This is an object-oriented approach, where uos is only a proxy for the
methods on the vfs object. Some internals had to be exposed (the STATIC
keyword removed) for this to work.
Fixes#2338.
In current state `mp_get_stream_raise` assumes that `self_in` is an object
and always performs a pointer derefence which may cause a segfault.
This function shall throw an exception whenever `self_in` does not implement
a stream protocol, that includes qstr's and numbers.
fixes#2331
In `btree_seq()`, when `__bt_seq()` gets called with invalid
`flags` argument it will return `RET_ERROR` and it won't
initialize `val`. If field `data` of uninitialized `val`
is passed to `mp_obj_new_bytes()` it causes a segfault.
It turns out that TIM1 and TIM8 have their own Capture/Compare
interrupt vector. For all of the other timers, the capture/compare
interrupt vector is the same as the update vector.
So we need to add handlers for these vectors and enable them
when using capture/compare callbacks.
During testing of this, I also found that passing a channel callback
into the channel constructor would not enable interrupts properly.
I tested using:
```
>>> pyb.Timer(1, freq=4).channel(1, pyb.Timer.OC_TOGGLE, callback=lambda t: print('.', end=''))
```
I tested the above with channels 1, 4, and 8
Radomir Dopieralski
Paul Sokolovsky
Dave Hylands
Damien George
Matt Brejza
Pavol Rusnak
Krzysztof Blazewicz