Diff: MCP4922.h

Revision:

0:e994c6963c66

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP4922.h	Thu May 15 17:33:40 2014 +0000
@@ -0,0 +1,168 @@
+/* MCP4922 Driver Library
+ * Copyright (c) 2014 Neil Thiessen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MCP4922_H
+#define MCP4922_H
+
+#include "mbed.h"
+
+/** MCP4922 class.
+ *  Used for controlling an MCP4922 DAC connected via SPI.
+ *
+ * Example:
+ * @code
+ * #include "mbed.h"
+ * #include "MCP4922.h"
+ *
+ * //Create an MCP4922 object
+ * MCP4922 dac(p11, p13, p14);
+ *
+ * int main()
+ * {
+ *     //Configure DAC A
+ *     dac.referenceMode(MCP4922::DAC_A, MCP4922::REF_UNBUFFERED);
+ *     dac.gainMode(MCP4922::DAC_A, MCP4922::GAIN_1X);
+ *     dac.powerMode(MCP4922::DAC_A, MCP4922::POWER_NORMAL);
+ *
+ *     while (1) {
+ *         //Generate a sine wave on DAC A
+ *         for (float i = 0.0; i < 360.0; i += 0.1)
+ *             dac.write(MCP4922::DAC_A, 0.5 * (sinf(i * 3.14159265 / 180.0) + 1));
+ *     }
+ * }
+ * @endcode
+ */
+class MCP4922
+{
+public:
+    /** Represents the different DACs in the MCP4922
+     */
+    enum DAC {
+        DAC_A,              /**< DAC A */
+        DAC_B               /**< DAC B */
+    };
+
+    /** Represents the reference buffer mode of DAC A or B in the MCP4922
+     */
+    enum ReferenceMode {
+        REF_UNBUFFERED,     /**< DAC VREF is unbuffered */
+        REF_BUFFERED        /**< DAC VREF is buffered */
+    };
+
+    /** Represents the gain mode of DAC A or B in the MCP4922
+     */
+    enum GainMode {
+        GAIN_2X,            /**< DAC output = 2 * VREF * D/4096 */
+        GAIN_1X             /**< DAC output = VREF * D/4096 */
+    };
+
+    /** Represents the power mode of DAC A or B in the MCP4922
+     */
+    enum PowerMode {
+        POWER_SHUTDOWN,     /**< DAC output is high impedance */
+        POWER_NORMAL        /**< DAC output is enabled */
+    };
+
+    /** Create an MCP4922 object connected to the specified SPI pins
+     *
+     * @param mosi The SPI data out pin.
+     * @param sclk The SPI clock pin.
+     * @param cs The SPI chip select pin.
+     * @param hz The SPI bus frequency (defaults to 20MHz).
+     */
+    MCP4922(PinName mosi, PinName sclk, PinName cs, int hz = 20000000);
+
+    /** Get the current reference mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to read from.
+     *
+     * @returns The current reference mode of the specified DAC as a ReferenceMode enum.
+     */
+    MCP4922::ReferenceMode referenceMode(DAC dac);
+
+    /** Set the reference mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to write to.
+     * @param mode The new reference mode for the specified DAC as a ReferenceMode enum.
+     */
+    void referenceMode(DAC dac, ReferenceMode mode);
+
+    /** Get the current gain mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to read from.
+     *
+     * @returns The current gain mode of the specified DAC as a GainMode enum.
+     */
+    MCP4922::GainMode gainMode(DAC dac);
+
+    /** Set the gain mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to write to.
+     * @param mode The new gain mode for the specified DAC as a GainMode enum.
+     */
+    void gainMode(DAC dac, GainMode mode);
+
+    /** Get the current power mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to read from.
+     *
+     * @returns The current power mode of the specified DAC as a PowerMode enum.
+     */
+    MCP4922::PowerMode powerMode(DAC dac);
+
+    /** Set the power mode of the specified DAC in the MCP4922
+     *
+     * @param dac The DAC to write to.
+     * @param mode The new power mode for the specified DAC as a PowerMode enum.
+     */
+    void powerMode(DAC dac, PowerMode mode);
+
+    /** Get the current output voltage of the specified DAC in the MCP4922 as a percentage
+     *
+     * @param dac The DAC to read from.
+     *
+     * @returns The current output voltage of the specified DAC as a percentage (0.0 to 1.0 * VDD).
+     */
+    float read(DAC dac);
+
+    /** Set the output voltage of the specified DAC in the MCP4922 from a percentage
+     *
+     * @param dac The DAC to write to.
+     * @param value The new output voltage for the specified DAC as a percentage (0.0 to 1.0 * VDD).
+     */
+    void write(DAC dac, float value);
+
+    /** Set the output voltage of the specified DAC in the MCP4922 from a 16-bit range
+     *
+     * @param dac The DAC to write to.
+     * @param value The new output voltage for the specified DAC as a 16-bit unsigned short (0x0000 to 0xFFFF).
+     */
+    void write_u16(DAC dac, unsigned short value);
+
+private:
+    //SPI member variables
+    SPI m_SPI;
+    DigitalOut m_CS;
+
+    //DAC settings member variables
+    unsigned short m_DacValueA;
+    unsigned short m_DacValueB;
+
+    //Internal functions
+    void writeDac(unsigned short value);
+};
+
+#endif