This commit adds the ESP32 vendor libraries for WLAN to the BASELIBS variable. This avoids having to define an additional archive group in the LINKGFLAGS variable which contains these vendor libraries and again RIOT module archive files with the symbols that are refered by these vendor libraries.
Measurements show that the time from pin edge until return from
interrupt is reduced from 22 us to 6.1 us for KW41Z running at
41.94 MHz. The measurements used a no-op GPIO callback for testing and
were measured using an external logic analyzer.
cpu.c and startup.c were redundant in most platforms, except for
atmega256rfr2. The common code is now in cpu/atmega_common/cpu.c
and cpu/atmega_common/startup.c. cpu_conf.h is also removed as
it's now in cpu/atmega_common/include thus shared by all atmega
based platforms.
Removes duplicated code for atmega platforms. They were all
basically the same, only with the exception of atmegarfr2,
for which there is an #if statement to use the code in the
same file.
Some ESP32 boards (like my SparkFun ESP32 Thing) have a main clock
crystal that runs at 26MHz, not 40MHz. RIOT appears to assume 40MHz.
The mismatch causes the UART to not sync properly, resulting in
garbage written to the terminal instead of log output.
I’ve added:
* A new board configuration constant ESP32_XTAL_FREQ that defaults
to 40, but can be overridden by a board def or at build time to
force a specific value (i.e. 26).
* Some code spliced into system_clk_init() to check this constant and
call rtc_clk_init() to set the correct frequency.
* A copy of the rtf_clk_init() function from the ESP-IDF sources.
Fixes#10272
Errors flags could not clear making the i2c unusable after error.
This fix removes the error check in start so the error flags can clear and does proper checking for status bits before _bus_check.
The problem seemed to be a pipelining problem of write and read instructions when swapping the context. An isync instruction when returning from a context switch solves the potential pipelining problem.
Reason for the problem was that tast_exit function in thread_arch.c tried to release the thread a second time although it was already released in sched_task_exit. A simple check whether the thread is already released (sched_active_thread == NULL) solved the problem.
Xtensa newlib version requires pthread_setcancelstate as symbol. Therefore, the module pthread was always used, which in turn requires the module xtimer. The xtimer module, however, uses TIMER_DEV(0). Therefore, tests/timers failed for TIMER_DEV(0).
