Diff: SWSPI.cpp

Revision:

0:6a500a08c7fd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SWSPI.cpp	Tue Feb 04 06:54:01 2014 +0000
@@ -0,0 +1,86 @@
+/* SWSPI, Software SPI library
+ * Copyright (c) 2012-2014, David R. Van Wagner, http://techwithdave.blogspot.com
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <mbed.h>
+#include "SWSPI.h"
+
+SWSPI::SWSPI(PinName mosi_pin, PinName miso_pin, PinName sclk_pin)
+{
+    mosi = new DigitalOut(mosi_pin);
+    miso = new DigitalIn(miso_pin);
+    sclk = new DigitalOut(sclk_pin);
+    format(8);
+    frequency();
+}
+
+SWSPI::~SWSPI()
+{
+    delete mosi;
+    delete miso;
+    delete sclk;
+}
+
+void SWSPI::format(int bits, int mode)
+{
+    this->bits = bits;
+    this->mode = mode;
+    polarity = (mode >> 1) & 1;
+    phase = mode & 1;
+    sclk->write(polarity);
+}
+
+void SWSPI::frequency(int hz)
+{
+    this->freq = hz;
+}
+
+int SWSPI::write(int value)
+{
+    int read = 0;
+    for (int bit = bits-1; bit >= 0; --bit)
+    {
+        mosi->write(((value >> bit) & 0x01) != 0);
+
+        if (phase == 0)
+        {
+            if (miso->read())
+                read |= (1 << bit);
+        }
+
+        sclk->write(!polarity);
+
+        wait(1.0/freq/2);
+
+        if (phase == 1)
+        {
+            if (miso->read())
+                read |= (1 << bit);
+        }
+
+        sclk->write(polarity);
+
+        wait(1.0/freq/2);
+    }
+    
+    return read;
+}
+