Neil Thiessen / MCP4922

A feature complete driver for the MCP4922 DAC from Microchip.

Dependents:   MCP4922_HelloWorld NuMidi401 NuFM401 NuFM402

MCP4922.cpp@0:e994c6963c66, 2014-05-15 (annotated)

Committer:
neilt6
Date:
Thu May 15 17:33:40 2014 +0000
Revision:
0:e994c6963c66
Child:
1:747ec9c5d80e
Initial commit

Who changed what in which revision?

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neilt6 0:e994c6963c66 1 /* MCP4922 Driver Library
neilt6 0:e994c6963c66 2 * Copyright (c) 2014 Neil Thiessen
neilt6 0:e994c6963c66 3 *
neilt6 0:e994c6963c66 4 * Licensed under the Apache License, Version 2.0 (the "License");
neilt6 0:e994c6963c66 5 * you may not use this file except in compliance with the License.
neilt6 0:e994c6963c66 6 * You may obtain a copy of the License at
neilt6 0:e994c6963c66 7 *
neilt6 0:e994c6963c66 8 * http://www.apache.org/licenses/LICENSE-2.0
neilt6 0:e994c6963c66 9 *
neilt6 0:e994c6963c66 10 * Unless required by applicable law or agreed to in writing, software
neilt6 0:e994c6963c66 11 * distributed under the License is distributed on an "AS IS" BASIS,
neilt6 0:e994c6963c66 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
neilt6 0:e994c6963c66 13 * See the License for the specific language governing permissions and
neilt6 0:e994c6963c66 14 * limitations under the License.
neilt6 0:e994c6963c66 15 */
neilt6 0:e994c6963c66 16
neilt6 0:e994c6963c66 17 #include "MCP4922.h"
neilt6 0:e994c6963c66 18
neilt6 0:e994c6963c66 19 MCP4922::MCP4922(PinName mosi, PinName sclk, PinName cs, int hz) : m_SPI(mosi, NC, sclk), m_CS(cs, 1)
neilt6 0:e994c6963c66 20 {
neilt6 0:e994c6963c66 21 //Set the SPI format and bus frequency
neilt6 0:e994c6963c66 22 m_SPI.format(16, 0);
neilt6 0:e994c6963c66 23 m_SPI.frequency(hz);
neilt6 0:e994c6963c66 24 }
neilt6 0:e994c6963c66 25
neilt6 0:e994c6963c66 26 MCP4922::ReferenceMode MCP4922::referenceMode(DAC dac)
neilt6 0:e994c6963c66 27 {
neilt6 0:e994c6963c66 28 //Return the current reference mode for the specified DAC
neilt6 0:e994c6963c66 29 if (dac == DAC_A)
neilt6 0:e994c6963c66 30 return (ReferenceMode)((m_DacValueA >> 14) & 0x01);
neilt6 0:e994c6963c66 31 else
neilt6 0:e994c6963c66 32 return (ReferenceMode)((m_DacValueB >> 14) & 0x01);
neilt6 0:e994c6963c66 33 }
neilt6 0:e994c6963c66 34
neilt6 0:e994c6963c66 35 void MCP4922::referenceMode(DAC dac, ReferenceMode mode)
neilt6 0:e994c6963c66 36 {
neilt6 0:e994c6963c66 37 //Update the reference mode for the specified DAC
neilt6 0:e994c6963c66 38 if (dac == DAC_A) {
neilt6 0:e994c6963c66 39 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 40 m_DacValueA &= ~(1 << 14);
neilt6 0:e994c6963c66 41 m_DacValueA |= (mode << 14);
neilt6 0:e994c6963c66 42
neilt6 0:e994c6963c66 43 //Update the DAC A
neilt6 0:e994c6963c66 44 writeDac(m_DacValueA | (dac << 15));
neilt6 0:e994c6963c66 45 } else {
neilt6 0:e994c6963c66 46 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 47 m_DacValueB &= ~(1 << 14);
neilt6 0:e994c6963c66 48 m_DacValueB |= (mode << 14);
neilt6 0:e994c6963c66 49
neilt6 0:e994c6963c66 50 //Update the DAC B
neilt6 0:e994c6963c66 51 writeDac(m_DacValueB | (dac << 15));
neilt6 0:e994c6963c66 52 }
neilt6 0:e994c6963c66 53 }
neilt6 0:e994c6963c66 54
neilt6 0:e994c6963c66 55 MCP4922::GainMode MCP4922::gainMode(DAC dac)
neilt6 0:e994c6963c66 56 {
neilt6 0:e994c6963c66 57 //Return the current gain mode for the specified DAC
neilt6 0:e994c6963c66 58 if (dac == DAC_A)
neilt6 0:e994c6963c66 59 return (GainMode)((m_DacValueA >> 13) & 0x01);
neilt6 0:e994c6963c66 60 else
neilt6 0:e994c6963c66 61 return (GainMode)((m_DacValueB >> 13) & 0x01);
neilt6 0:e994c6963c66 62 }
neilt6 0:e994c6963c66 63
neilt6 0:e994c6963c66 64 void MCP4922::gainMode(DAC dac, GainMode mode)
neilt6 0:e994c6963c66 65 {
neilt6 0:e994c6963c66 66 //Update the gain mode for the specified DAC
neilt6 0:e994c6963c66 67 if (dac == DAC_A) {
neilt6 0:e994c6963c66 68 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 69 m_DacValueA &= ~(1 << 13);
neilt6 0:e994c6963c66 70 m_DacValueA |= (mode << 13);
neilt6 0:e994c6963c66 71
neilt6 0:e994c6963c66 72 //Update the DAC A
neilt6 0:e994c6963c66 73 writeDac(m_DacValueA | (dac << 15));
neilt6 0:e994c6963c66 74 } else {
neilt6 0:e994c6963c66 75 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 76 m_DacValueB &= ~(1 << 13);
neilt6 0:e994c6963c66 77 m_DacValueB |= (mode << 13);
neilt6 0:e994c6963c66 78
neilt6 0:e994c6963c66 79 //Update the DAC B
neilt6 0:e994c6963c66 80 writeDac(m_DacValueB | (dac << 15));
neilt6 0:e994c6963c66 81 }
neilt6 0:e994c6963c66 82 }
neilt6 0:e994c6963c66 83
neilt6 0:e994c6963c66 84 MCP4922::PowerMode MCP4922::powerMode(DAC dac)
neilt6 0:e994c6963c66 85 {
neilt6 0:e994c6963c66 86 //Return the current power mode for the specified DAC
neilt6 0:e994c6963c66 87 if (dac == DAC_A)
neilt6 0:e994c6963c66 88 return (PowerMode)((m_DacValueA >> 12) & 0x01);
neilt6 0:e994c6963c66 89 else
neilt6 0:e994c6963c66 90 return (PowerMode)((m_DacValueB >> 12) & 0x01);
neilt6 0:e994c6963c66 91 }
neilt6 0:e994c6963c66 92
neilt6 0:e994c6963c66 93 void MCP4922::powerMode(DAC dac, PowerMode mode)
neilt6 0:e994c6963c66 94 {
neilt6 0:e994c6963c66 95 //Update the power mode for the specified DAC
neilt6 0:e994c6963c66 96 if (dac == DAC_A) {
neilt6 0:e994c6963c66 97 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 98 m_DacValueA &= ~(1 << 12);
neilt6 0:e994c6963c66 99 m_DacValueA |= (mode << 12);
neilt6 0:e994c6963c66 100
neilt6 0:e994c6963c66 101 //Update the DAC A
neilt6 0:e994c6963c66 102 writeDac(m_DacValueA | (dac << 15));
neilt6 0:e994c6963c66 103 } else {
neilt6 0:e994c6963c66 104 //Mask off the old mode, and set the new one
neilt6 0:e994c6963c66 105 m_DacValueB &= ~(1 << 12);
neilt6 0:e994c6963c66 106 m_DacValueB |= (mode << 12);
neilt6 0:e994c6963c66 107
neilt6 0:e994c6963c66 108 //Update the DAC B
neilt6 0:e994c6963c66 109 writeDac(m_DacValueB | (dac << 15));
neilt6 0:e994c6963c66 110 }
neilt6 0:e994c6963c66 111 }
neilt6 0:e994c6963c66 112
neilt6 0:e994c6963c66 113 float MCP4922::read(DAC dac)
neilt6 0:e994c6963c66 114 {
neilt6 0:e994c6963c66 115 //Return the current value for the specified DAC as a float
neilt6 0:e994c6963c66 116 if (dac == DAC_A)
neilt6 0:e994c6963c66 117 return (m_DacValueA & 0x0FFF) / 4095.0;
neilt6 0:e994c6963c66 118 else
neilt6 0:e994c6963c66 119 return (m_DacValueB & 0x0FFF) / 4095.0;
neilt6 0:e994c6963c66 120 }
neilt6 0:e994c6963c66 121
neilt6 0:e994c6963c66 122 void MCP4922::write(DAC dac, float value)
neilt6 0:e994c6963c66 123 {
neilt6 0:e994c6963c66 124 //Range limit value
neilt6 0:e994c6963c66 125 if (value < 0.0)
neilt6 0:e994c6963c66 126 value = 0.0;
neilt6 0:e994c6963c66 127 else if (value > 1.0)
neilt6 0:e994c6963c66 128 value = 1.0;
neilt6 0:e994c6963c66 129
neilt6 0:e994c6963c66 130 //Convert value to an unsigned short, and pass it to write_u16()
neilt6 0:e994c6963c66 131 write_u16(dac, (unsigned short)(value * 4095) << 4);
neilt6 0:e994c6963c66 132 }
neilt6 0:e994c6963c66 133
neilt6 0:e994c6963c66 134 void MCP4922::write_u16(DAC dac, unsigned short value)
neilt6 0:e994c6963c66 135 {
neilt6 0:e994c6963c66 136 //Update the value for the specified DAC
neilt6 0:e994c6963c66 137 if (dac == DAC_A) {
neilt6 0:e994c6963c66 138 //Mask off the old value, and set the new one
neilt6 0:e994c6963c66 139 m_DacValueA &= 0xF000;
neilt6 0:e994c6963c66 140 m_DacValueA |= value >> 4;
neilt6 0:e994c6963c66 141
neilt6 0:e994c6963c66 142 //Update the DAC A
neilt6 0:e994c6963c66 143 writeDac(m_DacValueA | (dac << 15));
neilt6 0:e994c6963c66 144 } else {
neilt6 0:e994c6963c66 145 //Mask off the old value, and set the new one
neilt6 0:e994c6963c66 146 m_DacValueB &= 0xF000;
neilt6 0:e994c6963c66 147 m_DacValueB |= value >> 4;
neilt6 0:e994c6963c66 148
neilt6 0:e994c6963c66 149 //Update the DAC B
neilt6 0:e994c6963c66 150 writeDac(m_DacValueB | (dac << 15));
neilt6 0:e994c6963c66 151 }
neilt6 0:e994c6963c66 152 }
neilt6 0:e994c6963c66 153
neilt6 0:e994c6963c66 154 void MCP4922::writeDac(unsigned short value)
neilt6 0:e994c6963c66 155 {
neilt6 0:e994c6963c66 156 //Pull CS low
neilt6 0:e994c6963c66 157 m_CS = 0;
neilt6 0:e994c6963c66 158
neilt6 0:e994c6963c66 159 //Perform the 16-bit write
neilt6 0:e994c6963c66 160 m_SPI.write(value);
neilt6 0:e994c6963c66 161
neilt6 0:e994c6963c66 162 //Pull CS high
neilt6 0:e994c6963c66 163 m_CS = 1;
neilt6 0:e994c6963c66 164 }