The driver uses the netdev interface. Due to the limited
capabilities of the transceiver (32 byte FIFO and no source address in the layer2 frame),
it relies on 6LowPAN compression and adds the source address to the frame for that.
CPU_HAS_SRAM_BITBAND can be used to check whether bit-banding is supported for
all of SRAM. With partially supported bit-banding, this feature is more of a
foot gun that a valuable tool.
It is often desiderable to sync on multiple threads, e.g. there can be a controller
thread that waits for `n` worker threads to finish their job.
An inverse semaphore provides an easy primitive to implement this pattern.
After being initialized with a value `n` (in counter mode), a call to `sema_inv_wait()`
will block until each of the `n` threads has called `sema_inv_post()` exactly once.
There are situations where workers might post an event more than once
(unless additional state is introduced).
For this case, the alternative mask mode is provided.
Here the inverse semaphore is initialized with a bit mask, each worker can clear one
or multiple bits with `sema_inv_post_mask()`. A worker can clear it's bit multiple times.
Previously a value of 0 was used for the RSSI to signal that this value is not
present in `gnrc_netif_hdr_t`. However, an RSSI of 0 dBm is legal and even very
plausible data.
This commit defines `GNRC_NETIF_HDR_NO_RSSI` as `INT16_MIN`, which is below the
noise floor in the vacuum of outer space and hence impossible to receive.
For consistency, also GNRC_NETIF_HDR_NO_LQI is defined.
When dumping memory the printed addresses always start with `00000000`.
This can be very confusing and lead to errors.
Allow the user to specify a starting address of the printed memory that
will be used instead.
By introducing a wrapper function, existing users are unaffected.
This adds compile-time options to configure the serial of an USB
peripheral. The serial be autogenerated with a configured number of
bytes. It is also possible to configure a fixed serial string for a
device and disable the autogeneration of the serial.
Update the `atomic_fetch_<OPERATION>_u<WIDTH>()` functions to return the old
value the target contained prior to applying the operation. This makes this
API much more versatile and closer to C11 atomics.
