Lpc2000

If the pin of P0.14 keep low from powerup,the user code cann't be 
execute?then this pin cann't be used as a general I/O?

--- In lpc2000@yahoogroups.com, "macrowall" <macrowall@y...> wrote:
> If the pin of P0.14 keep low from powerup,the user code cann't be 
> execute?then this pin cann't be used as a general I/O?

Because of this, P0.14 cannot be used as generally as the other 
I/Os.  You can still use it as an output, provided the thing it is 
controlling doesn't mind being pulled low at power-on when you want 
to enter the bootloader.

Karl

Hello Karl,

there are two options for Philips tp realize this function, getting
into the bbotloader.
1. a dedicated pin, no discussions, no problems, it is up to any user
to treat P0.14 as such dedicated pin.
2. offer an option to us users to use the pin as (somewhat limited)
I/O-pin.

Personally I prefer the option number 2 

You are right, P0.14 can either be used as output or it can be pulled
high by an external pull-up for regular operation and "overwritten" by
an external signal that drives the pin stronger than the pull-up. In
this case you can use the pin as input too.

In either case whether the pin is used as input or output, we must be
careful because a system that jumps into the bootloader every time is
not very useful ;-)

Cheers, Bob

--- In lpc2000@yahoogroups.com, "Karl Olsen" <kro@p...> wrote:

> --- In lpc2000@yahoogroups.com, "macrowall" <macrowall@y...> wrote:
> > If the pin of P0.14 keep low from powerup,the user code cann't be 
> > execute?then this pin cann't be used as a general I/O?
> 
> Because of this, P0.14 cannot be used as generally as the other 
> I/Os.  You can still use it as an output, provided the thing it is 
> controlling doesn't mind being pulled low at power-on when you want 
> to enter the bootloader.
> 
> Karl