.. currentmodule:: esp32
:mod:`esp32` --- functionality specific to the ESP32
====================================================
.. module:: esp32
:synopsis: functionality specific to the ESP32
The ``esp32`` module contains functions and classes specifically aimed at
controlling ESP32 modules.
Functions
---------
.. function:: wake_on_touch(wake)
Configure whether or not a touch will wake the device from sleep.
*wake* should be a boolean value.
.. function:: wake_on_ext0(pin, level)
Configure how EXT0 wakes the device from sleep. *pin* can be ``None``
or a valid Pin object. *level* should be ``esp32.WAKEUP_ALL_LOW`` or
``esp32.WAKEUP_ANY_HIGH``.
.. function:: wake_on_ext1(pins, level)
Configure how EXT1 wakes the device from sleep. *pins* can be ``None``
or a tuple/list of valid Pin objects. *level* should be ``esp32.WAKEUP_ALL_LOW``
or ``esp32.WAKEUP_ANY_HIGH``.
.. function:: raw_temperature()
Read the raw value of the internal temperature sensor, returning an integer.
.. function:: hall_sensor()
Read the raw value of the internal Hall sensor, returning an integer.
.. function:: idf_heap_info(capabilities)
Returns information about the ESP-IDF heap memory regions. One of them contains
the MicroPython heap and the others are used by ESP-IDF, e.g., for network
buffers and other data. This data is useful to get a sense of how much memory
is available to ESP-IDF and the networking stack in particular. It may shed
some light on situations where ESP-IDF operations fail due to allocation failures.
The information returned is *not* useful to troubleshoot Python allocation failures,
use `micropython.mem_info()` instead.
The capabilities parameter corresponds to ESP-IDF's ``MALLOC_CAP_XXX`` values but the
two most useful ones are predefined as `esp32.HEAP_DATA` for data heap regions and
`esp32.HEAP_EXEC` for executable regions as used by the native code emitter.
The return value is a list of 4-tuples, where each 4-tuple corresponds to one heap
and contains: the total bytes, the free bytes, the largest free block, and
the minimum free seen over time.
Example after booting::
>>> import esp32; esp32.idf_heap_info(esp32.HEAP_DATA)
[(240, 0, 0, 0), (7288, 0, 0, 0), (16648, 4, 4, 4), (79912, 35712, 35512, 35108),
(15072, 15036, 15036, 15036), (113840, 0, 0, 0)]
Flash partitions
----------------
This class gives access to the partitions in the device's flash memory and includes
methods to enable over-the-air (OTA) updates.
.. class:: Partition(id)
Create an object representing a partition. *id* can be a string which is the label
of the partition to retrieve, or one of the constants: ``BOOT`` or ``RUNNING``.
.. classmethod:: Partition.find(type=TYPE_APP, subtype=0xff, label=None)
Find a partition specified by *type*, *subtype* and *label*. Returns a
(possibly empty) list of Partition objects. Note: ``subtype=0xff`` matches any subtype
and ``label=None`` matches any label.
.. method:: Partition.info()
Returns a 6-tuple ``(type, subtype, addr, size, label, encrypted)``.
.. method:: Partition.readblocks(block_num, buf)
Partition.readblocks(block_num, buf, offset)
.. method:: Partition.writeblocks(block_num, buf)
Partition.writeblocks(block_num, buf, offset)
.. method:: Partition.ioctl(cmd, arg)
These methods implement the simple and :ref:`extended
<block-device-interface>` block protocol defined by
:class:`uos.AbstractBlockDev`.
.. method:: Partition.set_boot()
Sets the partition as the boot partition.
.. method:: Partition.get_next_update()
Gets the next update partition after this one, and returns a new Partition object.
Typical usage is ``Partition(Partition.RUNNING).get_next_update()``
which returns the next partition to update given the current running one.
.. classmethod:: Partition.mark_app_valid_cancel_rollback()
Signals that the current boot is considered successful.
Calling ``mark_app_valid_cancel_rollback`` is required on the first boot of a new
partition to avoid an automatic rollback at the next boot.
This uses the ESP-IDF "app rollback" feature with "CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE"
and an ``OSError(-261)`` is raised if called on firmware that doesn't have the
feature enabled.
It is OK to call ``mark_app_valid_cancel_rollback`` on every boot and it is not
necessary when booting firmare that was loaded using esptool.
Constants
~~~~~~~~~
.. data:: Partition.BOOT
Partition.RUNNING
Used in the `Partition` constructor to fetch various partitions: ``BOOT`` is the
partition that will be booted at the next reset and ``RUNNING`` is the currently
running partition.
.. data:: Partition.TYPE_APP
Partition.TYPE_DATA
Used in `Partition.find` to specify the partition type: ``APP`` is for bootable
firmware partitions (typically labelled ``factory``, ``ota_0``, ``ota_1``), and
``DATA`` is for other partitions, e.g. ``nvs``, ``otadata``, ``phy_init``, ``vfs``.
.. data:: HEAP_DATA
HEAP_EXEC
Used in `idf_heap_info`.
.. _esp32.RMT:
RMT
---
The RMT (Remote Control) module, specific to the ESP32, was originally designed
to send and receive infrared remote control signals. However, due to a flexible
design and very accurate (as low as 12.5ns) pulse generation, it can also be
used to transmit or receive many other types of digital signals::
import esp32
from machine import Pin
r = esp32.RMT(0, pin=Pin(18), clock_div=8)
r # RMT(channel=0, pin=18, source_freq=80000000, clock_div=8)
# To use carrier frequency
r = esp32.RMT(0, pin=Pin(18), clock_div=8, carrier_freq=38000)
r # RMT(channel=0, pin=18, source_freq=80000000, clock_div=8, carrier_freq=38000, carrier_duty_percent=50)
# The channel resolution is 100ns (1/(source_freq/clock_div)).
r.write_pulses((1, 20, 2, 40), start=0) # Send 0 for 100ns, 1 for 2000ns, 0 for 200ns, 1 for 4000ns
The input to the RMT module is an 80MHz clock (in the future it may be able to
configure the input clock but, for now, it's fixed). ``clock_div`` *divides*
the clock input which determines the resolution of the RMT channel. The
numbers specificed in ``write_pulses`` are multiplied by the resolution to
define the pulses.
``clock_div`` is an 8-bit divider (0-255) and each pulse can be defined by
multiplying the resolution by a 15-bit (0-32,768) number. There are eight
channels (0-7) and each can have a different clock divider.
To enable the carrier frequency feature of the esp32 hardware, specify the
``carrier_freq`` as something like 38000, a typical IR carrier frequency.
So, in the example above, the 80MHz clock is divided by 8. Thus the
resolution is (1/(80Mhz/8)) 100ns. Since the ``start`` level is 0 and toggles
with each number, the bitstream is ``0101`` with durations of [100ns, 2000ns,
100ns, 4000ns].
For more details see Espressif's `ESP-IDF RMT documentation.
<https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/rmt.html>`_.
.. Warning::
The current MicroPython RMT implementation lacks some features, most notably
receiving pulses. RMT should be considered a
*beta feature* and the interface may change in the future.
.. class:: RMT(channel, *, pin=None, clock_div=8, carrier_freq=0, carrier_duty_percent=50)
This class provides access to one of the eight RMT channels. *channel* is
required and identifies which RMT channel (0-7) will be configured. *pin*,
also required, configures which Pin is bound to the RMT channel. *clock_div*
is an 8-bit clock divider that divides the source clock (80MHz) to the RMT
channel allowing the resolution to be specified. *carrier_freq* is used to
enable the carrier feature and specify its frequency, default value is ``0``
(not enabled). To enable, specify a positive integer. *carrier_duty_percent*
defaults to 50.
.. method:: RMT.source_freq()
Returns the source clock frequency. Currently the source clock is not
configurable so this will always return 80MHz.
.. method:: RMT.clock_div()
Return the clock divider. Note that the channel resolution is
``1 / (source_freq / clock_div)``.
.. method:: RMT.wait_done(timeout=0)
Returns ``True`` if the channel is currently transmitting a stream of pulses
started with a call to `RMT.write_pulses`.
If *timeout* (defined in ticks of ``source_freq / clock_div``) is specified
the method will wait for *timeout* or until transmission is complete,
returning ``False`` if the channel continues to transmit. If looping is
enabled with `RMT.loop` and a stream has started, then this method will
always (wait and) return ``False``.
.. method:: RMT.loop(enable_loop)
Configure looping on the channel. *enable_loop* is bool, set to ``True`` to
enable looping on the *next* call to `RMT.write_pulses`. If called with
``False`` while a looping stream is currently being transmitted then the
current set of pulses will be completed before transmission stops.
.. method:: RMT.write_pulses(pulses, start)
Begin sending *pulses*, a list or tuple defining the stream of pulses. The
length of each pulse is defined by a number to be multiplied by the channel
resolution ``(1 / (source_freq / clock_div))``. *start* defines whether the
stream starts at 0 or 1.
If transmission of a stream is currently in progress then this method will
block until transmission of that stream has ended before beginning sending
*pulses*.
If looping is enabled with `RMT.loop`, the stream of pulses will be repeated
indefinitely. Further calls to `RMT.write_pulses` will end the previous
stream - blocking until the last set of pulses has been transmitted -
before starting the next stream.
Ultra-Low-Power co-processor
----------------------------
.. class:: ULP()
This class provides access to the Ultra-Low-Power co-processor.
.. method:: ULP.set_wakeup_period(period_index, period_us)
Set the wake-up period.
.. method:: ULP.load_binary(load_addr, program_binary)
Load a *program_binary* into the ULP at the given *load_addr*.
.. method:: ULP.run(entry_point)
Start the ULP running at the given *entry_point*.
Constants
---------
.. data:: esp32.WAKEUP_ALL_LOW
esp32.WAKEUP_ANY_HIGH
Selects the wake level for pins.