kopia lustrzana https://github.com/micropython/micropython
134 wiersze
4.0 KiB
ReStructuredText
134 wiersze
4.0 KiB
ReStructuredText
.. currentmodule:: pyb
|
|
.. _pyb.USB_VCP:
|
|
|
|
class USB_VCP -- USB virtual comm port
|
|
======================================
|
|
|
|
The USB_VCP class allows creation of a `stream`-like object representing the USB
|
|
virtual comm port. It can be used to read and write data over USB to
|
|
the connected host.
|
|
|
|
|
|
Constructors
|
|
------------
|
|
|
|
.. class:: USB_VCP(id=0)
|
|
|
|
Create a new USB_VCP object. The *id* argument specifies which USB VCP port to
|
|
use.
|
|
|
|
|
|
Methods
|
|
-------
|
|
|
|
.. method:: USB_VCP.init(*, flow=-1)
|
|
|
|
Configure the USB VCP port. If the *flow* argument is not -1 then the value sets
|
|
the flow control, which can be a bitwise-or of ``USB_VCP.RTS`` and ``USB_VCP.CTS``.
|
|
RTS is used to control read behaviour and CTS, to control write behaviour.
|
|
|
|
.. method:: USB_VCP.setinterrupt(chr)
|
|
|
|
Set the character which interrupts running Python code. This is set
|
|
to 3 (CTRL-C) by default, and when a CTRL-C character is received over
|
|
the USB VCP port, a KeyboardInterrupt exception is raised.
|
|
|
|
Set to -1 to disable this interrupt feature. This is useful when you
|
|
want to send raw bytes over the USB VCP port.
|
|
|
|
.. method:: USB_VCP.isconnected()
|
|
|
|
Return ``True`` if USB is connected as a serial device, else ``False``.
|
|
|
|
.. method:: USB_VCP.any()
|
|
|
|
Return ``True`` if any characters waiting, else ``False``.
|
|
|
|
.. method:: USB_VCP.close()
|
|
|
|
This method does nothing. It exists so the USB_VCP object can act as
|
|
a file.
|
|
|
|
.. method:: USB_VCP.read([nbytes])
|
|
|
|
Read at most ``nbytes`` from the serial device and return them as a
|
|
bytes object. If ``nbytes`` is not specified then the method reads
|
|
all available bytes from the serial device.
|
|
USB_VCP `stream` implicitly works in non-blocking mode,
|
|
so if no pending data available, this method will return immediately
|
|
with ``None`` value.
|
|
|
|
.. method:: USB_VCP.readinto(buf, [maxlen])
|
|
|
|
Read bytes from the serial device and store them into ``buf``, which
|
|
should be a buffer-like object. At most ``len(buf)`` bytes are read.
|
|
If ``maxlen`` is given and then at most ``min(maxlen, len(buf))`` bytes
|
|
are read.
|
|
|
|
Returns the number of bytes read and stored into ``buf`` or ``None``
|
|
if no pending data available.
|
|
|
|
.. method:: USB_VCP.readline()
|
|
|
|
Read a whole line from the serial device.
|
|
|
|
Returns a bytes object containing the data, including the trailing
|
|
newline character or ``None`` if no pending data available.
|
|
|
|
.. method:: USB_VCP.readlines()
|
|
|
|
Read as much data as possible from the serial device, breaking it into
|
|
lines.
|
|
|
|
Returns a list of bytes objects, each object being one of the lines.
|
|
Each line will include the newline character.
|
|
|
|
.. method:: USB_VCP.write(buf)
|
|
|
|
Write the bytes from ``buf`` to the serial device.
|
|
|
|
Returns the number of bytes written.
|
|
|
|
.. method:: USB_VCP.recv(data, *, timeout=5000)
|
|
|
|
Receive data on the bus:
|
|
|
|
- ``data`` can be an integer, which is the number of bytes to receive,
|
|
or a mutable buffer, which will be filled with received bytes.
|
|
- ``timeout`` is the timeout in milliseconds to wait for the receive.
|
|
|
|
Return value: if ``data`` is an integer then a new buffer of the bytes received,
|
|
otherwise the number of bytes read into ``data`` is returned.
|
|
|
|
.. method:: USB_VCP.send(data, *, timeout=5000)
|
|
|
|
Send data over the USB VCP:
|
|
|
|
- ``data`` is the data to send (an integer to send, or a buffer object).
|
|
- ``timeout`` is the timeout in milliseconds to wait for the send.
|
|
|
|
Return value: number of bytes sent.
|
|
|
|
.. method:: USB_VCP.irq(handler=None, trigger=IRQ_RX, hard=False)
|
|
|
|
Register *handler* to be called whenever an event specified by *trigger*
|
|
occurs. The *handler* function must take exactly one argument, which will
|
|
be the USB VCP object. Pass in ``None`` to disable the callback.
|
|
|
|
Valid values for *trigger* are:
|
|
|
|
- ``USB_VCP.IRQ_RX``: new data is available for reading from the USB VCP object.
|
|
|
|
|
|
Constants
|
|
---------
|
|
|
|
.. data:: USB_VCP.RTS
|
|
USB_VCP.CTS
|
|
|
|
to select the flow control type.
|
|
|
|
.. data:: USB_VCP.IRQ_RX
|
|
|
|
IRQ trigger values for :meth:`USB_VCP.irq`.
|