We don't need to read-modify-write the CTRLA register to disable
the UART.
The entire CTRLA register is re-written just a few lines below, so
we can just set it to 0 to disable the UART.
There is also no need to reset the UART since we re-write all config
registers in init.
If a timer triggers while the idle thread is running, previously a stack
overflow was triggered. This commit increases the idle threads stack size if
xtimer is used.
- Added missing wait for TX flush
- Grouped access to the same registers of the Ethernet PHY to reduce accesses.
(The compiler won't optimize accesses to `volatile`, as defined in the C
standard.)
- Add missing `volatile` to DMA descriptor, as memory is also accessed by the
DMA without knowledge of the compiler
- Dropped `__attribute__((packed))` from DMA descriptor
- The DMA descriptor fields need to be aligned on word boundries to
properly function
- The compiler can now more efficiently access the fields (safes ~300 B ROM)
- Moved the DMA descriptor struct and the flags to `periph_cpu.h`
- This allows Doxygen documentation being build for it
- Those types and fields are needed for a future PTP implementation
- Renamed DMA descriptor flags
- They now reflect to which field in the DMA descriptor they refer to, so
that confusion is avoided
- Added documentation to the DMA descriptor and the corresponding flags
The Atmel I2C peripheral supports arbitrary I2C frequencies.
Since the `i2c_speed_t` enum just encodes the raw frequency values,
we can just use them in the peripheral definition.
We just have to remove the switch-case block that will generate an error
for values outside of `i2c_speed_t`.
The available GPIO ports may also differ within a family. Therefore, the vendor definitions GPIO* are used instad of CPU_FAM_STM definitions to determine which ports are available for a certain MCU.
fcntl(fd, F_SETOWN, getpid()); doesn't seem to work on Linux
to get generate a signal when an event on the GPIO fd occurs.
So fall back to the same method as on OS X and call poll() in
a child process.
select() can not listen to POLLPRI events which are used by the
Kernel's GPIO API.
In preparation for that, rewrite async_read() to use poll() instead
of select().
The PendSV interrupt is used to request a scheduling operation. An
interrupt during the idle sleep can re-request the PendSV interrupt,
while the PendSV is still busy scheduling the next thread. This clears
the request after sleep to prevent triggering an extra PendSV interrupt
after the current PendSV handler finished.
