AnsweredAssumed Answered

LPC824 SWDIO pin causing issue when set to GPIO Output High

Question asked by Sibin Thomas on Jan 19, 2019
Latest reply on Jan 23, 2019 by jeremyzhou

Hello Everyone,


I am using lpc824 (lpc824M201JDH20J) controller on my custom board and I am trying to set the PO_2 (SWDIO) as GPIO output and P0_3 (SWCLK) as GPIO input pins. My board is powered with 2.8V supply with 47K pullup on the RESET. I have disabled the default function of SWDIO and SWCLK using the switch matrix. I have three leds connected to output pins (P0_1, P0_8 and P0_9). On startup, just after configuring these pins and making P0_2 High, in my while loop i am reading the status of the input pin (P0_3) and toggling the leds.


The problem is when I make PO_2 high and if i reset the controller 2 or 3 times my other pins are not getting configured properly. Like LEDs (P0_8 and P0_9) not going high and low and my input P0_3 is always reading low. but LED P0_1 is working. This issue happens only when i configure P0_2 as output and high and do reset few times. The code is working as expected if my P0_2 is output and low. I am attaching my code where if PO_2 is made high this problem occurs and if P0_2 is low everything works. Is there any problem with the P0_2 (SWDIO) making output and high? Why on several reset the pins are not getting configured properly? Any suggestion would be helpful.