py/mphal.h contains declarations for generic mp_hal_XXX functions, such
as stdio and delay/ticks, which ports should provide definitions for. A
port will also provide mphalport.h with further HAL declarations.
This prevents the loss of RTC time when exiting from standby mode, since
the RTC is paused while it is being re-inited and this loses about 120ms.
Thanks to @chuckbook for the patch.
This file is actually port-generic and should be moved out of stmhal/ .
Other ports already use it, and thus it should use mp_hal_ticks_ms()
right away.
These MPHAL functions are intended to replace previously used HAL_Delay(),
HAL_GetTick() to provide better naming and MPHAL separation (they are
fully equivalent otherwise).
Also, refactor extmod/modlwip to use them.
Scenario: module1 depends on some common file from lib/, so specifies it
in its SRC_MOD, and the same situation with module2, then common file
from lib/ eventually ends up listed twice in $(OBJ), which leads to link
errors.
Make is equipped to deal with such situation easily, quoting the manual:
"The value of $^ omits duplicate prerequisites, while $+ retains them and
preserves their order." So, just use $^ consistently in all link targets.
Instead of return 0, which means EOF. There's no good way to detect EOF on
continuously active bus like UART, and treat timeout as just temporary
unvailability of data. .read() method of UART object will return None in
this case (instead of 0, which again measn EOF). This is fully compliant
with unix port.