93 lines
2.4 KiB
PHP
93 lines
2.4 KiB
PHP
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<?php
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/*
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* Copyright (C) 2014, NoccyLabs
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*/
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namespace NoccyLabs\Gpio\Bus;
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class SoftwareSpiBus extends Bus
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{
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protected $buffer = null;
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protected function configure()
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{
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$this->addPin("sclk");
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$this->addPin("mosi");
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$this->addPin("miso");
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}
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protected function spiExchangeByte($byte)
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{
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$in = 0;
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if (is_string($byte)) { $byte = ord($byte); }
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for($bit=0; $bit<8; $bit++) {
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$this->setValue("sclk", 0);
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$this->setValue("mosi", (($byte & 1<<$bit)>0));
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usleep(5000);
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$this->setValue("sclk", 1);
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usleep(5000);
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if ($this->getValue("miso")) {
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$in |= 1<<$bit;
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}
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}
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return chr($in);
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}
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protected function setValue($pin,$value)
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{
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echo "{$pin}→{$value}\n";
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}
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protected function getValue($pin)
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{
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echo "{$pin}←0\n";
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return 0;
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}
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public function write($data)
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{
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for($n = 0; $n < strlen($data); $n++) {
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$this->buffer .= $this->spiExchangeByte($data[$n]);
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}
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}
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public function read($bytes)
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{
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$ret = null;
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if (strlen($this->buffer)>0) {
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if (strlen($this->buffer)<$bytes) {
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$ret = $this->buffer;
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$bytes -= strlen($this->buffer);
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$this->buffer = null;
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} else {
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$ret = substr($this->buffer,0,$bytes);
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$this->buffer = substr($this->buffer,$bytes);
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return $ret;
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}
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}
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for($n = 0; $n < $bytes; $n++) {
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$ret.= $this->spiExchangeByte(0x00);
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}
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return $ret;
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}
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public function getBufferFill()
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{
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return strlen($this->buffer);
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}
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}
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