Removed the legacy FMUv4 define that was activating a nonexistent
pull up and on some HW driving the PPM_IN aka RC_IN aka SPEKTRUM_RX
to VDD.
Also detailed the connections of this pins for the board.
The simplest connection is RC_IN to a timer capture pin
and a UART.
In this case the UART_RX pin and just be left as is.
While the pin can be configured as the PPM_IN (Timer capture)
or as SPEKTRUM_RX_AS_GPIO_OUTPUT to use it as and GPIO to
facilitate binding.
Renamed the macros and defines to be more explicit as to what
Is being done and the sense of the parameters
We need to protect access to the param_values array. This is dynamically
allocated and resized (utarray_reserve() calls realloc). If some thread
was iterating the array while another was resizing the array, the first one
would iterate on a freed array, thus accessing invalid memory.
On NuttX this could lead to hardfaults in rare conditions.
Unfortunately we need to initialize the semaphore on startup, by calling
sem_init(). This adds a param_init() method called by every board/config
that uses the params (at least I think I've found all of them)
boards define BOARD_NAME, so board_name() is not necessary. HW_ARCH was
just a wrapper around board_name().
This patch simplifies to having only one common method px4_board_name().
We don't have C++ unsafe headers (anymore).
I added a test to fix_headers.sh that checks if certain "unsafe"
headers are ONLY included inside a __BEGIN_DECLS ... __END_DECLS
(because after all, they are unsafe), as well as checking that
no other header files are included inside such a block. The rationale
of the latter is that if a file is a C header and it declares
function prototypes (otherwise it doesn't matter) and is sometimes
included outside a __BEGIN_DECLS ... __END_DECLS block (from a C++
source file) then it has to be C++ safe and doesn't ever to be
included from inside such a block; while if a file is a C++ header
then obviously it should never be included from such a block.
fix_headers.sh subsequently found several safe headers to be
included from inside such a block, and those that were (apparently
in the past) unsafe were included only sometimes inside such a
block and often outside it. I had a look at those files and saw
that at least an attempt has been made to make them C++ safe,
but especially because they already are included OFTEN outside
a __BEGIN_DECLS ... __END_DECLS (from C++ source files) the
best decision seems to treat them as safe.
This is not risky: .c files that define such functions still
generate C-linkage for their functions. If a C++ unsafe C header
is included outside a __BEGIN_DECLS ... __END_DECLS block then
the only possible result would be an undefined reference to
a function with C++-linkage that will not exist. Aka, when
something links after this commit, then the commit was correct.
I did build all targets and they all linked.
It makes more sense to set the optimization flags on a platform basis
instead of individually for each module. This allows for different
optimization options for SITL, NuttX, Snapdragon, etc.
David Sidrane