A component library for MiCS-6814 Multichannel Gas Sensor (seeed)
Dependents: MiCS6814_GasSensor_Hello grove_multichannel_GasSensor
multigas_sensor.cpp@0:e0794665caf1, 2017-05-24 (annotated)
- Committer:
- edamame22
- Date:
- Wed May 24 01:43:23 2017 +0000
- Revision:
- 0:e0794665caf1
Initial commit
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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edamame22 | 0:e0794665caf1 | 1 | /** |
edamame22 | 0:e0794665caf1 | 2 | ****************************************************************************** |
edamame22 | 0:e0794665caf1 | 3 | * @file multigas_sensor.cpp |
edamame22 | 0:e0794665caf1 | 4 | * @author Boting Ren |
edamame22 | 0:e0794665caf1 | 5 | * @version V1.0.1 |
edamame22 | 0:e0794665caf1 | 6 | * @date 22 May 2017 |
edamame22 | 0:e0794665caf1 | 7 | * @brief MiCS6814_GasSensor class implementation |
edamame22 | 0:e0794665caf1 | 8 | ****************************************************************************** |
edamame22 | 0:e0794665caf1 | 9 | * @attention |
edamame22 | 0:e0794665caf1 | 10 | * |
edamame22 | 0:e0794665caf1 | 11 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
edamame22 | 0:e0794665caf1 | 12 | * of this software and associated documentation files (the "Software"), to deal |
edamame22 | 0:e0794665caf1 | 13 | * in the Software without restriction, including without limitation the rights |
edamame22 | 0:e0794665caf1 | 14 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
edamame22 | 0:e0794665caf1 | 15 | * copies of the Software, and to permit persons to whom the Software is |
edamame22 | 0:e0794665caf1 | 16 | * furnished to do so, subject to the following conditions: |
edamame22 | 0:e0794665caf1 | 17 | * |
edamame22 | 0:e0794665caf1 | 18 | * The above copyright notice and this permission notice shall be included in |
edamame22 | 0:e0794665caf1 | 19 | * all copies or substantial portions of the Software. |
edamame22 | 0:e0794665caf1 | 20 | * |
edamame22 | 0:e0794665caf1 | 21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
edamame22 | 0:e0794665caf1 | 22 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
edamame22 | 0:e0794665caf1 | 23 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
edamame22 | 0:e0794665caf1 | 24 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
edamame22 | 0:e0794665caf1 | 25 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
edamame22 | 0:e0794665caf1 | 26 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
edamame22 | 0:e0794665caf1 | 27 | * THE SOFTWARE. |
edamame22 | 0:e0794665caf1 | 28 | * |
edamame22 | 0:e0794665caf1 | 29 | * @par History |
edamame22 | 0:e0794665caf1 | 30 | * - 19 May 2017, V1.0.0, Boting Ren |
edamame22 | 0:e0794665caf1 | 31 | * - 22 May 2017, V1.0.1, Boting Ren |
edamame22 | 0:e0794665caf1 | 32 | * 1. changed class name and private variables name |
edamame22 | 0:e0794665caf1 | 33 | * 2. removed printf output |
edamame22 | 0:e0794665caf1 | 34 | * 3. removed removed timer and Cache feature |
edamame22 | 0:e0794665caf1 | 35 | * 4. removed code working for version 1 firmware |
edamame22 | 0:e0794665caf1 | 36 | * 5. moved class private variables into member functions |
edamame22 | 0:e0794665caf1 | 37 | * 6. other small improvements |
edamame22 | 0:e0794665caf1 | 38 | * |
edamame22 | 0:e0794665caf1 | 39 | */ |
edamame22 | 0:e0794665caf1 | 40 | #include "mbed.h" |
edamame22 | 0:e0794665caf1 | 41 | #include "multigas_sensor.h" |
edamame22 | 0:e0794665caf1 | 42 | |
edamame22 | 0:e0794665caf1 | 43 | MiCS6814_GasSensor::MiCS6814_GasSensor(PinName sda, PinName scl, char slave_adr) |
edamame22 | 0:e0794665caf1 | 44 | : |
edamame22 | 0:e0794665caf1 | 45 | _i2c_p(new I2C(sda, scl)), |
edamame22 | 0:e0794665caf1 | 46 | _i2c(*_i2c_p), |
edamame22 | 0:e0794665caf1 | 47 | _address(slave_adr) |
edamame22 | 0:e0794665caf1 | 48 | { |
edamame22 | 0:e0794665caf1 | 49 | initialize(); |
edamame22 | 0:e0794665caf1 | 50 | } |
edamame22 | 0:e0794665caf1 | 51 | |
edamame22 | 0:e0794665caf1 | 52 | MiCS6814_GasSensor::MiCS6814_GasSensor(I2C &i2c_obj, char slave_adr) |
edamame22 | 0:e0794665caf1 | 53 | : |
edamame22 | 0:e0794665caf1 | 54 | _i2c_p(NULL), |
edamame22 | 0:e0794665caf1 | 55 | _i2c(i2c_obj), |
edamame22 | 0:e0794665caf1 | 56 | _address(slave_adr) |
edamame22 | 0:e0794665caf1 | 57 | { |
edamame22 | 0:e0794665caf1 | 58 | initialize(); |
edamame22 | 0:e0794665caf1 | 59 | } |
edamame22 | 0:e0794665caf1 | 60 | |
edamame22 | 0:e0794665caf1 | 61 | MiCS6814_GasSensor::~MiCS6814_GasSensor() |
edamame22 | 0:e0794665caf1 | 62 | { |
edamame22 | 0:e0794665caf1 | 63 | HeaterPower(false); // turn off the heater |
edamame22 | 0:e0794665caf1 | 64 | if (NULL != _i2c_p) |
edamame22 | 0:e0794665caf1 | 65 | { |
edamame22 | 0:e0794665caf1 | 66 | delete _i2c_p; |
edamame22 | 0:e0794665caf1 | 67 | } |
edamame22 | 0:e0794665caf1 | 68 | } |
edamame22 | 0:e0794665caf1 | 69 | |
edamame22 | 0:e0794665caf1 | 70 | |
edamame22 | 0:e0794665caf1 | 71 | READ_ERROR_TYPE MiCS6814_GasSensor::read_Multibytes(unsigned char addr_reg, unsigned char __dta, unsigned char write_len, unsigned char read_len, uint16_t * ret_val) |
edamame22 | 0:e0794665caf1 | 72 | { |
edamame22 | 0:e0794665caf1 | 73 | char cmd[2], val[4]; // write buf, read buf |
edamame22 | 0:e0794665caf1 | 74 | uint8_t checksum=0; |
edamame22 | 0:e0794665caf1 | 75 | |
edamame22 | 0:e0794665caf1 | 76 | if (ret_val==NULL) { |
edamame22 | 0:e0794665caf1 | 77 | return NULL_RETURN_BUFFER_PTR; // ret_val is a NULL pointer |
edamame22 | 0:e0794665caf1 | 78 | } |
edamame22 | 0:e0794665caf1 | 79 | if(write_len>2 || write_len<1) { |
edamame22 | 0:e0794665caf1 | 80 | return WRITE_LENGTH_ERROR; // write_len is wrong |
edamame22 | 0:e0794665caf1 | 81 | } |
edamame22 | 0:e0794665caf1 | 82 | if (read_len!=2 && read_len!=4) { |
edamame22 | 0:e0794665caf1 | 83 | return READ_LENGTH_ERROR; // read_len is wrong |
edamame22 | 0:e0794665caf1 | 84 | } |
edamame22 | 0:e0794665caf1 | 85 | *ret_val=0; // clear return buf |
edamame22 | 0:e0794665caf1 | 86 | |
edamame22 | 0:e0794665caf1 | 87 | cmd[0] = addr_reg; |
edamame22 | 0:e0794665caf1 | 88 | if (write_len==2) { |
edamame22 | 0:e0794665caf1 | 89 | cmd[1] = __dta; |
edamame22 | 0:e0794665caf1 | 90 | } |
edamame22 | 0:e0794665caf1 | 91 | _i2c.write(_address, cmd, write_len); |
edamame22 | 0:e0794665caf1 | 92 | |
edamame22 | 0:e0794665caf1 | 93 | _i2c.read(_address, val, read_len); |
edamame22 | 0:e0794665caf1 | 94 | |
edamame22 | 0:e0794665caf1 | 95 | if (read_len==2) { |
edamame22 | 0:e0794665caf1 | 96 | *ret_val = (uint16_t) (val[0]<<8 | val[1]) ; // set return value to caller |
edamame22 | 0:e0794665caf1 | 97 | #ifdef _DEBUG |
edamame22 | 0:e0794665caf1 | 98 | if(*ret_val==0) DEBUG_PRINT("read_Multibytes, *ret_val=0, addr_reg: 0x%x, write_len: %x, read_len: %x\r\n", addr_reg, write_len, read_len ); |
edamame22 | 0:e0794665caf1 | 99 | #endif |
edamame22 | 0:e0794665caf1 | 100 | }else if (read_len==4) { |
edamame22 | 0:e0794665caf1 | 101 | checksum = (uint8_t)(val[0] + val[1] + val[2]); |
edamame22 | 0:e0794665caf1 | 102 | if(checksum != val[3]){ |
edamame22 | 0:e0794665caf1 | 103 | DEBUG_PRINT("checksum failed, val[4]: 0x%x, 0x%x, 0x%x, 0x%x, checksum: 0x%x\r\n", val[0], val[1], val[2], val[3], checksum ); |
edamame22 | 0:e0794665caf1 | 104 | DEBUG_PRINT("checksum failed i2c.read, addr_reg: 0x%x, write_len: %x, read_len: %x\r\n", addr_reg, write_len, read_len ); |
edamame22 | 0:e0794665caf1 | 105 | return CHECKSUM_ERROR; //checksum is wrong |
edamame22 | 0:e0794665caf1 | 106 | } |
edamame22 | 0:e0794665caf1 | 107 | *ret_val = (uint16_t) ((val[1] << 8) + val[2]); |
edamame22 | 0:e0794665caf1 | 108 | } |
edamame22 | 0:e0794665caf1 | 109 | return READ_OK; |
edamame22 | 0:e0794665caf1 | 110 | } |
edamame22 | 0:e0794665caf1 | 111 | |
edamame22 | 0:e0794665caf1 | 112 | void MiCS6814_GasSensor::CheckFirmwareVersion() |
edamame22 | 0:e0794665caf1 | 113 | { |
edamame22 | 0:e0794665caf1 | 114 | uint16_t readBuf=0; |
edamame22 | 0:e0794665caf1 | 115 | unsigned char ret_val = read_Multibytes(CMD_READ_EEPROM, ADDR_IS_SET, 2, 2, &readBuf); // read firmware version |
edamame22 | 0:e0794665caf1 | 116 | // only support version = 2 |
edamame22 | 0:e0794665caf1 | 117 | MBED_ASSERT(ret_val == READ_OK && readBuf == 1126); |
edamame22 | 0:e0794665caf1 | 118 | } |
edamame22 | 0:e0794665caf1 | 119 | |
edamame22 | 0:e0794665caf1 | 120 | |
edamame22 | 0:e0794665caf1 | 121 | void MiCS6814_GasSensor::HeaterPower(bool Switch_On) |
edamame22 | 0:e0794665caf1 | 122 | { |
edamame22 | 0:e0794665caf1 | 123 | const unsigned char v2tmp[2]={0, 1}; // On, Off command for version 2 |
edamame22 | 0:e0794665caf1 | 124 | char tmp[4]; |
edamame22 | 0:e0794665caf1 | 125 | DEBUG_PRINT("Sensor heater Power :%s\r\n", Switch_On? "On":"Off"); |
edamame22 | 0:e0794665caf1 | 126 | tmp[0] = 11; |
edamame22 | 0:e0794665caf1 | 127 | tmp[1] = v2tmp[Switch_On]; |
edamame22 | 0:e0794665caf1 | 128 | _i2c.write(_address, tmp, 2); |
edamame22 | 0:e0794665caf1 | 129 | } |
edamame22 | 0:e0794665caf1 | 130 | |
edamame22 | 0:e0794665caf1 | 131 | uint16_t MiCS6814_GasSensor::readR0_A0(unsigned char _indix) |
edamame22 | 0:e0794665caf1 | 132 | { |
edamame22 | 0:e0794665caf1 | 133 | uint16_t readBuf=0; |
edamame22 | 0:e0794665caf1 | 134 | const unsigned char A0_table[3]={ADDR_USER_ADC_HN3, ADDR_USER_ADC_CO, ADDR_USER_ADC_NO2}; |
edamame22 | 0:e0794665caf1 | 135 | unsigned char ret_val; |
edamame22 | 0:e0794665caf1 | 136 | // version 2 : read A0_[_indix] |
edamame22 | 0:e0794665caf1 | 137 | ret_val= read_Multibytes(CMD_READ_EEPROM, A0_table[_indix], 2, 2, &readBuf); |
edamame22 | 0:e0794665caf1 | 138 | DEBUG_PRINT("A0_[%d]: %d, ", _indix, readBuf); |
edamame22 | 0:e0794665caf1 | 139 | if (ret_val == READ_OK) { |
edamame22 | 0:e0794665caf1 | 140 | return readBuf; |
edamame22 | 0:e0794665caf1 | 141 | } |
edamame22 | 0:e0794665caf1 | 142 | // read failed, Rs[_indix] |
edamame22 | 0:e0794665caf1 | 143 | DEBUG_PRINT("A0_[%d] read error: %d\r\n", _indix, ret_val); |
edamame22 | 0:e0794665caf1 | 144 | return 0; |
edamame22 | 0:e0794665caf1 | 145 | } |
edamame22 | 0:e0794665caf1 | 146 | |
edamame22 | 0:e0794665caf1 | 147 | |
edamame22 | 0:e0794665caf1 | 148 | uint16_t MiCS6814_GasSensor::readRs_An(unsigned char _indix) |
edamame22 | 0:e0794665caf1 | 149 | { |
edamame22 | 0:e0794665caf1 | 150 | uint16_t readBuf=0; |
edamame22 | 0:e0794665caf1 | 151 | const unsigned char An_table[3]={CH_VALUE_NH3, CH_VALUE_CO, CH_VALUE_NO2}; |
edamame22 | 0:e0794665caf1 | 152 | unsigned char ret_val; |
edamame22 | 0:e0794665caf1 | 153 | // version 2 : read An_[_indix] |
edamame22 | 0:e0794665caf1 | 154 | ret_val= read_Multibytes(An_table[_indix], 0, 1, 2, &readBuf); |
edamame22 | 0:e0794665caf1 | 155 | DEBUG_PRINT("An_[%d]: %d, ", _indix, readBuf); |
edamame22 | 0:e0794665caf1 | 156 | if (ret_val == READ_OK) { |
edamame22 | 0:e0794665caf1 | 157 | return readBuf; |
edamame22 | 0:e0794665caf1 | 158 | } |
edamame22 | 0:e0794665caf1 | 159 | // read failed, Rs[_indix] |
edamame22 | 0:e0794665caf1 | 160 | DEBUG_PRINT("An_[%d] read error: %d\r\n", _indix, ret_val); |
edamame22 | 0:e0794665caf1 | 161 | return 0; |
edamame22 | 0:e0794665caf1 | 162 | } |
edamame22 | 0:e0794665caf1 | 163 | |
edamame22 | 0:e0794665caf1 | 164 | |
edamame22 | 0:e0794665caf1 | 165 | float MiCS6814_GasSensor::calcGas(const GAS_TYPE gas_type) |
edamame22 | 0:e0794665caf1 | 166 | { |
edamame22 | 0:e0794665caf1 | 167 | int A0_[3], An_[3]; |
edamame22 | 0:e0794665caf1 | 168 | const unsigned char GasType_2index[8] ={/* NH3 */ 0,/* CO */ 1,/* NO2 */ 2,/*C3H8 */ 0,/* C4H10 */ 0,/* CH4 */ 1,/* H2 */ 1,/* C2H5OH */ 1}; |
edamame22 | 0:e0794665caf1 | 169 | unsigned char _index = GasType_2index[gas_type]; |
edamame22 | 0:e0794665caf1 | 170 | float Ratio[3]; //will be calculated. ration 0,1,2 |
edamame22 | 0:e0794665caf1 | 171 | |
edamame22 | 0:e0794665caf1 | 172 | // prepare necessary Ratio[x] according to gas_type |
edamame22 | 0:e0794665caf1 | 173 | An_[_index] = readRs_An(_index); // read An_[x] |
edamame22 | 0:e0794665caf1 | 174 | A0_[_index] = readR0_A0(_index); // read R0[x] |
edamame22 | 0:e0794665caf1 | 175 | Ratio[_index] = (float)An_[_index]/(float)A0_[_index]*(1023.0-A0_[_index])/(1023.0-An_[_index]); |
edamame22 | 0:e0794665caf1 | 176 | DEBUG_PRINT("Ratio[%d]: %.3f, ", _index, Ratio[_index]); |
edamame22 | 0:e0794665caf1 | 177 | |
edamame22 | 0:e0794665caf1 | 178 | float calcu_val = 0.0f; |
edamame22 | 0:e0794665caf1 | 179 | // calculate concentration value of specified gas_type |
edamame22 | 0:e0794665caf1 | 180 | switch(gas_type) |
edamame22 | 0:e0794665caf1 | 181 | { |
edamame22 | 0:e0794665caf1 | 182 | case CO: |
edamame22 | 0:e0794665caf1 | 183 | { |
edamame22 | 0:e0794665caf1 | 184 | calcu_val = pow(Ratio[1], -1.179f)*4.385f; |
edamame22 | 0:e0794665caf1 | 185 | break; |
edamame22 | 0:e0794665caf1 | 186 | } |
edamame22 | 0:e0794665caf1 | 187 | case NO2: |
edamame22 | 0:e0794665caf1 | 188 | { |
edamame22 | 0:e0794665caf1 | 189 | calcu_val = pow(Ratio[2], 1.007f)/6.855f; |
edamame22 | 0:e0794665caf1 | 190 | break; |
edamame22 | 0:e0794665caf1 | 191 | } |
edamame22 | 0:e0794665caf1 | 192 | case NH3: |
edamame22 | 0:e0794665caf1 | 193 | { |
edamame22 | 0:e0794665caf1 | 194 | calcu_val = pow(Ratio[0], -1.67f)/1.47f; |
edamame22 | 0:e0794665caf1 | 195 | break; |
edamame22 | 0:e0794665caf1 | 196 | } |
edamame22 | 0:e0794665caf1 | 197 | case C3H8: |
edamame22 | 0:e0794665caf1 | 198 | { |
edamame22 | 0:e0794665caf1 | 199 | calcu_val = pow(Ratio[0], -2.518f)*570.164f; |
edamame22 | 0:e0794665caf1 | 200 | break; |
edamame22 | 0:e0794665caf1 | 201 | } |
edamame22 | 0:e0794665caf1 | 202 | case C4H10: |
edamame22 | 0:e0794665caf1 | 203 | { |
edamame22 | 0:e0794665caf1 | 204 | calcu_val = pow(Ratio[0], -2.138f)*398.107f; |
edamame22 | 0:e0794665caf1 | 205 | break; |
edamame22 | 0:e0794665caf1 | 206 | } |
edamame22 | 0:e0794665caf1 | 207 | case CH4: |
edamame22 | 0:e0794665caf1 | 208 | { |
edamame22 | 0:e0794665caf1 | 209 | calcu_val = pow(Ratio[1], -4.363f)*630.957f; |
edamame22 | 0:e0794665caf1 | 210 | break; |
edamame22 | 0:e0794665caf1 | 211 | } |
edamame22 | 0:e0794665caf1 | 212 | case H2: |
edamame22 | 0:e0794665caf1 | 213 | { |
edamame22 | 0:e0794665caf1 | 214 | calcu_val = pow(Ratio[1], -1.8f)*0.73f; |
edamame22 | 0:e0794665caf1 | 215 | break; |
edamame22 | 0:e0794665caf1 | 216 | } |
edamame22 | 0:e0794665caf1 | 217 | case C2H5OH: |
edamame22 | 0:e0794665caf1 | 218 | { |
edamame22 | 0:e0794665caf1 | 219 | calcu_val = pow(Ratio[1], -1.552f)*1.622f; |
edamame22 | 0:e0794665caf1 | 220 | break; |
edamame22 | 0:e0794665caf1 | 221 | } |
edamame22 | 0:e0794665caf1 | 222 | default: |
edamame22 | 0:e0794665caf1 | 223 | break; |
edamame22 | 0:e0794665caf1 | 224 | } |
edamame22 | 0:e0794665caf1 | 225 | |
edamame22 | 0:e0794665caf1 | 226 | return calcu_val; |
edamame22 | 0:e0794665caf1 | 227 | } |
edamame22 | 0:e0794665caf1 | 228 | |
edamame22 | 0:e0794665caf1 | 229 | |
edamame22 | 0:e0794665caf1 | 230 | |
edamame22 | 0:e0794665caf1 | 231 | void MiCS6814_GasSensor::initialize() |
edamame22 | 0:e0794665caf1 | 232 | { |
edamame22 | 0:e0794665caf1 | 233 | |
edamame22 | 0:e0794665caf1 | 234 | CheckFirmwareVersion(); |
edamame22 | 0:e0794665caf1 | 235 | HeaterPower(true); // turn on the heater. |
edamame22 | 0:e0794665caf1 | 236 | } |