When `MOST_RECENT_PORT` is set to `1`, the most recently added USB
serial is selected. This is a crude but surprisingly effective filter.
However, for the CC2560-Launchpad this doesn't work, as it provides
two USB serials. The first USB serial interface is the targeted UART
bridge and the second controls the debugger. Since the second is added
a tiny fraction after the first, this reliably selects the wrong
interface. Allowing the board to filter USB serials first can avoid
this issue.
This is also useful as e.g. an STM Nucleo board can easily be told
apart from an `samr21-xpro` or an nRF52840dk using such filters.
Add `esp32-ci` and `esp8266-ci` as external boards to cover optional modules by CI compilation:
- examples/gnrc_networking to cover ESP32/ESP8266 `esp_wifi_ap`
- examples/gnrc_minimal to cover ESP32 `esp_wifi_enterprise`
Using the nrf51xx_peripherals.h vendor header unifies the nrf51
code tree with the nrf52 implementation. It is needed to
prevent build errors with the optional nrfx package.
Placing the SUIT key in the RIOT repository folder is dangerous as
a repo checkout is by most people considered a volatile location.
Since all important files are stored in git, deleting the entire folder
or it's contents is not an uncommon cleanup operation.
If the user is at that point unaware that SUIT key material is stored
in that folder, that key will then be lost.
Another workflow may involve multiple checkouts of the RIOT repository
to multiple folders to work on several features at the same time, or for
easy cross-referencing or splitting of off features from an integration
into a feature branch.
In that case each checkout would use it's own incompatible SUIT key.
To avoid all these pitfalls, place the SUIT keys outside the RIOT
repository in the $XDG_DATA_HOME directory.
DEFAULT_MODULEs declared in defaultmodules_regular.inc.mk MAY only be
disabled at APPLICATION level or in BOARD/CPU Makefile.default. These
modules MAY have complex dependencies themselfs.
DEFAULT_MODULEs declared in defaultmodules_no_recursive_deps.inc.mk MAY be disabled
during dependency resolution. The MUST only have dependencies against
modules with no dependencies themselfs, and these dependencies must
be defined in makefiles/defaultmodules._deps.inc.mk
