#include "mbed.h"
 
DigitalIn input5(p5);
DigitalIn input6(p6);

DigitalOut led1(LED1);
DigitalOut led4(LED4);
 
int main() {
  while(1) {
    led1 = input5;
    led4 = input6;
  }
}

I am using the mbed board LPC1768 and have a problem with pins 5 and 6. I think it's an intermittent hardware problem. In my set-up, pin 5 can connect through a 3k resistor to either Vout (+3.3V) or GND. I have the same configuration for pin 6. When I run the following code, both LED 1 and LED4 are illuminated if either pin 5 _or_ pin 6 are pulled up to Vout: <<code>> #include "mbed.h" DigitalIn input5(p5); DigitalIn input6(p6); DigitalOut led1(LED1); DigitalOut led4(LED4); int main() { while(1) { led1 = input5; led4 = input6; } } <</code>> If pin 5 is pulled up to 3.3V through a 3K resistor and pin 6 is left floating, both pin 5 and pin 6 will be at 3V. If pin 5 is pulled up to 3.3V and pin 6 is pulled down to 0V (both through 3K resistors), then the voltage on both pin 5 and pin 6 is 1.5V. This suggests that pin 5 and pin 6 are connected together and the two 3K resistors form a potential divider. The problem is intermittent because sometimes pin 6 seems to work ok for a while as a DigitalIn if pin 5 is left floating Having said all the above, pins 5 amd 6 work independently if they are used as DigitalOut. The rest of the board seems to be working ok. Is there anything that can be done or are pins 5 and 6 damaged?