Lpc2000

When port0.3 is set as output, when writing '0' to that bit the ouput 
goes '0', but, when writing '1' it seems that it becomes either input 
or tristate so it voltage looks floating.

Anyone encountered such problem?

Thanks

Sam Pr

Forgot to say that i'm using the LPC2138



--- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@...> wrote:
>
> When port0.3 is set as output, when writing '0' to that bit the 
ouput 
> goes '0', but, when writing '1' it seems that it becomes either 
input 

> or tristate so it voltage looks floating.
> 
> Anyone encountered such problem?
> 
> Thanks
> 
> Sam Pr
>

Hi,

  Open collector output for the I2C.

regards,
Charles

--- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@...> wrote:

>
> Forgot to say that i'm using the LPC2138
> 
> 
> 
> --- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@> wrote:
> >
> > When port0.3 is set as output, when writing '0' to that bit the 
> ouput 
> > goes '0', but, when writing '1' it seems that it becomes either 
> input 
> > or tristate so it voltage looks floating.
> > 
> > Anyone encountered such problem?
> > 
> > Thanks
> > 
> > Sam Pr
> >
>

P0.3 requires an external pullup resister. *** P0.2 also requires the 
pullup.

Mike

[Non-text portions of this message have been removed]

Quoting sam_pr <sam_pr@...>:

> When port0.3 is set as output, when writing '0' to that bit the ouput
> goes '0', but, when writing '1' it seems that it becomes either input
> or tristate so it voltage looks floating.

Isn't that one of the IIC I/Os?  See
http://www.open-research.org.uk/ARMuC/LPC2100Tips.html

Robert

Hello,

I know it has the abilty of I2C but I have configured it to GPIO, in 
this case it is supposed to give 'real' '1' or am I wrong.

Sam


--- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@...> wrote:
>
> When port0.3 is set as output, when writing '0' to that bit the 
ouput 
> goes '0', but, when writing '1' it seems that it becomes either 
input 

> or tristate so it voltage looks floating.
> 
> Anyone encountered such problem?
> 
> Thanks
> 
> Sam Pr
>

It is an open collector even if you use it as simple GPIO.
(Same problem occurred to me...)

Carlo

--- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@...> wrote:

>
> Hello,
> 
> I know it has the abilty of I2C but I have configured it to GPIO, in 
> this case it is supposed to give 'real' '1' or am I wrong.
> 
> Sam
> 
> 
> --- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@> wrote:
> >
> > When port0.3 is set as output, when writing '0' to that bit the 
> ouput 
> > goes '0', but, when writing '1' it seems that it becomes either 
> input 
> > or tristate so it voltage looks floating.
> > 
> > Anyone encountered such problem?
> > 
> > Thanks
> > 
> > Sam Pr
> >
>

Thank you,

Finally found the mystery, I got a reply from PHILIPS support.

The pin description in the user manual and in the data sheet are 
different...  and I, ufortunately, used the user manual.

One should compare these two manuals while designing.

Sam

--- In lpc2000@yahoogroups.com, "sam_pr" <sam_pr@...> wrote:
>
> When port0.3 is set as output, when writing '0' to that bit the 
ouput 
> goes '0', but, when writing '1' it seems that it becomes either 
input 

> or tristate so it voltage looks floating.
> 
> Anyone encountered such problem?
> 
> Thanks
> 
> Sam Pr
>