# help with LPC23xx

**URL:** <https://community.sparkfun.com/t/help-with-lpc23xx/5630>\
**Category:** MicroMod\
**Tags:** arm-lpc\
**Created:** [October 29, 2007, 2:03pm UTC](https://community.sparkfun.com/t/help-with-lpc23xx/5630 "2007-10-29T14:03:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![cwang36](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@cwang36](https://community.sparkfun.com/u/cwang36)\
**Post date:** [October 29, 2007, 2:03pm UTC](https://community.sparkfun.com/t/help-with-lpc23xx/5630/1 "2007-10-29T14:03:19Z")

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Hi guys,

I’m a newbie working on a Olimex LPC2378-STK board, I’m trying to get the LCD work, I had problem controlling the LCD\_CS line which is P1.21.

I have set

PINSEL3=0x0003C300; // P1.21 is GPIO

FIO1MASK=0x0;

FIO1DIR=1\<\<21; // P1.21 dir=output

but neither FIO1SET or FIO1CLR works because I always get an 0 in FIO1PIN, what could be the problem?

By the way, I saw the demo code in IAR uses SSP0, what is the difference of SSP0 and SPI0?

Thank you

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<div class="post-metadata">

**Author:** ![busonerd](https://avatars.discourse-cdn.com/v4/letter/b/958977/32.png) [@busonerd](https://community.sparkfun.com/u/busonerd)\
**Post date:** [October 29, 2007, 5:44pm UTC](https://community.sparkfun.com/t/help-with-lpc23xx/5630/2 "2007-10-29T17:44:17Z")

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Have you checked to make sure that the FIO controller is enabled?

By default, the GPIO regs are used [at least on the smaller devices].

Cheers,

–David Carne

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<div class="post-metadata">

**Author:** ![cwang36](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@cwang36](https://community.sparkfun.com/u/cwang36)\
**Post date:** [October 29, 2007, 8:58pm UTC](https://community.sparkfun.com/t/help-with-lpc23xx/5630/3 "2007-10-29T20:58:41Z")

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Thanks! That’s the point!

I have to set Bit 0 in SCS:

0 GPIOM GPIO access mode selection. R/W 0

0 GPIO ports 0 and 1 are accessed via APB addresses in a fashion

compatible with previous LPC2000 devices.

1 High speed GPIO is enabled on ports 0 and 1, accessed via addresses in

the on-chip memory range. This mode includes the port masking feature

described in the GPIO chapter.

before using the FIO feature

Thank you!!