LPC1517 pin configuration issue

[lpcware]

Content originally posted in LPCWare by lucamini on Fri Oct 03 01:43:13 MST 2014
I have to configure in the LPC1517 48 pin package, PIO0_22 and PIO0_23 as gpio output, but when I drive to high such pins I find a low level (the pin is floating in the application).

The configuration I used was:

Chip_IOCON_PinMuxSet(LPC_IOCON, 0, 22, IOCON_FUNC0 | IOCON_MODE_INACT | IOCON_DIGMODE_EN);
Chip_IOCON_PinMuxSet(LPC_IOCON, 0, 23, IOCON_FUNC0 | IOCON_MODE_INACT | IOCON_DIGMODE_EN);

and

Chip_GPIO_SetPinDIROutput(LPC_GPIO, 0, 22);
Chip_GPIO_SetPinDIROutput(LPC_GPIO, 0, 23);

What's wrong?

Thanks in advance
Luca

[lpcware]

Content originally posted in LPCWare by mc on Fri Oct 03 09:53:18 MST 2014
Hi lucamini ,
As LabRat explained these pins are true Open drain pins. You will need external pull up.
I recommend you to read pages 110-112/759 and 116/759 of UM10736 Rev. 1.1 — 3 March 2014  to check IO configuration.
http://www.nxp.com/documents/user_manual/UM10736.pdf

[lpcware]

Content originally posted in LPCWare by LabRat on Fri Oct 03 01:52:39 MST 2014

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Quote: lucamini
What's wrong?

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Nothing  :)  (Except you are not reading datasheets / user manuals...)

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Quote:
The I2C-bus functions are fixed-pin functions and must be enabled through the switch
matrix on the [color=#f00]open-drain pins PIO0_22 and PIO0_23[/color].

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