NAME
    RPi::SPI - Communicate with devices over the Serial Peripheral Interface
    (SPI) bus on Raspberry Pi

SYNOPSIS
        my $channel = 0;

        my $spi = RPi::SPI->new($channel);

        my $buf = [0x01, 0x02];
        my $len = 2;

        $buf = $spi->rw($buf, $len);

        # write occurs, then a read, and the read buffer overwrites the
        # write TX buffer, so the read data is in the write buffer after the call

        print "$_\n" for @$buf;

DESCRIPTION
    This distribution provides you the ability to communicate with devices
    attached to the channels on the Serial Peripheral Interface (SPI) bus.
    Although it was designed for the Raspberry Pi, that's not a hard
    requirement, and it should work on any Unix-type system that has support
    for SPI.

METHODS
  new
    Instantiates a new RPi::SPI instance, prepares a specific SPI bus
    channel for use, then returns the object.

    Parameters:

        The SPI bus channel to initialize.

        Mandatory: Integer, `0' for `/dev/spidev0.0' or `1' for
        `/dev/spidev0.1'.

            Optional, Integer. The data rate to communicate on the bus
            using. Defaults to `1000000' (1MHz).

            Dies if we can't open the SPI bus.

  rw
            Writes specified data to the bus on the channel specified in
            `new()', then after completion, does a read of the bus and
            re-populates the write buffer with the freshly read data.

            Parameters:

                Mandatory: Array reference where each element is an unsigned
                char (0-255). This array is the write buffer; the data we'll
                be sending to the SPI bus.

                    Mandatory: Integer, the number of array elements in the
                    `$buf' parameter sent in above.

                    Return: The write buffer, after being re-populated with
                    the read data.

                    Dies if we can't open the SPI bus.

AUTHOR
                    Steve Bertrand, `<steveb at cpan.org>'

LICENSE AND COPYRIGHT
                    Copyright 2017 Steve Bertrand.

                    This program is free software; you can redistribute it
                    and/or modify it under the terms of either: the GNU
                    General Public License as published by the Free Software
                    Foundation; or the Artistic License.

                    See http://dev.perl.org/licenses/ for more information.