Merge tag 'v1.8.6' into parse-bytecode

ESP8266 port uses SDK 2.0, has more heap, has support for 512k devices

This release brings some code size reductions to the core as well as
more tests and improved coverage which is now at 94.3%.

The time.ticks_diff(a, b) function has changed: the order of the arguments
has been swapped so that it behaves like "a - b", and it can now return a
negative number if "a" came before "b" (modulo the period of the ticks
functions).

For the ESP8266 port the Espressif SDK has been updated to 2.0.0, the
heap has been increased from 28k to 36k, and there is support for 512k
devices via "make 512k".  upip is included by default as frozen bytecode.
The network module now allows access-point reconnection without WiFi
credentials, and exposes configuration for the station DHCP hostname.  The
DS18B20 driver now handles negative temperatures, and NeoPixel and APA102
drivers handle 4 bytes-per-pixel LEDs.

For the CC3200 port there is now support for loading of precompiled .mpy
files and threading now works properly with interrupts.

A detailed list of changes follows.

py core:
- py.mk: automatically add frozen.c to source list if FROZEN_DIR is defined
- be more specific with MP_DECLARE_CONST_FUN_OBJ macros
- specialise builtin funcs to use separate type for fixed arg count
- {modbuiltins,obj}: use MP_PYTHON_PRINTER where possible
- modbuiltins: add builtin "slice", pointing to existing slice type
- add "delattr" builtin, conditional on MICROPY_CPYTHON_COMPAT
- sequence: fix reverse slicing of lists
- fix null pointer dereference in mpz.c, fix missing va_end in warning.c
- remove asserts that are always true in emitbc.c
- fix wrong assumption that m_renew will not move if shrinking
- change config default so m_malloc0 uses memset if GC not enabled
- add MICROPY_FLOAT_CONST macro for defining float constants
- move frozen bytecode Makefile rules from ports to common mk files
- strip leading dirs from frozen mpy files, so any path can be used

extmod:
- vfs_fat_file: check fatfs f_sync() and f_close() returns for errors
- vfs_fat_file: make file.close() a no-op if file already closed
- utime_mphal: ticks_diff(): switch arg order, return signed value
- utime_mphal: add MP_THREAD_GIL_EXIT/ENTER warppers for sleep functions
- utime_mphal: implement ticks_add(), add to all maintained ports
- utime_mphal: allow ticks functions period be configurable by a port

lib:
- utils/pyhelp.c: use mp_printf() instead of printf()
- utils/pyexec: add mp_hal_set_interrupt_char() prototype
- libm: move Thumb-specific sqrtf function to separate file

drivers:
- add "from micropython import const" when const is used

tools:
- upgrade upip to 1.1.4: fix error on unix when installing to non-existing
  absolute path
- pip-micropython: remove deprecated wrapper tool
- check_code_size.sh: code size validation script for CI
- replace upip tarball with just source file, to make its inclusion as
  frozen modules in multiple ports less magic

tests:
- extmod/vfs_fat: improve VFS test coverage
- basics/builtin_slice: add test for "slice" builtin name
- basics: add test for builtin "delattr"
- extmod/vfs_fat_fsusermount: improve fsusermount test coverage
- extmod/vfs_fat_oldproto: test old block device protocol
- basics/gc1: garbage collector threshold() coverage
- extmod/uhashlib_sha1: coverage for SHA1 algorithm
- extmod/uhashlib_sha256: rename sha256.py test
- btree1: fix out of memory error running on esp8266
- extmod/ticks_diff: test for new semantics of ticks_diff()
- extmod/framebuf1: test framebuffer pixel clear, and text function

minimal port:
- Makefile: split rule for firmware.bin generation

unix port:
- Makefile: remove references to deprecated pip-micropython
- modtime: use ticks_diff() implementation from extmod/utime_mphal.c
- mphalport.h: add warning of mp_hal_delay_ms() implementation
- modtime: switch ticks/sleep_ms/us() to utime_mphal
- fix symbol references for x86 Mac
- replace upip tarball with just source file

windows port:
- enable utime_mphal following unix, define mp_hal_ticks_*
- fix utime_mphal compilation for msvc
- implement mp_hal_ticks_cpu in terms of QueryPerformanceCounter

qemu-arm port:
- exclude ticks_diff test for qemu-arm port
- exclude extmod/vfs_fat_fileio.py test
- exclude new vfs_fat tests
- enable software floating point support, and float tests

stmhal port:
- modutime: refactor to use extmod's version of ticks_cpu
- refactor pin usage to use mp_hal_pin API
- led: refactor LED to use mp_hal_pin_output() init function
- Makefile: use standard rules for frozen module generation
- modutime: consistently convert to MP_ROM_QSTR/MP_ROM_PTR
- enable SD power save (disable CLK on idle)

cc3200 port:
- use mp_raise_XXX helper functions to reduce code size
- mods/pybspi: allow "write" arg of read/readinto to be positional
- enable loading of precompiled .mpy files
- fix thread mutex's so threading works with interrupts

teensy port:
- update to provide new mp_hal_pin_XXX functions following stmhal

esp8266 port:
- Makefile: use latest esptool.py flash size auto-detection
- esp_init_data: auto-initialize system params with vendor SDK 2.0.0
- esp8266.ld: move help.o to iROM
- esp8266.ld: move modmachine.o to iROM
- esp8266.ld: move main.o to iROM
- add MP_FASTCODE modifier to put a function to iRAM
- main: mark nlr_jump_fail() as MP_FASTCODE
- modules/webrepl: enforce only one concurrent WebREPL connection
- etshal.h: add few more ESP8266 vendor lib prototypes
- modesp: add flash_user_start() function
- add support for building firmware version for 512K modules
- scripts: make neopixel/apa102 handle 4bpp LEDs with common code
- modutime: consistently convert to MP_ROM_QSTR/MP_ROM_PTR
- modnetwork: config(): fix copy-paste error in setting "mac"
- scripts/port_diag: add descriptions for esf_buf types
- modnetwork.c: allows AP reconnection without WiFi credentials
- main: bump heap size to 36K
- etshal.h: add prototypes for SPIRead/SPIWrite/SPIEraseSector
- etshal.h: adjust size of MD5_CTX structure
- modules: fix negative temperature in ds18x20 driver
- rename "machine" module implementation to use contemporary naming
- rework webrepl_setup to run over wired REPL
- espneopixel.c: solve glitching LED issues with cpu at 80MHz
- include upip as a standard frozen bytecode module
- update docs for esptool 1.2.1/SDK 2.0 (--flash_size=detect)
- modnetwork.c: expose configuration for station DHCP hostname

zephyr port:
- implement utime module
- use board/SoC values for startup banner based on Zephyr config
- initial implementation of machine.Pin
- zephyr_getchar: update for recent Zephyr refactor of console hooks
- support time -> utime module "weaklink"
- README: update for the current featureset, add more info
- mpconfigport.h: move less important params to the bottom
- Makefile: allow to adjust heap size from make command line
- Makefile: update comments to the current state of affairs
- Makefile: allow to override Zephyr config from make command line
- Makefile: add minimal port
- Makefile: add -fomit-frame-pointer to reduce code size
- mphalport.h: update for new "unified" kernal API (sleep functions)

docs:
- machine.SPI: bring up to date with Hardware API, make vendor-neutral
- machine.SPI: improve descriptions of xfer methods
- library/builtins: add docs for delattr and slice
- library/network: reword intro paragraph
- library/network: typo fixes, consistent acronym capitalization
- library/index: update TOCs so builtins sorted before modules
- utime: document ticks_cpu() in more detail
- utime: describe new semantics of ticks_diff() (signed ring arithmetics)
- utime: add docs for ticks_add(), improvements for other ticks_*()
- esp8266: update for new WebREPL setup procedure
- */quickref.rst: use new semantics of ticks_diff()
- library/machine.Pin: update Pin docs to align with new HW API

travis:
- integrate tools/check_code_size.sh
- minimal: Use CROSS=1, for binary size check

examples:
- http_server_simplistic: add "not suitable for real use" note
- hwapi: example showing best practices for HW API usage in apps
- hwapi: add hwconfig for DragonBoard 410c

1 files changed, 192 insertions, 113 deletions

diff --git a/docs/library/machine.Pin.rst b/docs/library/machine.Pin.rst
index db25787f94..952131f099 100644
--- a/docs/library/machine.Pin.rst
+++ b/docs/library/machine.Pin.rst
@@ -3,16 +3,44 @@
 class Pin -- control I/O pins
 =============================
 
-A pin is the basic object to control I/O pins (also known as GPIO -
-general-purpose input/output). It has methods to set
-the mode of the pin (input, output, etc) and methods to get and set the
-digital logic level. For analog control of a pin, see the ADC class.
+A pin object is used to control I/O pins (also known as GPIO - general-purpose
+input/output).  Pin objects are commonly associated with a physical pin that can
+drive an output voltage and read input voltages.  The pin class has methods to set the mode of
+the pin (IN, OUT, etc) and methods to get and set the digital logic level.
+For analog control of a pin, see the :class:`ADC` class.
 
-Usage Model:
+A pin object is constructed by using an identifier which unambiguously
+specifies a certain I/O pin.  The allowed forms of the identifier and the
+physical pin that the identifier maps to are port-specific.  Possibilities
+for the identifier are an integer, a string or a tuple with port and pin
+number.
+
+Usage Model::
+
+    from machine import Pin
+
+    # create an output pin on pin #0
+    p0 = Pin(0, Pin.OUT)
+
+    # set the value low then high
+    p0.value(0)
+    p0.value(1)
+
+    # create an input pin on pin #2, with a pull up resistor
+    p2 = Pin(2, Pin.IN, Pin.PULL_UP)
+
+    # read and print the pin value
+    print(p2.value())
+
+    # reconfigure pin #0 in input mode
+    p0.mode(p0.IN)
+
+    # configure an irq callback
+    p0.irq(lambda p:print(p))
 
 .. only:: port_wipy
 
-    Board pins are identified by their string id::
+    On the WiPy board the pins are identified by their string id::
 
         from machine import Pin
         g = machine.Pin('GP9', mode=Pin.OUT, pull=None, drive=Pin.MED_POWER, alt=-1)
@@ -40,174 +68,224 @@ Usage Model:
     All pin objects go through the pin mapper to come up with one of the
     gpio pins.
 
-.. only:: port_esp8266
+    For the ``drive`` parameter the strengths are:
 
-   ::
+      - ``Pin.LOW_POWER`` - 2mA drive capability.
+      - ``Pin.MED_POWER`` - 4mA drive capability.
+      - ``Pin.HIGH_POWER`` - 6mA drive capability.
 
-    from machine import Pin
+    For the ``alt`` parameter please refer to the pinout and alternate functions
+    table at <https://raw.githubusercontent.com/wipy/wipy/master/docs/PinOUT.png>`_
+    for the specific alternate functions that each pin supports.
 
-    # create an output pin on GPIO0
-    p0 = Pin(0, Pin.OUT)
-    p0.value(0)
-    p0.value(1)
+    For interrupts, the ``priority`` can take values in the range 1-7.  And the
+    ``wake`` parameter has the following properties:
 
-    # create an input pin on GPIO2
-    p2 = Pin(2, Pin.IN, Pin.PULL_UP)
-    print(p2.value())
+      - If ``wake_from=machine.Sleep.ACTIVE`` any pin can wake the board.
+      - If ``wake_from=machine.Sleep.SUSPENDED`` pins ``GP2``, ``GP4``, ``GP10``,
+        ``GP11``, GP17`` or ``GP24`` can wake the board. Note that only 1
+        of this pins can be enabled as a wake source at the same time, so, only
+        the last enabled pin as a ``machine.Sleep.SUSPENDED`` wake source will have effect.
+      - If ``wake_from=machine.Sleep.SUSPENDED`` pins ``GP2``, ``GP4``, ``GP10``,
+        ``GP11``, ``GP17`` and ``GP24`` can wake the board. In this case all of the
+        6 pins can be enabled as a ``machine.Sleep.HIBERNATE`` wake source at the same time.
 
 Constructors
 ------------
 
-.. class:: Pin(id, ...)
+.. class:: Pin(id, mode=-1, pull=-1, \*, value, drive, alt)
 
-   Create a new Pin object associated with the id.  If additional arguments are given,
-   they are used to initialise the pin.  See :meth:`Pin.init`.
+   Access the pin peripheral (GPIO pin) associated with the given ``id``.  If
+   additional arguments are given in the constructor then they are used to initialise
+   the pin.  Any settings that are not specified will remain in their previous state.
 
-Methods
--------
+   The arguments are:
 
-.. only:: port_wipy
+     - ``id`` is mandatory and can be an arbitrary object.  Among possible value
+       types are: int (an internal Pin identifier), str (a Pin name), and tuple
+       (pair of [port, pin]).
 
-    .. method:: Pin.init(mode, pull, \*, drive, alt)
-    
-       Initialise the pin:
+     - ``mode`` specifies the pin mode, which can be one of:
 
-         - ``mode`` can be one of:
+       - ``Pin.IN`` - Pin is configured for input.  If viewed as an output the pin
+         is in high-impedance state.
 
-            - ``Pin.IN``  - input pin.
-            - ``Pin.OUT`` - output pin in push-pull mode.
-            - ``Pin.OPEN_DRAIN`` - output pin in open-drain mode.
-            - ``Pin.ALT`` - pin mapped to an alternate function.
-            - ``Pin.ALT_OPEN_DRAIN`` - pin mapped to an alternate function in open-drain mode.
+       - ``Pin.OUT`` - Pin is configured for (normal) output.
 
-         - ``pull`` can be one of:
+       - ``Pin.OPEN_DRAIN`` - Pin is configured for open-drain output. Open-drain
+         output works in the following way: if the output value is set to 0 the pin
+         is active at a low level; if the output value is 1 the pin is in a high-impedance
+         state.  Not all ports implement this mode, or some might only on certain pins.
 
-            - ``None`` - no pull up or down resistor.
-            - ``Pin.PULL_UP`` - pull up resistor enabled.
-            - ``Pin.PULL_DOWN`` - pull down resistor enabled.
+       - ``Pin.ALT`` - Pin is configured to perform an alternative function, which is
+         port specific.  For a pin configured in such a way any other Pin methods
+         (except :meth:`Pin.init`) are not applicable (calling them will lead to undefined,
+         or a hardware-specific, result).  Not all ports implement this mode.
 
-         - ``drive`` can be one of:
+       - ``Pin.ALT_OPEN_DRAIN`` - The Same as ``Pin.ALT``, but the pin is configured as
+         open-drain.  Not all ports implement this mode.
 
-            - ``Pin.LOW_POWER`` - 2mA drive capability.
-            - ``Pin.MED_POWER`` - 4mA drive capability.
-            - ``Pin.HIGH_POWER`` - 6mA drive capability.
+     - ``pull`` specifies if the pin has a (weak) pull resistor attached, and can be
+       one of:
 
-         - ``alt`` is the number of the alternate function. Please refer to the
-           `pinout and alternate functions table. <https://raw.githubusercontent.com/wipy/wipy/master/docs/PinOUT.png>`_
-           for the specific alternate functions that each pin supports.
+       - ``None`` - No pull up or down resistor.
+       - ``Pin.PULL_UP`` - Pull up resistor enabled.
+       - ``Pin.PULL_DOWN`` - Pull down resistor enabled.
 
-       Returns: ``None``.
+     - ``value`` is valid only for Pin.OUT and Pin.OPEN_DRAIN modes and specifies initial
+       output pin value if given, otherwise the state of the pin peripheral remains
+       unchanged.
 
-    .. method:: Pin.id()
+     - ``drive`` specifies the output power of the pin and can be one of: ``Pin.LOW_POWER``,
+       ``Pin.MED_POWER`` or ``Pin.HIGH_POWER``.  The actual current driving capabilities
+       are port dependent.  Not all ports implement this argument.
 
-       Get the pin id.
+     - ``alt`` specifies an alternate function for the pin and the values it can take are
+       port dependent.  This argument is valid only for ``Pin.ALT`` and ``Pin.ALT_OPEN_DRAIN``
+       modes.  It may be used when a pin supports more than one alternate function.  If only
+       one pin alternate function is supported the this argument is not required.  Not all
+       ports implement this argument.
 
-.. only:: port_esp8266
+   As specified above, the Pin class allows to set an alternate function for a particular
+   pin, but it does not specify any further operations on such a pin.  Pins configured in
+   alternate-function mode are usually not used as GPIO but are instead driven by other
+   hardware peripherals.  The only operation supported on such a pin is re-initialising,
+   by calling the constructor or :meth:`Pin.init` method.  If a pin that is configured in
+   alternate-function mode is re-initialised with ``Pin.IN``, ``Pin.OUT``, or
+   ``Pin.OPEN_DRAIN``, the alternate function will be removed from the pin.
 
-    .. method:: Pin.init(mode, pull=None, \*, value)
+Methods
+-------
 
-       Initialise the pin:
+.. method:: Pin.init(mode=-1, pull=-1, \*, value, drive, alt)
 
-         - `mode` can be one of:
+   Re-initialise the pin using the given parameters.  Only those arguments that
+   are specified will be set.  The rest of the pin peripheral state will remain
+   unchanged.  See the constructor documentation for details of the arguments.
 
-            - ``Pin.IN``  - input pin.
-            - ``Pin.OUT`` - output pin in push-pull mode.
+   Returns ``None``.
 
-         - `pull` can be one of:
+.. method:: Pin.value([x])
 
-            - ``None`` - no pull up or down resistor.
-            - ``Pin.PULL_UP`` - pull up resistor enabled.
+   This method allows to set and get the value of the pin, depending on whether
+   the argument ``x`` is supplied or not.
 
-         - if `value` is given then it is the output value to set the pin
-           if it is in output mode.
+   If the argument is omitted then this method gets the digital logic level of
+   the pin, returning 0 or 1 corresponding to low and high voltage signals
+   respectively.  The behaviour of this method depends on the mode of the pin:
 
-.. method:: Pin.value([value])
+     - ``Pin.IN`` - The method returns the actual input value currently present
+       on the pin.
+     - ``Pin.OUT`` - The behaviour and return value of the method is undefined.
+     - ``Pin.OPEN_DRAIN`` - If the pin is in state '0' then the behaviour and
+       return value of the method is undefined.  Otherwise, if the pin is in
+       state '1', the method returns the actual input value currently present
+       on the pin.
 
-   Get or set the digital logic level of the pin:
+   If the argument is supplied then this method sets the digital logic level of
+   the pin.  The argument ``x`` can be anything that converts to a boolean.
+   If it converts to ``True``, the pin is set to state '1', otherwise it is set
+   to state '0'.  The behaviour of this method depends on the mode of the pin:
 
-     - With no argument, return 0 or 1 depending on the logic level of the pin.
-     - With ``value`` given, set the logic level of the pin.  ``value`` can be
-       anything that converts to a boolean.  If it converts to ``True``, the pin
-       is set high, otherwise it is set low.
+     - ``Pin.IN`` - The value is stored in the output buffer for the pin.  The
+       pin state does not change, it remains in the high-impedance state.  The
+       stored value will become active on the pin as soon as it is changed to
+       ``Pin.OUT`` or ``Pin.OPEN_DRAIN`` mode.
+     - ``Pin.OUT`` - The output buffer is set to the given value immediately.
+     - ``Pin.OPEN_DRAIN`` - If the value is '0' the pin is set to a low voltage
+       state.  Otherwise the pin is set to high-impedance state.
 
-.. method:: Pin.__call__([value])
+   When setting the value this method returns ``None``.
 
-   Pin objects are callable. The call method provides a (fast) shortcut to set and get the value of the pin.
-   See :func:`Pin.value` for more details.
+.. method:: Pin.out_value()
 
-.. method:: Pin.alt_list()
+   Return the value stored in the output buffer of a pin, regardless of its mode.
 
-    Returns a list of the alternate functions supported by the pin. List items are
-    a tuple of the form: ``('ALT_FUN_NAME', ALT_FUN_INDEX)``
+   Not all ports implement this method.
 
-    Availability: WiPy.
+.. method:: Pin.__call__([x])
 
-.. only:: port_wipy
+   Pin objects are callable.  The call method provides a (fast) shortcut to set
+   and get the value of the pin.  It is equivalent to Pin.value([x]).
+   See :meth:`Pin.value` for more details.
+
+.. method:: Pin.toggle()
+
+   Toggle the output value of the pin.  Equivalent to ``pin.value(not pin.out_value())``.
+   Returns ``None``.
+
+   Not all ports implement this method.
 
-    .. method:: Pin.toggle()
+   Availability: WiPy.
 
-        Toggle the value of the pin.
+.. method:: Pin.id()
 
-    .. method:: Pin.mode([mode])
+   Get the pin identifier.  This may return the ``id`` as specified in the
+   constructor.  Or it may return a canonical software-specific pin id.
 
-        Get or set the pin mode.
+.. method:: Pin.mode([mode])
 
-    .. method:: Pin.pull([pull])
+   Get or set the pin mode.
+   See the constructor documentation for details of the ``mode`` argument.
 
-        Get or set the pin pull.
+.. method:: Pin.pull([pull])
 
-    .. method:: Pin.drive([drive])
+   Get or set the pin pull state.
+   See the constructor documentation for details of the ``pull`` argument.
 
-        Get or set the pin drive strength.
+.. method:: Pin.drive([drive])
 
-    .. method:: Pin.irq(\*, trigger, priority=1, handler=None, wake=None)
+   Get or set the pin drive strength.
+   See the constructor documentation for details of the ``drive`` argument.
 
-        Create a callback to be triggered when the input level at the pin changes.
+   Not all ports implement this method.
 
-            - ``trigger`` configures the pin level which can generate an interrupt. Possible values are:
+   Availability: WiPy.
 
-                - ``Pin.IRQ_FALLING`` interrupt on falling edge.
-                - ``Pin.IRQ_RISING`` interrupt on rising edge.
-                - ``Pin.IRQ_LOW_LEVEL`` interrupt on low level.
-                - ``Pin.IRQ_HIGH_LEVEL`` interrupt on high level.
-              
-              The values can be *ORed* together, for instance mode=Pin.IRQ_FALLING | Pin.IRQ_RISING
+.. method:: Pin.irq(handler=None, trigger=(Pin.IRQ_FALLING | Pin.IRQ_RISING), \*, priority=1, wake=None)
 
-            - ``priority`` level of the interrupt. Can take values in the range 1-7.
-              Higher values represent higher priorities.
-            - ``handler`` is an optional function to be called when new characters arrive.
-            - ``wakes`` selects the power mode in which this interrupt can wake up the
-              board. Please note:
+   Configure an interrupt handler to be called when the trigger source of the
+   pin is active.  If the pin mode is ``Pin.IN`` then the trigger source is
+   the external value on the pin.  If the pin mode is ``Pin.OUT`` then the
+   trigger source is the output buffer of the pin.  Otherwise, if the pin mode
+   is ``Pin.OPEN_DRAIN`` then the trigger source is the output buffer for
+   state '0' and the external pin value for state '1'.
 
-              - If ``wake_from=machine.Sleep.ACTIVE`` any pin can wake the board.
-              - If ``wake_from=machine.Sleep.SUSPENDED`` pins ``GP2``, ``GP4``, ``GP10``,
-                ``GP11``, GP17`` or ``GP24`` can wake the board. Note that only 1
-                of this pins can be enabled as a wake source at the same time, so, only
-                the last enabled pin as a ``machine.Sleep.SUSPENDED`` wake source will have effect.
-              - If ``wake_from=machine.Sleep.SUSPENDED`` pins ``GP2``, ``GP4``, ``GP10``,
-                ``GP11``, ``GP17`` and ``GP24`` can wake the board. In this case all of the
-                6 pins can be enabled as a ``machine.Sleep.HIBERNATE`` wake source at the same time.
-              - Values can be ORed to make a pin generate interrupts in more than one power
-                mode.
+   The arguments are:
 
-            Returns a callback object.
+     - ``handler`` is an optional function to be called when the interrupt
+       triggers.
 
-.. only:: port_esp8266
+     - ``trigger`` configures the event which can generate an interrupt.
+       Possible values are:
 
-    .. method:: Pin.irq(\*, trigger, handler=None)
+       - ``Pin.IRQ_FALLING`` interrupt on falling edge.
+       - ``Pin.IRQ_RISING`` interrupt on rising edge.
+       - ``Pin.IRQ_LOW_LEVEL`` interrupt on low level.
+       - ``Pin.IRQ_HIGH_LEVEL`` interrupt on high level.
 
-        Create a callback to be triggered when the input level at the pin changes.
+       These values can be OR'ed together to trigger on multiple events.
 
-            - ``trigger`` configures the pin level which can generate an interrupt. Possible values are:
+     - ``priority`` sets the priority level of the interrupt.  The values it
+       can take are port-specific, but higher values always represent higher
+       priorities.
+
+     - ``wake`` selects the power mode in which this interrupt can wake up the
+       system.  It can be ``machine.IDLE``, ``machine.SLEEP`` or ``machine.DEEPSLEEP``.
+       These values can also be OR'ed together to make a pin generate interrupts in
+       more than one power mode.
+
+   This method returns a callback object.
+
+.. only:: port_wipy
 
-                - ``Pin.IRQ_FALLING`` interrupt on falling edge.
-                - ``Pin.IRQ_RISING`` interrupt on rising edge.
+    .. method:: Pin.alt_list()
 
-              The values can be OR'ed together to trigger on multiple events.
+       Returns a list of the alternate functions supported by the pin. List items are
+       a tuple of the form: ``('ALT_FUN_NAME', ALT_FUN_INDEX)``
 
-            - ``handler`` is an optional function to be called when the interrupt triggers.
+       Availability: WiPy.
 
-            Returns a callback object.
 
 Attributes
 ----------
@@ -239,7 +317,8 @@ not all constants are available on all ports.
 .. data:: Pin.PULL_UP
           Pin.PULL_DOWN
 
-   Selects the whether there is a pull up/down resistor.
+   Selects whether there is a pull up/down resistor.  Use the value
+   ``None`` for no pull.
 
 .. data:: Pin.LOW_POWER
           Pin.MED_POWER