Revision 0:6a500a08c7fd, committed 2014-02-04

Comitter:

davervw

Date:

Tue Feb 04 06:54:01 2014 +0000

Commit message:

First revision, tested with lpc1768, lpc11u24, lpc1114fn28, and lpc812

Changed in this revision

--- /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;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SWSPI.h	Tue Feb 04 06:54:01 2014 +0000
@@ -0,0 +1,95 @@
+/* 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.
+ */
+
+#ifndef SWSPI_H
+#define SWSPI_H
+
+/** A software implemented SPI that can use any digital pins
+ *
+ * Useful when don't want to share a single SPI hardware among attached devices
+ * or when pinout doesn't match exactly to the target's SPI pins
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "SWSPI.h"
+ * 
+ * SWSPI spi(p5, p6, p7); // mosi, miso, sclk
+ * 
+ * int main() 
+ * {
+ *     DigitalOut cs(p8);
+ *     spi.format(8, 0);
+ *     spi.frequency(10000000);
+ *     cs.write(0);
+ *     spi.write(0x9f);
+ *     int jedecid = (spi.write(0) << 16) | (spi.write(0) << 8) | spi.write(0);
+ *     cs.write(1);
+ * }
+ * @endcode
+ */
+class SWSPI
+{
+private:
+    DigitalOut* mosi;
+    DigitalIn* miso;
+    DigitalOut* sclk;
+    int port;
+    int bits;
+    int mode;
+    int polarity; // idle clock value
+    int phase; // 0=sample on leading (first) clock edge, 1=trailing (second)
+    int freq;
+    
+public:
+    /** Create SWSPI object
+     *
+     *  @param mosi_pin
+     *  @param miso_pin
+     *  @param sclk_pin
+     */
+    SWSPI(PinName mosi_pin, PinName miso_pin, PinName sclk_pin);
+    
+    /** Destructor */
+    ~SWSPI();
+    
+    /** Specify SPI format
+     *
+     *  @param bits  8 or 16 are typical values
+     *  @param mode  0, 1, 2, or 3 phase (bit1) and idle clock (bit0)
+     */
+    void format(int bits, int mode = 0);
+    
+    /** Specify SPI clock frequency
+     *
+     *  @param hz  frequency (optional, defaults to 10000000)
+     */
+    void frequency(int hz = 10000000);
+    
+    /** Write data and read result
+     *
+     *  @param value  data to write (see format for bit size)
+     *  returns value read from device
+     */
+    int write(int value);
+};
+
+#endif // SWSPI_H