Description
Problem
The DigitalIn .is_connected() function serves to check if the pin has been connected, that is if the pin has been initialized with a pin value or is a no connection NC value. Currently the implementation is broken and is not populating correctly. It has something to do with how objects are getting passed around, I believe it is because the actual GPIO object is being initialized in the target code and not in the mbed hal code. I believe this is resulting in the value being initialized to 0 instead of to FFFF (which is the NC sentinal), thus resulting in incorrect behavior.
Solution
fix it so this function works. Also consider renaming function to is_initialized() as that makes more sense from a user perspective.
Example
In this example we create two DigitalIn objects, the first one pin is initialized and thus the is_connected() function should return true. The second object, din is not initialized, and thus should return false, however because of schenaniganz in the underlying library it does not actually work as expected and returns true.
#include "mbed.h"
DigitalIn pin(D4);
DigitalIn *din;
int main()
{
pin.mode(PullNone); // PullUp, PullDown, PullNone, OpenDrain
while(1) {
wait(1);
printf("din->is_connected() = %d \r\n",din->is_connected());
printf("pin.is_connected() = %d \r\n",pin.is_connected());
printf("\r\n");
}
}which results in the output of
din->is_connected() = 1
pin.is_connected() = 1
din->is_connected() = 1
pin.is_connected() = 1
din->is_connected() = 1
pin.is_connected() = 1
din->is_connected() = 1
pin.is_connected() = 1