Lpc2000

Hello everyone.
I am having problems with P0.2 and P0.3 pins.
The trouble is that I can't define them as outputs. I have wrote a
small program:

#include <LPC214x.H>
void main(void)
{
   PINSEL0 = 0;
   IODIR0 = 0xFFFC;
   IOPIN0 = 0x00FC;
   PCON = 1;         // IDLE mode
}

When program is executed, on pins P0.4..15 is logical '1', but on
these P0.2 and P0.3 - nothing. I connected a pull-up resistor to Vcc -
pins does not refuse it, so, I think, these two pins works like
inputs. But WHY?

I use KEIL µVision software.

P.S. sorry for my english ;)

---- Original Message ----

From: "blasteriokas" <blasteriokas@...>
To: <lpc2000@yahoogroups.com>
Sent: Saturday, February 11, 2006 11:32 AM
Subject: [lpc2000] Trouble with LPC2148 P0.2 and P0.3 pins

> I am having problems with P0.2 and P0.3 pins.
> The trouble is that I can't define them as outputs. I have wrote a
> small program:
>
> #include <LPC214x.H>
> void main(void)
> {
>    PINSEL0 = 0;
>    IODIR0 = 0xFFFC;
>    IOPIN0 = 0x00FC;
>    PCON = 1;         // IDLE mode
> }
>
> When program is executed, on pins P0.4..15 is logical '1', but on
> these P0.2 and P0.3 - nothing. I connected a pull-up resistor to Vcc -
> pins does not refuse it, so, I think, these two pins works like
> inputs. But WHY?

Read the pin descriptions in the datasheet or manual, including the 
footnotes.  They are open drain.

Karl Olsen

Karl,

I think the reason is that P0.2 and P0.3 are I2C pins and have an 
open drain characteristic. Working as outputs they are able to 
output a strong 0, but a weak 1 only. Let the pullup connected to 
VCC and set the pins to 0 or 1. You should get the correct logic 
levels then.

Regards

Martin
www.arm-emulator.com


--- In lpc2000@yahoogroups.com, "Karl Olsen" <kro@...> wrote:
>
> ---- Original Message ----
> From: "blasteriokas" <blasteriokas@...>
> To: <lpc2000@yahoogroups.com>
> Sent: Saturday, February 11, 2006 11:32 AM
> Subject: [lpc2000] Trouble with LPC2148 P0.2 and P0.3 pins
> 
> > I am having problems with P0.2 and P0.3 pins.
> > The trouble is that I can't define them as outputs. I have wrote 
a
> > small program:
> >
> > #include <LPC214x.H>
> > void main(void)
> > {
> >    PINSEL0 = 0;
> >    IODIR0 = 0xFFFC;
> >    IOPIN0 = 0x00FC;
> >    PCON = 1;         // IDLE mode
> > }
> >
> > When program is executed, on pins P0.4..15 is logical '1', but on
> > these P0.2 and P0.3 - nothing. I connected a pull-up resistor to 
Vcc -
> > pins does not refuse it, so, I think, these two pins works like
> > inputs. But WHY?
> 
> Read the pin descriptions in the datasheet or manual, including 
the 

> footnotes.  They are open drain.
> 
> Karl Olsen
>

--- In lpc2000@yahoogroups.com, "Karl Olsen" <kro@...> wrote:
>
> ---- Original Message ----
> From: "blasteriokas" <blasteriokas@...>
> To: <lpc2000@yahoogroups.com>
> Sent: Saturday, February 11, 2006 11:32 AM
> Subject: [lpc2000] Trouble with LPC2148 P0.2 and P0.3 pins
> 
> > I am having problems with P0.2 and P0.3 pins.
> > The trouble is that I can't define them as outputs. I have wrote a
> > small program:
> >
> > #include <LPC214x.H>
> > void main(void)
> > {
> >    PINSEL0 = 0;
> >    IODIR0 = 0xFFFC;
> >    IOPIN0 = 0x00FC;
> >    PCON = 1;         // IDLE mode
> > }
> >
> > When program is executed, on pins P0.4..15 is logical '1', but on
> > these P0.2 and P0.3 - nothing. I connected a pull-up resistor to Vcc -
> > pins does not refuse it, so, I think, these two pins works like
> > inputs. But WHY?
> 
> Read the pin descriptions in the datasheet or manual, including the 
> footnotes.  They are open drain.
> 
> Karl Olsen
>

Thank you very mutch, atlast my binary clock (RTC test) is working
properly :)

Sarunas