# cant set lpc2138 IO pins

**URL:** <https://community.sparkfun.com/t/cant-set-lpc2138-io-pins/12273>\
**Category:** MicroMod\
**Tags:** arm-lpc\
**Created:** [August 19, 2009, 9:05pm UTC](https://community.sparkfun.com/t/cant-set-lpc2138-io-pins/12273 "2009-08-19T21:05:51Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![crm](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@crm](https://community.sparkfun.com/u/crm)\
**Post date:** [August 19, 2009, 9:05pm UTC](https://community.sparkfun.com/t/cant-set-lpc2138-io-pins/12273/1 "2009-08-19T21:05:51Z")

</div>

hi,

i’m trying to set high the first 16 pins on my board. This is the code i run:

```auto
	PINSEL0 = 0;
	IODIR0 = 0xFFFFFFFF;
	IOSET0 = 0x0000FFFF;
	//IOCLR0 = 0x0000FFFF;

```

the problem is that pin P0.3,P0. 4 and P0.11 are set to 1v after this code is run (the rest of the pins are set on 3.3 V). If i try to set the pins low all is fine. Any ideas about what may be wrong (code, power supply, fried outputs) ?

Edit:

the board that i am using is bought from Olimex. Here’s the schematic:[http://olimex.com/dev/images/ARM/LPC/LP … -B-SCH.gif](http://olimex.com/dev/images/ARM/LPC/LPC-H2138-REV-B-SCH.gif)

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<div class="post-metadata">

**Author:** ![theatrus](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@theatrus](https://community.sparkfun.com/u/theatrus)\
**Post date:** [August 19, 2009, 9:42pm UTC](https://community.sparkfun.com/t/cant-set-lpc2138-io-pins/12273/2 "2009-08-19T21:42:41Z")

</div>

Without seeing a board schematic, it is impossible to tell.

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<div class="post-metadata">

**Author:** ![hsutherl](https://avatars.discourse-cdn.com/v4/letter/h/ee7513/32.png) [@hsutherl](https://community.sparkfun.com/u/hsutherl)\
**Post date:** [August 21, 2009, 11:41pm UTC](https://community.sparkfun.com/t/cant-set-lpc2138-io-pins/12273/3 "2009-08-21T23:41:25Z")

</div>

It’s definitely P0.3, 4, and 11 that are not going to 3.3V?

It might not be a good idea to configure P0.1 and P0.9 as outputs, since those pins are hard-wired to the outputs of U2. I’m surprised that you report an ability to drive those pins.