Diff: MCP4922.cpp

Revision:

0:e994c6963c66

Child:

1:747ec9c5d80e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP4922.cpp	Thu May 15 17:33:40 2014 +0000
@@ -0,0 +1,164 @@
+/* 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.
+ */
+
+#include "MCP4922.h"
+
+MCP4922::MCP4922(PinName mosi, PinName sclk, PinName cs, int hz) : m_SPI(mosi, NC, sclk), m_CS(cs, 1)
+{
+    //Set the SPI format and bus frequency
+    m_SPI.format(16, 0);
+    m_SPI.frequency(hz);
+}
+
+MCP4922::ReferenceMode MCP4922::referenceMode(DAC dac)
+{
+    //Return the current reference mode for the specified DAC
+    if (dac == DAC_A)
+        return (ReferenceMode)((m_DacValueA >> 14) & 0x01);
+    else
+        return (ReferenceMode)((m_DacValueB >> 14) & 0x01);
+}
+
+void MCP4922::referenceMode(DAC dac, ReferenceMode mode)
+{
+    //Update the reference mode for the specified DAC
+    if (dac == DAC_A) {
+        //Mask off the old mode, and set the new one
+        m_DacValueA &= ~(1 << 14);
+        m_DacValueA |= (mode << 14);
+
+        //Update the DAC A
+        writeDac(m_DacValueA | (dac << 15));
+    } else {
+        //Mask off the old mode, and set the new one
+        m_DacValueB &= ~(1 << 14);
+        m_DacValueB |= (mode << 14);
+
+        //Update the DAC B
+        writeDac(m_DacValueB | (dac << 15));
+    }
+}
+
+MCP4922::GainMode MCP4922::gainMode(DAC dac)
+{
+    //Return the current gain mode for the specified DAC
+    if (dac == DAC_A)
+        return (GainMode)((m_DacValueA >> 13) & 0x01);
+    else
+        return (GainMode)((m_DacValueB >> 13) & 0x01);
+}
+
+void MCP4922::gainMode(DAC dac, GainMode mode)
+{
+    //Update the gain mode for the specified DAC
+    if (dac == DAC_A) {
+        //Mask off the old mode, and set the new one
+        m_DacValueA &= ~(1 << 13);
+        m_DacValueA |= (mode << 13);
+
+        //Update the DAC A
+        writeDac(m_DacValueA | (dac << 15));
+    } else {
+        //Mask off the old mode, and set the new one
+        m_DacValueB &= ~(1 << 13);
+        m_DacValueB |= (mode << 13);
+
+        //Update the DAC B
+        writeDac(m_DacValueB | (dac << 15));
+    }
+}
+
+MCP4922::PowerMode MCP4922::powerMode(DAC dac)
+{
+    //Return the current power mode for the specified DAC
+    if (dac == DAC_A)
+        return (PowerMode)((m_DacValueA >> 12) & 0x01);
+    else
+        return (PowerMode)((m_DacValueB >> 12) & 0x01);
+}
+
+void MCP4922::powerMode(DAC dac, PowerMode mode)
+{
+    //Update the power mode for the specified DAC
+    if (dac == DAC_A) {
+        //Mask off the old mode, and set the new one
+        m_DacValueA &= ~(1 << 12);
+        m_DacValueA |= (mode << 12);
+
+        //Update the DAC A
+        writeDac(m_DacValueA | (dac << 15));
+    } else {
+        //Mask off the old mode, and set the new one
+        m_DacValueB &= ~(1 << 12);
+        m_DacValueB |= (mode << 12);
+
+        //Update the DAC B
+        writeDac(m_DacValueB | (dac << 15));
+    }
+}
+
+float MCP4922::read(DAC dac)
+{
+    //Return the current value for the specified DAC as a float
+    if (dac == DAC_A)
+        return (m_DacValueA & 0x0FFF) / 4095.0;
+    else
+        return (m_DacValueB & 0x0FFF) / 4095.0;
+}
+
+void MCP4922::write(DAC dac, float value)
+{
+    //Range limit value
+    if (value < 0.0)
+        value = 0.0;
+    else if (value > 1.0)
+        value = 1.0;
+
+    //Convert value to an unsigned short, and pass it to write_u16()
+    write_u16(dac, (unsigned short)(value * 4095) << 4);
+}
+
+void MCP4922::write_u16(DAC dac, unsigned short value)
+{
+    //Update the value for the specified DAC
+    if (dac == DAC_A) {
+        //Mask off the old value, and set the new one
+        m_DacValueA &= 0xF000;
+        m_DacValueA |= value >> 4;
+
+        //Update the DAC A
+        writeDac(m_DacValueA | (dac << 15));
+    } else {
+        //Mask off the old value, and set the new one
+        m_DacValueB &= 0xF000;
+        m_DacValueB |= value >> 4;
+
+        //Update the DAC B
+        writeDac(m_DacValueB | (dac << 15));
+    }
+}
+
+void MCP4922::writeDac(unsigned short value)
+{
+    //Pull CS low
+    m_CS = 0;
+
+    //Perform the 16-bit write
+    m_SPI.write(value);
+
+    //Pull CS high
+    m_CS = 1;
+}