Lpc2000

OK, I am confused. I'm using the Nohau LPC210x eval board and for some 
reason I can't set GPIO's P0.2 and P0.3 as high output.

If I set IODIR = 0x0000000F
and then IOSET = 0x0000000F

I get IOPIN 0x00000003 (which is reflected on the external pins).

PINSEL0 and PINSEL1 are both 0, so as I understand it all pins should 
be GPIO's. I have done nothing to enable I2C (although given PINSEL0 it 
shouldn't do anything even if I had). I've also tried this at reset and 
gotten the same result.

I can set P0.0 and 0.1 (and any other gpio I've tried). I'd use 
different pins except that they've wired JTAG into the primary port so 
this means I lose P0.17-31 (there's no way to turn off the trace 
interface correct?).

What am I missing here? Do I just need more coffee?

Thanks!

Shannon

Shannon Holland wrote:

> OK, I am confused. I'm using the Nohau LPC210x eval board and for some 
> reason I can't set GPIO's P0.2 and P0.3 as high output.

Shannon,

One of the functions assignable to P0.2 and P0.3 is that of the I2C 
clock and data.  Per the I2C standard, these have to be open-drain 
outputs, so the LPC21xx implements them as such.  This limitation still 
applies when they are used as GPIOs.

Regards,
Ryan

Ugh, and I even knew that - hate wasting time on stupid mistakes! 
Clearly I need more coffee or beer or both.

Thanks much!

Shannon

On May 28, 2004, at 11:16 AM, MaxStream - Ryan Bedwell wrote:

> Shannon Holland wrote:
>
>> OK, I am confused. I'm using the Nohau LPC210x eval board and for some
>> reason I can't set GPIO's P0.2 and P0.3 as high output.
>
> Shannon,
>
> One of the functions assignable to P0.2 and P0.3 is that of the I2C
> clock and data.  Per the I2C standard, these have to be open-drain
> outputs, so the LPC21xx implements them as such.  This limitation still
> applies when they are used as GPIOs.
>
> Regards,
> Ryan
>
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