12-Bit DAC with internal Vref and SPI interface
MCP4822.cpp
- Committer:
- stjo2809
- Date:
- 2015-03-23
- Revision:
- 0:929babff65b1
File content as of revision 0:929babff65b1:
/* mbed MCP4822 Library, for driving the 12-Bit DAC with internal Vref and SPI interface * Copyright (c) 2015, Created by Steen Joergensen (stjo2809) * * 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 "MCP4822.h" //============================================================================= // Public functions //============================================================================= MCP4822::MCP4822(SPI& spi, PinName nLDAC, PinName nCs) : _spi(spi), _nLDAC(nLDAC), _nCs(nCs) { } MCP4822::MCP4822(PinName nLDAC, PinName mosi, PinName miso,PinName sck, PinName nCs) : _nLDAC(nLDAC), _mosi(mosi), _miso(miso), _sck(sck), _nCs(nCs) { SPI _spi(_mosi,_miso,_sck); } void MCP4822::a(bool gain, int data) { _write(0, gain, 1, data); } void MCP4822::b(bool gain, int data) { _write(1, gain, 1, data); } void MCP4822::ldac(bool act) { _nLDAC = ~act; } void MCP4822::shdn(bool output, bool act) { _write(output, 1, ~act, 0x00); } //============================================================================= // Private functions //============================================================================= char MCP4822::_make_upper_half(bool output, bool gain, bool shdn, int data) { char responce = 0; if(output == '0') { responce = responce | CB_OUTPUT_A; } else { responce = responce | CB_OUTPUT_B; } if(gain == '0') { responce = responce | CB_GAIN_2X; } else { responce = responce | CB_GAIN_1X; } if(shdn == '0') { responce = responce | CB_NSHDN; } else { responce = responce | CB_SHDN; } if(data > 0xff && data < 0xfff) { responce = responce | (data >> 8); } return responce; } char MCP4822::_make_lower_half(int data) { return (data & 0xff); } void MCP4822::_write(bool output, bool gain, bool shdn, int data) { _upper_half = _make_upper_half(output, gain, shdn, data); _lower_half = _make_lower_half(data); _nCs = 0; _spi.write(_upper_half); _spi.write(_lower_half); _nCs = 1; }