So that the user can explicitly deactivate UART(0) if needed. See
issue #4314.
This introduces some risk to "brick" the device, if the user disables the
REPL without providing an alternative REPL (eg WebREPL), or any way to
reenable it. In such a case the device needs to be erased and
reprogrammed. This seems unavoidable, given the desire to have the option
to use the UART for something other than the REPL.
This patch in effect renames MICROPY_DEBUG_PRINTER_DEST to
MICROPY_DEBUG_PRINTER, moving its default definition from
lib/utils/printf.c to py/mpconfig.h to make it official and documented, and
makes this macro a pointer rather than the actual mp_print_t struct. This
is done to get consistency with MICROPY_ERROR_PRINTER, and provide this
macro for use outside just lib/utils/printf.c.
Ports are updated to use the new macro name.
machine.Timer now takes a new argument in its constructor (or init method):
tick_hz which specified the units for the period argument. The period of
the timer in seconds is: period/tick_hz.
For backwards compatibility tick_hz defaults to 1000. If the user wants to
specify the period (numerator) in microseconds then tick_hz can be set to
1000000. The user can also specify a period of an arbitrary number of
cycles of an arbitrary frequency using these two arguments.
An additional freq argument has been added to allow frequencies to be
specified directly in Hertz. This supports floating point values when
available.
This patch makes it so that UART(0) can by dynamically attached to and
detached from the REPL by using the uos.dupterm function. Since WebREPL
uses dupterm slot 0 the UART uses dupterm slot 1 (a slot which is newly
introduced by this patch). UART(0) must now be attached manually in
boot.py (or otherwise) and inisetup.py is changed to provide code to do
this. For example, to attach use:
import uos, machine
uart = machine.UART(0, 115200)
uos.dupterm(uart, 1)
and to detach use:
uos.dupterm(None, 1)
When attached, all incoming chars on UART(0) go straight to stdin so
uart.read() will always return None. Use sys.stdin.read() if it's needed
to read characters from the UART(0) while it's also used for the REPL (or
detach, read, then reattach). When detached the UART(0) can be used for
other purposes.
If there are no objects in any of the dupterm slots when the REPL is
started (on hard or soft reset) then UART(0) is automatically attached.
Without this, the only way to recover a board without a REPL would be to
completely erase and reflash (which would install the default boot.py which
attaches the REPL).
Disabling this saves around 6000 bytes of code space and gets the 512k
build fitting in the available flash again (it increased lately due to an
increase in the size of the ESP8266 SDK).
The uos.dupterm() signature and behaviour is updated to reflect the latest
enhancements in the docs. It has minor backwards incompatibility in that
it no longer accepts zero arguments.
The dupterm_rx helper function is moved from esp8266 to extmod and
generalised to support multiple dupterm slots.
A port can specify multiple slots by defining the MICROPY_PY_OS_DUPTERM
config macro to an integer, being the number of slots it wants to have;
0 means to disable the dupterm feature altogether.
The unix and esp8266 ports are updated to work with the new interface and
are otherwise unchanged with respect to functionality.
Header files that are considered internal to the py core and should not
normally be included directly are:
py/nlr.h - internal nlr configuration and declarations
py/bc0.h - contains bytecode macro definitions
py/runtime0.h - contains basic runtime enums
Instead, the top-level header files to include are one of:
py/obj.h - includes runtime0.h and defines everything to use the
mp_obj_t type
py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
and defines everything to use the general runtime support functions
Additional, specific headers (eg py/objlist.h) can be included if needed.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
