[Tiva TM4C123] [solved] I'm getting a hard fault when initializing a Pin

[ExXec]

Hey everybody,

I'm currently in the process of porting uPy to the Tiva Launch Pad.

I'm having problems calling
>>> p = Pin('PF2', Pin.OUT)
because the controller goes into the FaultISR(). (Handler for hard faults)
I suspect a nullpointer dereference, but not in my own code, so I have no idea why.
'PF2' is a valid pin name.

The callstack looks like this:

Callstack

uPy1.PNG (18.28 KiB) Viewed 3594 times

And in this line the fault happens:

Line of fault

uPy2.PNG (44.19 KiB) Viewed 3594 times

I cannot step into it.
Here are the values of the local variables right before the call:

Local Variables

uPy3.PNG (7.5 KiB) Viewed 3594 times

Does anybody know why this is happening?

I'm grateful for any ideas!
-ExXec
-------------------------------------------------------------------------
My fork: https://github.com/ExXeptional/micropyt ... ts/tm4c123

[dhylands]

You show that fun_in is 0x00000000 so the address of the routine you're trying to call is the null pointer, which is what's causing the exception and why you can't step into it.

So you need to work backwards and figure out why fun_in is null.

[ExXec]

Ok, I tracked it down to this expression:

Code: Select all

MP_STATE_PORT(pin_class_mapper)

this returns 0x00000000


I copied that part from the stm32 port, so I don't know what this does

[dhylands]

The code only calls that function if pin_class_mapper is not equal to mp_const_none. mp_const_none isn't the value 0x00000000
pin_class_mapper is initialized to mp_const_none in the function pin_init0 which should be called from your main.c as it is here:
https://github.com/micropython/micropyt ... ain.c#L587

[ExXec]

yeah that was the problem, thanks