339314535b
Commit 8dfbf64c36 ("Fix spidev path mismatch (#216)")
changes how the SPI constructor maps to the spidev entry.
Update the documentation to reflect this change.
Signed-off-by: Franklin S Cooper Jr <fcooper27@gmail.com>
134 lines
3.3 KiB
ReStructuredText
134 lines
3.3 KiB
ReStructuredText
:mod:`SPI` --- Serial Peripheral Interface
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------------------------------------------
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This module defines an object type that allows Serial Peripheral Interface
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(SPI) bus transactions on hosts running the Linux kernel. The host kernel
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must have SPI support and SPI device interface support.
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Because the SPI device interface is opened R/W, users of this module
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usually must have root permissions or be members of a group with granted
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access rights.
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Pins used for SPI0 and SPI1
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+++++++++++++++++++++++++++
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==== ===== ===== ===== =====
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PORT CS0 DO DI SCLK
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==== ===== ===== ===== =====
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SPI0 P9_17 P9_21 P9_18 P9_22
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SPI1 P9_28 P9_29 P9_30 P9_31
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==== ===== ===== ===== =====
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Example::
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import Adafruit_BBIO.SPI as SPI
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from Adafruit_BBIO.SPI import SPI
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# spi = SPI(bus, device) #/dev/spidev<bus>.<device>
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# /dev/spidev0.0
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spi = SPI(0, 0)
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print(spi.xfer2([32, 11, 110, 22, 220]))
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spi.close()
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# /dev/spidev0.1
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spi = SPI(0, 1)
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print(spi.xfer2([32, 11, 110, 22, 220]))
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spi.close()
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# /dev/spidev1.0
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spi = SPI(1, 0)
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print(spi.xfer2([32, 11, 110, 22, 220]))
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spi.close()
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# /dev/spidev1.1
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spi = SPI(1, 1)
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print(spi.xfer2([32, 11, 110, 22, 220]))
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spi.close()
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.. module:: Adafruit_BBIO.SPI
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.. class:: SPI(bus, client)
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:param bus: bus number.
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:param client: client device number.
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:returns: a new SPI object, optionally connected to the specified SPI
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device interface.
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:rtype: :class:`SPI`
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.. attribute:: bpw
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Bits per word.
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.. attribute:: cshigh
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Chip Select (CS or Slave Select, SS) active high.
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.. attribute:: loop
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Loopback configuration.
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.. attribute:: lsbfirst
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Least Significant Bit (LSB) first.
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.. attribute:: mode
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SPI mode as two bit pattern of Clock Polarity and Phase [CPOL|CPHA]; min-- 0b00 = 0, max-- 0b11 = 3.
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.. attribute:: msh
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Maximum speed in Hz.
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.. attribute:: threewire
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SI/SO signals are shared.
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.. method:: open(bus, device)
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Connects the object to the specified SPI device. `open(X, Y)` will open
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`/dev/spidev-X.Y`
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:param int bus: bus number
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:param str device: device number
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.. method:: close()
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Disconnects the object from the interface.
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.. method:: readbytes(len)
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Read the specified length of bytes from the SPI device.
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:param int len: length of bytes to read, 1024 maximum.
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:returns: values read
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:rtype: list[int]
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.. method:: writebytes(values)
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Write bytes to the SPI device.
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:param values: list of values to write, with a maximum length of 1024.
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:type values: list[int]
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.. method:: xfer(values[,delay=0])
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Perform an SPI transaction of values. Slave Select (SS or CS) will be
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released and reactivated between blocks.
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:param values: list of values to transfer, with a maximum length of 1024.
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:type values: list[int]
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:param delay: delay in microseconds between blocks.
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:returns: values transferred
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:rtype: list[int]
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.. method:: xfer2(values)
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Perform an SPI transaction of values. Slave Select (SS or CS) will be
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held active between blocks.
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:param values: list of values to transfer, with a maximum length of 1024.
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:type values: list[int]
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:returns: values transferred
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:rtype: list[int]
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