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MCP320x_SPI.cpp
00001 /* mbed simplified access to Microchip 12 bits ADC devices (SPI) 00002 * Copyright (c) 2013 ygarcia, MIT License 00003 * 00004 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 00005 * and associated documentation files (the "Software"), to deal in the Software without restriction, 00006 * including without limitation the rights to use, copy, modify, merge, publish, distribute, 00007 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 00008 * furnished to do so, subject to the following conditions: 00009 * 00010 * The above copyright notice and this permission notice shall be included in all copies or 00011 * substantial portions of the Software. 00012 * 00013 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 00014 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 00015 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 00016 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00017 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00018 */ 00019 00020 #include "MCP320x_SPI.h" 00021 00022 namespace MCP320x_SPI { 00023 00024 unsigned char CMCP320x_SPI::SPIModuleRefCounter = 0; 00025 00026 CMCP320x_SPI::CMCP320x_SPI(const PinName p_mosi, const PinName p_miso, const PinName p_sclk, const PinName p_cs, const Mcp320xFamilly p_familly, const unsigned int p_frequency) : _internalId("") { 00027 DEBUG_ENTER("CMCP320x_SPI") 00028 00029 CMCP320x_SPI::SPIModuleRefCounter += 1; 00030 if (CMCP320x_SPI::SPIModuleRefCounter > 1) { 00031 //FIXME Check that SPI settings are identical. Otherwise it should failed 00032 return; 00033 } 00034 00035 _familly = p_familly; 00036 switch (_familly) { 00037 case _3201: 00038 _channelsNum = 1; 00039 break; 00040 case _3204: 00041 _channelsNum = 4; 00042 break; 00043 default: // _3208 00044 _channelsNum = 8; 00045 } // End of 'switch' statement 00046 _settings = 0x02; // SGL/DIFF bit set to 1 = See DS21298E-page 19 TABLE 5-1: CONFIGURATION BITS FOR THE MCP3204/TABLE 5-2: CONFIGURATION BITS FOR THE MCP3208 00047 DEBUG("CMCP320x_SPI: familly:%d - #channels:%d", _familly, _channelsNum) 00048 _spiInstance = new SPI(p_mosi, p_miso, p_sclk); 00049 _spiInstance->frequency(p_frequency); // Set the frequency of the SPI interface 00050 _spiInstance->format(8, 3); 00051 DEBUG_ENTER("CMCP320x_SPI: refCounter=%d", CMCP320x_SPI::SPIModuleRefCounter) 00052 00053 if (p_cs != NC) { 00054 DEBUG("CMCP320x_SPI: /CS managed"); 00055 _cs = new DigitalOut(p_cs); 00056 _cs->write(1); // Disable chip 00057 } else { 00058 DEBUG("CMCP320x_SPI: /CS not managed"); 00059 _cs = NULL; // Not used 00060 } 00061 00062 00063 DEBUG_LEAVE("CMCP320x_SPI") 00064 } 00065 00066 CMCP320x_SPI::~CMCP320x_SPI() { 00067 DEBUG_ENTER("~CMCP320x_SPI") 00068 00069 // Release I2C instance 00070 DEBUG_ENTER("~CMCP320x_SPI: refCounter=%d", CMCP320x_SPI::SPIModuleRefCounter) 00071 CMCP320x_SPI::SPIModuleRefCounter -= 1; 00072 if (CMCP320x_SPI::SPIModuleRefCounter == 0) { 00073 delete _spiInstance; 00074 _spiInstance = NULL; 00075 } 00076 // Release _reset if required 00077 if (_cs != NULL) { 00078 _cs->write(1); 00079 delete _cs; 00080 } 00081 00082 DEBUG_LEAVE("~CMCP320x_SPI") 00083 } 00084 00085 float CMCP320x_SPI::Read(const Mcp320xChannels p_channels) { 00086 DEBUG_ENTER("CMCP320x_SPI::Read: %d", (unsigned char)p_channels) 00087 00088 // Read a sample 00089 _sample.value = 0x00; 00090 switch (_familly) { 00091 case _3204: 00092 // No break; 00093 case _3208: 00094 Read_320x(p_channels); 00095 break; 00096 default: // _3201 00097 Read_3201(); 00098 break; 00099 } // End of 'switch' statement 00100 DEBUG("CMCP320x_SPI::Read: 0x%02x - 0x%02x", _sample.bytes[0], _sample.bytes[1]) 00101 // Convert it 00102 float temp; 00103 _sample.value >>= 1; // Adjust composite integer for 12 valid bits 00104 _sample.value &= 0x0FFF; // Mask out upper nibble of integer 00105 temp = (_sample.value * 0.001225585); 00106 00107 DEBUG_LEAVE("CMCP320x_SPI::Read: %f", temp) 00108 return temp; 00109 } 00110 00111 void CMCP320x_SPI::SetConfig(const bool p_settings) { 00112 DEBUG_LEAVE("CMCP320x_SPI::SetConfig: %x", (unsigned char)p_settings) 00113 00114 if (_settings) { 00115 _settings = 0x02; 00116 } else { 00117 _settings = 0x00; 00118 } 00119 } 00120 00121 bool CMCP320x_SPI::Shutdown(const bool p_shutdown) { 00122 // Sanity check 00123 if (_cs == NULL) { 00124 return false; 00125 } 00126 00127 _cs->write(p_shutdown == false ? 0 : 1); 00128 00129 return true; 00130 } 00131 00132 void CMCP320x_SPI::Read_3201() { 00133 if (_cs != NULL) { 00134 _cs->write(0); 00135 wait_us(1); 00136 } 00137 _sample.bytes[1] = _spiInstance->write(0); 00138 _sample.bytes[0] = _spiInstance->write(0); 00139 if (_cs != NULL) { 00140 _cs->write(1); 00141 } 00142 } 00143 00144 void CMCP320x_SPI::Read_320x(const Mcp320xChannels p_channels) { 00145 DEBUG_ENTER("CMCP320x_SPI::Read_320x: %d", (unsigned char)p_channels) 00146 00147 unsigned char _channels = (unsigned char)p_channels % _channelsNum; 00148 // Set start bit 00149 unsigned char mask = 0x04 | _settings; // Start bit set to 1 - See DS21298E-page 19 Clause 5.0 SERIAL COMMUNICATIONS 00150 // Set channel address 00151 unsigned char cmd0; 00152 unsigned char cmd1; 00153 if (_familly == _3204) { 00154 cmd0 = mask; 00155 cmd1 = _channels << 6; // MCP3204 has 4 channels in single-ended mode 00156 } else { // MCP3208 00157 cmd0 = mask | ((_channels & 0x04) >> 2); // Extract D2 bit - See DS21298E-page 19 Clause 5.0 SERIAL COMMUNICATIONS 00158 cmd1 = _channels << 6; // MCP3204 has 8 channels in single-ended mode 00159 } 00160 DEBUG("CMCP320x_SPI::Read_320x: cmd0:%02x - cmd1:%02x", cmd0, cmd1) 00161 if (_cs != NULL) { 00162 _cs->write(0); 00163 wait_us(1); 00164 } 00165 _spiInstance->write(cmd0); // Don't care of the result - See DS21298E-page 21 Clause 6.1 Using the MCP3204/3208 with Microcontroller (MCU) SPI Ports 00166 _sample.bytes[1] = _spiInstance->write(cmd1); // DS21298E-page 21 See FIGURE 6-1: SPI Communication using 8-bit segments (Mode 0,0: SCLK idles low) 00167 _sample.bytes[0] = _spiInstance->write(0); 00168 if (_cs != NULL) { 00169 _cs->write(1); 00170 } 00171 00172 DEBUG_LEAVE("CMCP320x_SPI::Read_320x") 00173 } 00174 00175 } // End of namespace MCP320x_SPI
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