How to use PIO0_13 and 18 for GPIO

[brant]

Hi,

I am using both the 48 pin and 64 pin version of the LPC1549 in a design and trying to setup PIO0_13 and PIO0_18 for GPIO to control other hardware.  Looking into Board_Init() in LPCOpen I noticed that it is trying to control those two pins and make use of them for UART0 based debug.  So I disabled that code and instead just init the GPIO subsystem instead with  Chip_GPIO_Init(LPC_GPIO);

My main issue is getting PIO0_13 and PIO0_18 unstuck, even when avoiding the Board_Init() code.  I need to use these pins for external hardware.  They seem to be stuck high no matter what I've tried so far. 

I am easily able to change the pin start of other pins such as PIO0_1, PIO0_2, PIO0_7 for example so I don't suspect anything related to the code doing the state change, just something is missing in the configuration allowing those pins to be software controlled like the others.

What am I missing?

Thanks

[brant · Accepted solution]

I was able to make PIO0_13 and PIO0_18 work just fine as GPIO lines.  The answer lies in the UM10736 manual in chapter 8 regarding the SWM. 

The answer lies in the PINASSIGN0 register by putting that register in reset I was able to get those lines to function as GPIOs

//snip

LPC_SWM->PINASSIGN[0] = 0xFFFFFFFF; //reset UART0, to reconfigure pin 13 and 18.

I'm leaving this here for future travelers.  Read chapter 8, know thy chip!

[soledad]

Thank you for your input. 

Regards

Sol