A feature complete driver for the MCP4725 DAC from Microchip with an AnalogOut-compatible API.
Dependents: MCP4725_HelloWorld DAC02_RFID_and_TFT
MCP4725.cpp@2:42d9d780813b, 2014-05-30 (annotated)
- Committer:
- neilt6
- Date:
- Fri May 30 18:57:36 2014 +0000
- Revision:
- 2:42d9d780813b
- Parent:
- 1:3b687a9acdf3
Added MBED_OPERATORS check to implementation
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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neilt6 | 0:203cdd3b30fc | 1 | /* MCP4725 Driver Library |
neilt6 | 0:203cdd3b30fc | 2 | * Copyright (c) 2014 Neil Thiessen |
neilt6 | 0:203cdd3b30fc | 3 | * |
neilt6 | 0:203cdd3b30fc | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
neilt6 | 0:203cdd3b30fc | 5 | * you may not use this file except in compliance with the License. |
neilt6 | 0:203cdd3b30fc | 6 | * You may obtain a copy of the License at |
neilt6 | 0:203cdd3b30fc | 7 | * |
neilt6 | 0:203cdd3b30fc | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
neilt6 | 0:203cdd3b30fc | 9 | * |
neilt6 | 0:203cdd3b30fc | 10 | * Unless required by applicable law or agreed to in writing, software |
neilt6 | 0:203cdd3b30fc | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
neilt6 | 0:203cdd3b30fc | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
neilt6 | 0:203cdd3b30fc | 13 | * See the License for the specific language governing permissions and |
neilt6 | 0:203cdd3b30fc | 14 | * limitations under the License. |
neilt6 | 0:203cdd3b30fc | 15 | */ |
neilt6 | 0:203cdd3b30fc | 16 | |
neilt6 | 0:203cdd3b30fc | 17 | #include "MCP4725.h" |
neilt6 | 0:203cdd3b30fc | 18 | |
neilt6 | 0:203cdd3b30fc | 19 | MCP4725::MCP4725(PinName sda, PinName scl, Address addr, int hz) : m_I2C(sda, scl), m_ADDR((int)addr) |
neilt6 | 0:203cdd3b30fc | 20 | { |
neilt6 | 0:203cdd3b30fc | 21 | //Set the I2C bus frequency |
neilt6 | 0:203cdd3b30fc | 22 | m_I2C.frequency(hz); |
neilt6 | 0:203cdd3b30fc | 23 | } |
neilt6 | 0:203cdd3b30fc | 24 | |
neilt6 | 0:203cdd3b30fc | 25 | bool MCP4725::open() |
neilt6 | 0:203cdd3b30fc | 26 | { |
neilt6 | 0:203cdd3b30fc | 27 | //Probe for the MCP4725 using a Zero Length Transfer |
neilt6 | 0:203cdd3b30fc | 28 | if (!m_I2C.write(m_ADDR, NULL, 0)) { |
neilt6 | 0:203cdd3b30fc | 29 | //Return success |
neilt6 | 0:203cdd3b30fc | 30 | return true; |
neilt6 | 0:203cdd3b30fc | 31 | } else { |
neilt6 | 0:203cdd3b30fc | 32 | //Return failure |
neilt6 | 0:203cdd3b30fc | 33 | return false; |
neilt6 | 0:203cdd3b30fc | 34 | } |
neilt6 | 0:203cdd3b30fc | 35 | } |
neilt6 | 0:203cdd3b30fc | 36 | |
neilt6 | 0:203cdd3b30fc | 37 | void MCP4725::reset() |
neilt6 | 0:203cdd3b30fc | 38 | { |
neilt6 | 0:203cdd3b30fc | 39 | //The General Call Reset command |
neilt6 | 0:203cdd3b30fc | 40 | char data = 0x06; |
neilt6 | 0:203cdd3b30fc | 41 | |
neilt6 | 0:203cdd3b30fc | 42 | //Issue the command to the General Call address |
neilt6 | 0:203cdd3b30fc | 43 | m_I2C.write(0x00, &data, 1); |
neilt6 | 0:203cdd3b30fc | 44 | } |
neilt6 | 0:203cdd3b30fc | 45 | |
neilt6 | 0:203cdd3b30fc | 46 | void MCP4725::wakeup() |
neilt6 | 0:203cdd3b30fc | 47 | { |
neilt6 | 0:203cdd3b30fc | 48 | //The General Call Wake-up command |
neilt6 | 0:203cdd3b30fc | 49 | char data = 0x09; |
neilt6 | 0:203cdd3b30fc | 50 | |
neilt6 | 0:203cdd3b30fc | 51 | //Issue the command to the General Call address |
neilt6 | 0:203cdd3b30fc | 52 | m_I2C.write(0x00, &data, 1); |
neilt6 | 0:203cdd3b30fc | 53 | } |
neilt6 | 0:203cdd3b30fc | 54 | |
neilt6 | 0:203cdd3b30fc | 55 | MCP4725::PowerMode MCP4725::powerMode() |
neilt6 | 0:203cdd3b30fc | 56 | { |
neilt6 | 0:203cdd3b30fc | 57 | //Read the current settings from the DAC |
neilt6 | 0:203cdd3b30fc | 58 | readDac(); |
neilt6 | 0:203cdd3b30fc | 59 | |
neilt6 | 0:203cdd3b30fc | 60 | //Return the current power mode |
neilt6 | 0:203cdd3b30fc | 61 | return m_PowerMode; |
neilt6 | 0:203cdd3b30fc | 62 | } |
neilt6 | 0:203cdd3b30fc | 63 | |
neilt6 | 0:203cdd3b30fc | 64 | void MCP4725::powerMode(PowerMode mode) |
neilt6 | 0:203cdd3b30fc | 65 | { |
neilt6 | 0:203cdd3b30fc | 66 | //Update the power mode |
neilt6 | 0:203cdd3b30fc | 67 | m_PowerMode = mode; |
neilt6 | 0:203cdd3b30fc | 68 | |
neilt6 | 0:203cdd3b30fc | 69 | //Update the DAC |
neilt6 | 0:203cdd3b30fc | 70 | writeDac(); |
neilt6 | 0:203cdd3b30fc | 71 | } |
neilt6 | 0:203cdd3b30fc | 72 | |
neilt6 | 0:203cdd3b30fc | 73 | float MCP4725::read() |
neilt6 | 0:203cdd3b30fc | 74 | { |
neilt6 | 0:203cdd3b30fc | 75 | //Read the current settings from the DAC |
neilt6 | 0:203cdd3b30fc | 76 | readDac(); |
neilt6 | 0:203cdd3b30fc | 77 | |
neilt6 | 0:203cdd3b30fc | 78 | //Return the current DAC value as a percentage |
neilt6 | 0:203cdd3b30fc | 79 | return m_DacValue / 4095.0; |
neilt6 | 0:203cdd3b30fc | 80 | } |
neilt6 | 0:203cdd3b30fc | 81 | |
neilt6 | 0:203cdd3b30fc | 82 | void MCP4725::write(float value) |
neilt6 | 0:203cdd3b30fc | 83 | { |
neilt6 | 0:203cdd3b30fc | 84 | //Range limit value |
neilt6 | 0:203cdd3b30fc | 85 | if (value < 0.0) |
neilt6 | 0:203cdd3b30fc | 86 | value = 0.0; |
neilt6 | 0:203cdd3b30fc | 87 | else if (value > 1.0) |
neilt6 | 0:203cdd3b30fc | 88 | value = 1.0; |
neilt6 | 0:203cdd3b30fc | 89 | |
neilt6 | 0:203cdd3b30fc | 90 | //Update the DAC value |
neilt6 | 0:203cdd3b30fc | 91 | m_DacValue = (unsigned short)(value * 4095); |
neilt6 | 0:203cdd3b30fc | 92 | |
neilt6 | 0:203cdd3b30fc | 93 | //Update the DAC |
neilt6 | 0:203cdd3b30fc | 94 | writeDac(); |
neilt6 | 0:203cdd3b30fc | 95 | } |
neilt6 | 0:203cdd3b30fc | 96 | |
neilt6 | 0:203cdd3b30fc | 97 | void MCP4725::write_u16(unsigned short value) |
neilt6 | 0:203cdd3b30fc | 98 | { |
neilt6 | 0:203cdd3b30fc | 99 | //Update the DAC value |
neilt6 | 0:203cdd3b30fc | 100 | m_DacValue = value >> 4; |
neilt6 | 0:203cdd3b30fc | 101 | |
neilt6 | 0:203cdd3b30fc | 102 | //Update the DAC |
neilt6 | 0:203cdd3b30fc | 103 | writeDac(); |
neilt6 | 0:203cdd3b30fc | 104 | } |
neilt6 | 0:203cdd3b30fc | 105 | |
neilt6 | 0:203cdd3b30fc | 106 | void MCP4725::readEeprom(PowerMode* mode, unsigned short* value) |
neilt6 | 0:203cdd3b30fc | 107 | { |
neilt6 | 0:203cdd3b30fc | 108 | //Create a temporary buffer |
neilt6 | 0:203cdd3b30fc | 109 | char buff[5]; |
neilt6 | 0:203cdd3b30fc | 110 | |
neilt6 | 0:203cdd3b30fc | 111 | //Keep reading until the EEPROM is ready |
neilt6 | 0:203cdd3b30fc | 112 | do { |
neilt6 | 0:203cdd3b30fc | 113 | m_I2C.read(m_ADDR, buff, 5); |
neilt6 | 0:203cdd3b30fc | 114 | } while ((buff[0] & 0x80) == 0); |
neilt6 | 0:203cdd3b30fc | 115 | |
neilt6 | 0:203cdd3b30fc | 116 | //Extract the EEPROM power mode, and 12-bit DAC value |
neilt6 | 0:203cdd3b30fc | 117 | *mode = (PowerMode)((buff[3] >> 5) & 0x03); |
neilt6 | 0:203cdd3b30fc | 118 | *value = ((buff[3] << 8) & 0xFFF) | buff[4]; |
neilt6 | 0:203cdd3b30fc | 119 | } |
neilt6 | 0:203cdd3b30fc | 120 | |
neilt6 | 0:203cdd3b30fc | 121 | void MCP4725::writeEeprom(PowerMode mode, unsigned short value) |
neilt6 | 0:203cdd3b30fc | 122 | { |
neilt6 | 0:203cdd3b30fc | 123 | //Create a temporary buffer |
neilt6 | 0:203cdd3b30fc | 124 | char buff[5]; |
neilt6 | 0:203cdd3b30fc | 125 | |
neilt6 | 0:203cdd3b30fc | 126 | //Block until the EEPROM is ready |
neilt6 | 0:203cdd3b30fc | 127 | do { |
neilt6 | 0:203cdd3b30fc | 128 | m_I2C.read(m_ADDR, buff, 5); |
neilt6 | 0:203cdd3b30fc | 129 | } while ((buff[0] & 0x80) == 0); |
neilt6 | 0:203cdd3b30fc | 130 | |
neilt6 | 0:203cdd3b30fc | 131 | //Load the command, power mode, and 12-bit DAC value |
neilt6 | 0:203cdd3b30fc | 132 | buff[0] = 0x60 | ((int)mode << 1); |
neilt6 | 0:203cdd3b30fc | 133 | buff[1] = value >> 4; |
neilt6 | 0:203cdd3b30fc | 134 | buff[2] = value << 4; |
neilt6 | 0:203cdd3b30fc | 135 | |
neilt6 | 0:203cdd3b30fc | 136 | //Write the data |
neilt6 | 0:203cdd3b30fc | 137 | m_I2C.write(m_ADDR, buff, 3); |
neilt6 | 0:203cdd3b30fc | 138 | } |
neilt6 | 0:203cdd3b30fc | 139 | |
neilt6 | 2:42d9d780813b | 140 | #ifdef MBED_OPERATORS |
neilt6 | 0:203cdd3b30fc | 141 | MCP4725::operator float() |
neilt6 | 0:203cdd3b30fc | 142 | { |
neilt6 | 0:203cdd3b30fc | 143 | //Return the current output voltage |
neilt6 | 0:203cdd3b30fc | 144 | return read(); |
neilt6 | 0:203cdd3b30fc | 145 | } |
neilt6 | 0:203cdd3b30fc | 146 | |
neilt6 | 0:203cdd3b30fc | 147 | MCP4725& MCP4725::operator=(float value) |
neilt6 | 0:203cdd3b30fc | 148 | { |
neilt6 | 0:203cdd3b30fc | 149 | //Set the output voltage |
neilt6 | 0:203cdd3b30fc | 150 | write(value); |
neilt6 | 0:203cdd3b30fc | 151 | return *this; |
neilt6 | 0:203cdd3b30fc | 152 | } |
neilt6 | 2:42d9d780813b | 153 | #endif |
neilt6 | 0:203cdd3b30fc | 154 | |
neilt6 | 0:203cdd3b30fc | 155 | void MCP4725::readDac() |
neilt6 | 0:203cdd3b30fc | 156 | { |
neilt6 | 0:203cdd3b30fc | 157 | //Create a temporary buffer |
neilt6 | 0:203cdd3b30fc | 158 | char buff[5]; |
neilt6 | 0:203cdd3b30fc | 159 | |
neilt6 | 0:203cdd3b30fc | 160 | //Read the current DAC settings |
neilt6 | 0:203cdd3b30fc | 161 | m_I2C.read(m_ADDR, buff, 5); |
neilt6 | 0:203cdd3b30fc | 162 | |
neilt6 | 0:203cdd3b30fc | 163 | //Extract the current power mode, and 12-bit DAC value |
neilt6 | 0:203cdd3b30fc | 164 | m_PowerMode = (PowerMode)((buff[0] >> 1) & 0x03); |
neilt6 | 0:203cdd3b30fc | 165 | m_DacValue = (buff[1] << 4) | (buff[2] >> 4); |
neilt6 | 0:203cdd3b30fc | 166 | } |
neilt6 | 0:203cdd3b30fc | 167 | |
neilt6 | 0:203cdd3b30fc | 168 | void MCP4725::writeDac() |
neilt6 | 0:203cdd3b30fc | 169 | { |
neilt6 | 0:203cdd3b30fc | 170 | //Create a temporary buffer |
neilt6 | 0:203cdd3b30fc | 171 | char buff[2]; |
neilt6 | 0:203cdd3b30fc | 172 | |
neilt6 | 0:203cdd3b30fc | 173 | //Load the power mode, and 12-bit DAC value |
neilt6 | 0:203cdd3b30fc | 174 | buff[0] = ((int)m_PowerMode << 4) | (m_DacValue >> 8); |
neilt6 | 0:203cdd3b30fc | 175 | buff[1] = m_DacValue; |
neilt6 | 0:203cdd3b30fc | 176 | |
neilt6 | 0:203cdd3b30fc | 177 | //Write the data |
neilt6 | 0:203cdd3b30fc | 178 | m_I2C.write(m_ADDR, buff, 2); |
neilt6 | 0:203cdd3b30fc | 179 | } |