>
>
> Yes, I understand this. =A0But why bother clearing PORTx when clearing
> LATx is really clearing the port?
I'm guessing Scott was answering your original Q:

'Why bother clearing TRISB when you would be only writing to LATB anyway?'

You've not restated the Q as:

'But why bother clearing PORTx when clearing LATx is really clearing the po=
rt?'

Which is a completely different Q, (which I don't have an answer for!)

Matt

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