Added software spi stuff

lib/Bus/SoftwareSpiBus.php

@@ -0,0 +1,92 @@
+<?php
+
+/*
+ * Copyright (C) 2014, NoccyLabs
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+namespace NoccyLabs\Gpio\Bus;
+
+class SoftwareSpiBus extends Bus
+{
+    protected $buffer = null;
+
+    protected function configure()
+    {
+        $this->addPin("sclk");
+        $this->addPin("mosi");
+        $this->addPin("miso");
+    }
+
+    protected function spiExchangeByte($byte)
+    {
+        $in = 0;
+        if (is_string($byte)) { $byte = ord($byte); }
+        for($bit=0; $bit<8; $bit++) {
+            $this->setValue("sclk", 0);
+            $this->setValue("mosi", (($byte & 1<<$bit)>0));
+            usleep(5000);
+            $this->setValue("sclk", 1);
+            usleep(5000);
+            if ($this->getValue("miso")) {
+                $in |= 1<<$bit;
+            }
+        }
+        return chr($in);
+    }
+    
+    protected function setValue($pin,$value)
+    {
+        echo "{$pin}→{$value}\n";
+    }
+    protected function getValue($pin)
+    {
+        echo "{$pin}←0\n";
+        return 0;
+    }
+    
+    public function write($data)
+    {
+        for($n = 0; $n < strlen($data); $n++) {
+            $this->buffer .= $this->spiExchangeByte($data[$n]);
+        }
+    }
+    
+    public function read($bytes)
+    {
+        $ret = null;
+        if (strlen($this->buffer)>0) {
+            if (strlen($this->buffer)<$bytes) {
+                $ret = $this->buffer; 
+                $bytes -= strlen($this->buffer);
+                $this->buffer = null; 
+            } else {
+                $ret = substr($this->buffer,0,$bytes);
+                $this->buffer = substr($this->buffer,$bytes);
+                return $ret;
+            }
+        }
+        for($n = 0; $n < $bytes; $n++) {
+            $ret.= $this->spiExchangeByte(0x00);
+        }
+        return $ret;
+    }
+    
+    public function getBufferFill()
+    {
+        return strlen($this->buffer);
+    }
+
+}