configuring I2C pins(5.2&5.3) as GPIO but not working

[lpcware]

Content originally posted in LPCWare by Iyyappan on Mon Jan 11 23:39:01 MST 2016
Hi,

I am new to LPC1788.I need to use the I2C pins(5.2 & 5.3) as a GPIO on LPC1788 controller as given below.

Pinsel_ConfigPin(5,2,0);
Pinsel_ConfigPin(5,3,0);
GPIO_SetDir(5,(1<<2),1);//configured as output
GPIO_SetDir(5,(1<<2),1);//configured as output

I'm using this pins for External ADC.
while checking the User manual it says,
"For non-I2C operation, these pins remain open-drain and can only drive low,
regardless of how HS and HIDRIVE are set. They would typically be used with an
external pull-up resistor if they are used as outputs unless they are used only to sink
current. Leave HS = 1 and HIDRIVE = 0 (if applicable) to maximize compatibility with
other GPIO pins."

after adding Pull-Up register it remains low.

[lpcware]

Content originally posted in LPCWare by serge on Wed Jan 13 01:08:25 MST 2016
What is the value of the external resistor to VCC? As stated this is a true open-drain output.

As per datasheet:

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Quote:
Open-drain 5 V tolerant digital I/O pad, compatible with I2C-bus 1 MHz specification.
It [u]requires[/u] an external pull-up to provide output functionality.

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[lpcware]

Content originally posted in LPCWare by R2D2 on Tue Jan 12 04:57:49 MST 2016

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Quote: Iyyappan
But it is in always low state only.whether i'm giving high or low the state of the pin is always low...

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Then use the debugger to check PCONP, IOCON and Port settings  :O

[lpcware]

Content originally posted in LPCWare by Iyyappan on Tue Jan 12 04:18:12 MST 2016
hi ,

I need that the pin(5[2]) is always high.But it is in always low state only.whether i'm giving high or low the state of the pin is always low.please help me out with this problem.

[lpcware]

Content originally posted in LPCWare by R2D2 on Tue Jan 12 01:14:44 MST 2016

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Quote: Iyyappan

 PDWN_SET//(5[2]) It is always high

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And what's happening if you switch it 'always low' ?

[lpcware]

Content originally posted in LPCWare by Iyyappan on Tue Jan 12 01:05:41 MST 2016
Hi R2D2,
                thanks for the immediate response.yes.already did it.

   PDWN_CLR//low(5[2])
   Delay(100);
   PDWN_SET//(5[2]) It is always high

but still now I'm having the same response(its low but not going to high)..Is there any other way to make it work??

[lpcware]

Content originally posted in LPCWare by R2D2 on Tue Jan 12 00:04:20 MST 2016
Did you switch P5[2] / P5[3] high or low  :quest: