A component library for MiCS-6814 Multichannel Gas Sensor (seeed)
Dependents: MiCS6814_GasSensor_Hello grove_multichannel_GasSensor
MiCS6814_GasSensor.cpp@4:a15eee9bb0e6, 2017-05-25 (annotated)
- Committer:
- edamame22
- Date:
- Thu May 25 03:16:47 2017 +0000
- Revision:
- 4:a15eee9bb0e6
- Parent:
- 3:93b7f86b72e1
added pin name definition for I2C in header file.
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 | 1:5caeba593de4 | 3 | * @file MiCS6814_GasSensor.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 | 1:5caeba593de4 | 29 | |
edamame22 | 0:e0794665caf1 | 30 | #include "mbed.h" |
edamame22 | 1:5caeba593de4 | 31 | #include "MiCS6814_GasSensor.h" |
edamame22 | 0:e0794665caf1 | 32 | |
edamame22 | 0:e0794665caf1 | 33 | MiCS6814_GasSensor::MiCS6814_GasSensor(PinName sda, PinName scl, char slave_adr) |
edamame22 | 0:e0794665caf1 | 34 | : |
edamame22 | 0:e0794665caf1 | 35 | _i2c_p(new I2C(sda, scl)), |
edamame22 | 0:e0794665caf1 | 36 | _i2c(*_i2c_p), |
edamame22 | 0:e0794665caf1 | 37 | _address(slave_adr) |
edamame22 | 0:e0794665caf1 | 38 | { |
edamame22 | 0:e0794665caf1 | 39 | initialize(); |
edamame22 | 0:e0794665caf1 | 40 | } |
edamame22 | 0:e0794665caf1 | 41 | |
edamame22 | 0:e0794665caf1 | 42 | MiCS6814_GasSensor::MiCS6814_GasSensor(I2C &i2c_obj, char slave_adr) |
edamame22 | 0:e0794665caf1 | 43 | : |
edamame22 | 0:e0794665caf1 | 44 | _i2c_p(NULL), |
edamame22 | 0:e0794665caf1 | 45 | _i2c(i2c_obj), |
edamame22 | 0:e0794665caf1 | 46 | _address(slave_adr) |
edamame22 | 0:e0794665caf1 | 47 | { |
edamame22 | 0:e0794665caf1 | 48 | initialize(); |
edamame22 | 0:e0794665caf1 | 49 | } |
edamame22 | 0:e0794665caf1 | 50 | |
edamame22 | 0:e0794665caf1 | 51 | MiCS6814_GasSensor::~MiCS6814_GasSensor() |
edamame22 | 0:e0794665caf1 | 52 | { |
edamame22 | 1:5caeba593de4 | 53 | HeaterPower(HEATER_OFF); // turn off the heater |
edamame22 | 1:5caeba593de4 | 54 | if (NULL != _i2c_p) { |
edamame22 | 0:e0794665caf1 | 55 | delete _i2c_p; |
edamame22 | 0:e0794665caf1 | 56 | } |
edamame22 | 0:e0794665caf1 | 57 | } |
edamame22 | 0:e0794665caf1 | 58 | |
edamame22 | 0:e0794665caf1 | 59 | 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 | 60 | { |
edamame22 | 0:e0794665caf1 | 61 | char cmd[2], val[4]; // write buf, read buf |
edamame22 | 0:e0794665caf1 | 62 | uint8_t checksum=0; |
edamame22 | 0:e0794665caf1 | 63 | |
edamame22 | 1:5caeba593de4 | 64 | if (write_len>2 || write_len<1) { |
edamame22 | 0:e0794665caf1 | 65 | return WRITE_LENGTH_ERROR; // write_len is wrong |
edamame22 | 0:e0794665caf1 | 66 | } |
edamame22 | 0:e0794665caf1 | 67 | if (read_len!=2 && read_len!=4) { |
edamame22 | 0:e0794665caf1 | 68 | return READ_LENGTH_ERROR; // read_len is wrong |
edamame22 | 0:e0794665caf1 | 69 | } |
edamame22 | 0:e0794665caf1 | 70 | *ret_val=0; // clear return buf |
edamame22 | 0:e0794665caf1 | 71 | |
edamame22 | 0:e0794665caf1 | 72 | cmd[0] = addr_reg; |
edamame22 | 0:e0794665caf1 | 73 | if (write_len==2) { |
edamame22 | 0:e0794665caf1 | 74 | cmd[1] = __dta; |
edamame22 | 0:e0794665caf1 | 75 | } |
edamame22 | 0:e0794665caf1 | 76 | _i2c.write(_address, cmd, write_len); |
MACRUM | 3:93b7f86b72e1 | 77 | wait(0.1f); |
edamame22 | 0:e0794665caf1 | 78 | _i2c.read(_address, val, read_len); |
edamame22 | 0:e0794665caf1 | 79 | if (read_len==2) { |
edamame22 | 0:e0794665caf1 | 80 | *ret_val = (uint16_t) (val[0]<<8 | val[1]) ; // set return value to caller |
edamame22 | 1:5caeba593de4 | 81 | if (*ret_val==0) { |
edamame22 | 1:5caeba593de4 | 82 | 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 | 1:5caeba593de4 | 83 | } |
edamame22 | 1:5caeba593de4 | 84 | } else if (read_len==4) { |
edamame22 | 0:e0794665caf1 | 85 | checksum = (uint8_t)(val[0] + val[1] + val[2]); |
edamame22 | 1:5caeba593de4 | 86 | if (checksum != val[3]) { |
edamame22 | 0:e0794665caf1 | 87 | 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 | 88 | 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 | 89 | return CHECKSUM_ERROR; //checksum is wrong |
edamame22 | 0:e0794665caf1 | 90 | } |
edamame22 | 0:e0794665caf1 | 91 | *ret_val = (uint16_t) ((val[1] << 8) + val[2]); |
edamame22 | 0:e0794665caf1 | 92 | } |
edamame22 | 0:e0794665caf1 | 93 | return READ_OK; |
edamame22 | 0:e0794665caf1 | 94 | } |
edamame22 | 0:e0794665caf1 | 95 | |
edamame22 | 0:e0794665caf1 | 96 | void MiCS6814_GasSensor::CheckFirmwareVersion() |
edamame22 | 0:e0794665caf1 | 97 | { |
edamame22 | 0:e0794665caf1 | 98 | uint16_t readBuf=0; |
edamame22 | 0:e0794665caf1 | 99 | unsigned char ret_val = read_Multibytes(CMD_READ_EEPROM, ADDR_IS_SET, 2, 2, &readBuf); // read firmware version |
edamame22 | 0:e0794665caf1 | 100 | // only support version = 2 |
edamame22 | 0:e0794665caf1 | 101 | MBED_ASSERT(ret_val == READ_OK && readBuf == 1126); |
edamame22 | 0:e0794665caf1 | 102 | } |
edamame22 | 0:e0794665caf1 | 103 | |
edamame22 | 1:5caeba593de4 | 104 | void MiCS6814_GasSensor::HeaterPower(const unsigned char Switch_On) |
edamame22 | 0:e0794665caf1 | 105 | { |
edamame22 | 1:5caeba593de4 | 106 | char tmp[2]; |
edamame22 | 1:5caeba593de4 | 107 | DEBUG_PRINT("Sensor heater Power :%s\r\n", Switch_On==1? "On":"Off"); |
edamame22 | 1:5caeba593de4 | 108 | tmp[0] = CMD_CONTROL_PWR; |
edamame22 | 1:5caeba593de4 | 109 | tmp[1] = Switch_On; |
edamame22 | 0:e0794665caf1 | 110 | _i2c.write(_address, tmp, 2); |
MACRUM | 3:93b7f86b72e1 | 111 | wait(0.1f); |
edamame22 | 0:e0794665caf1 | 112 | } |
edamame22 | 0:e0794665caf1 | 113 | |
MACRUM | 3:93b7f86b72e1 | 114 | uint16_t MiCS6814_GasSensor::readR0_A0(unsigned char index) |
edamame22 | 0:e0794665caf1 | 115 | { |
edamame22 | 1:5caeba593de4 | 116 | uint16_t readBuf= 0; |
edamame22 | 1:5caeba593de4 | 117 | const unsigned char A0_table[3]= {ADDR_USER_ADC_HN3, ADDR_USER_ADC_CO, ADDR_USER_ADC_NO2}; |
edamame22 | 0:e0794665caf1 | 118 | unsigned char ret_val; |
edamame22 | 1:5caeba593de4 | 119 | |
MACRUM | 3:93b7f86b72e1 | 120 | ret_val= read_Multibytes(CMD_READ_EEPROM, A0_table[index], 2, 2, &readBuf); |
MACRUM | 3:93b7f86b72e1 | 121 | DEBUG_PRINT("A0_[%d]: %d, ", index, readBuf); |
edamame22 | 0:e0794665caf1 | 122 | if (ret_val == READ_OK) { |
edamame22 | 0:e0794665caf1 | 123 | return readBuf; |
edamame22 | 0:e0794665caf1 | 124 | } |
MACRUM | 3:93b7f86b72e1 | 125 | // read failed, A0_[index] |
MACRUM | 3:93b7f86b72e1 | 126 | DEBUG_PRINT("A0_[%d] read error: %d\r\n", index, ret_val); |
edamame22 | 0:e0794665caf1 | 127 | return 0; |
edamame22 | 0:e0794665caf1 | 128 | } |
edamame22 | 0:e0794665caf1 | 129 | |
MACRUM | 3:93b7f86b72e1 | 130 | uint16_t MiCS6814_GasSensor::readRs_An(unsigned char index) |
edamame22 | 0:e0794665caf1 | 131 | { |
edamame22 | 1:5caeba593de4 | 132 | uint16_t readBuf= 0; |
edamame22 | 1:5caeba593de4 | 133 | const unsigned char An_table[3]= {CH_VALUE_NH3, CH_VALUE_CO, CH_VALUE_NO2}; |
edamame22 | 0:e0794665caf1 | 134 | unsigned char ret_val; |
edamame22 | 1:5caeba593de4 | 135 | |
MACRUM | 3:93b7f86b72e1 | 136 | ret_val= read_Multibytes(An_table[index], 0, 1, 2, &readBuf); |
MACRUM | 3:93b7f86b72e1 | 137 | DEBUG_PRINT("An_[%d]: %d, ", index, readBuf); |
edamame22 | 0:e0794665caf1 | 138 | if (ret_val == READ_OK) { |
edamame22 | 0:e0794665caf1 | 139 | return readBuf; |
edamame22 | 0:e0794665caf1 | 140 | } |
MACRUM | 3:93b7f86b72e1 | 141 | // read failed, An_[index] |
MACRUM | 3:93b7f86b72e1 | 142 | DEBUG_PRINT("An_[%d] read error: %d\r\n", index, ret_val); |
edamame22 | 0:e0794665caf1 | 143 | return 0; |
edamame22 | 0:e0794665caf1 | 144 | } |
edamame22 | 0:e0794665caf1 | 145 | |
MACRUM | 3:93b7f86b72e1 | 146 | float MiCS6814_GasSensor::getGas(const GAS_TYPE gas_type) |
edamame22 | 0:e0794665caf1 | 147 | { |
edamame22 | 0:e0794665caf1 | 148 | int A0_[3], An_[3]; |
edamame22 | 1:5caeba593de4 | 149 | const unsigned char GasType_2index[8] = {0, 1, 2, 0, 0, 1, 1, 1}; |
MACRUM | 3:93b7f86b72e1 | 150 | unsigned char index = GasType_2index[gas_type]; |
edamame22 | 1:5caeba593de4 | 151 | float Ratio[3]; //will be calculated. Ratio 0,1,2 |
edamame22 | 0:e0794665caf1 | 152 | |
edamame22 | 0:e0794665caf1 | 153 | // prepare necessary Ratio[x] according to gas_type |
MACRUM | 3:93b7f86b72e1 | 154 | An_[index] = readRs_An(index); // read An_[x] |
MACRUM | 3:93b7f86b72e1 | 155 | A0_[index] = readR0_A0(index); // read R0[x] |
MACRUM | 3:93b7f86b72e1 | 156 | Ratio[index] = (float)An_[index]/(float)A0_[index]*(1023.0-A0_[index])/(1023.0-An_[index]); |
MACRUM | 3:93b7f86b72e1 | 157 | DEBUG_PRINT("Ratio[%d]: %.3f, ", index, Ratio[index]); |
edamame22 | 0:e0794665caf1 | 158 | |
edamame22 | 0:e0794665caf1 | 159 | float calcu_val = 0.0f; |
edamame22 | 0:e0794665caf1 | 160 | // calculate concentration value of specified gas_type |
edamame22 | 1:5caeba593de4 | 161 | switch(gas_type) { |
MACRUM | 3:93b7f86b72e1 | 162 | case CO: |
edamame22 | 0:e0794665caf1 | 163 | calcu_val = pow(Ratio[1], -1.179f)*4.385f; |
edamame22 | 0:e0794665caf1 | 164 | break; |
MACRUM | 3:93b7f86b72e1 | 165 | case NO2: |
edamame22 | 0:e0794665caf1 | 166 | calcu_val = pow(Ratio[2], 1.007f)/6.855f; |
edamame22 | 0:e0794665caf1 | 167 | break; |
MACRUM | 3:93b7f86b72e1 | 168 | case NH3: |
edamame22 | 0:e0794665caf1 | 169 | calcu_val = pow(Ratio[0], -1.67f)/1.47f; |
edamame22 | 0:e0794665caf1 | 170 | break; |
MACRUM | 3:93b7f86b72e1 | 171 | case C3H8: |
edamame22 | 0:e0794665caf1 | 172 | calcu_val = pow(Ratio[0], -2.518f)*570.164f; |
edamame22 | 0:e0794665caf1 | 173 | break; |
MACRUM | 3:93b7f86b72e1 | 174 | case C4H10: |
edamame22 | 0:e0794665caf1 | 175 | calcu_val = pow(Ratio[0], -2.138f)*398.107f; |
edamame22 | 0:e0794665caf1 | 176 | break; |
MACRUM | 3:93b7f86b72e1 | 177 | case CH4: |
edamame22 | 0:e0794665caf1 | 178 | calcu_val = pow(Ratio[1], -4.363f)*630.957f; |
edamame22 | 0:e0794665caf1 | 179 | break; |
MACRUM | 3:93b7f86b72e1 | 180 | case H2: |
edamame22 | 0:e0794665caf1 | 181 | calcu_val = pow(Ratio[1], -1.8f)*0.73f; |
edamame22 | 0:e0794665caf1 | 182 | break; |
MACRUM | 3:93b7f86b72e1 | 183 | case C2H5OH: |
edamame22 | 0:e0794665caf1 | 184 | calcu_val = pow(Ratio[1], -1.552f)*1.622f; |
edamame22 | 0:e0794665caf1 | 185 | break; |
edamame22 | 0:e0794665caf1 | 186 | default: |
edamame22 | 0:e0794665caf1 | 187 | break; |
edamame22 | 0:e0794665caf1 | 188 | } |
edamame22 | 0:e0794665caf1 | 189 | return calcu_val; |
edamame22 | 0:e0794665caf1 | 190 | } |
edamame22 | 0:e0794665caf1 | 191 | |
edamame22 | 0:e0794665caf1 | 192 | void MiCS6814_GasSensor::initialize() |
edamame22 | 0:e0794665caf1 | 193 | { |
edamame22 | 0:e0794665caf1 | 194 | CheckFirmwareVersion(); |
edamame22 | 1:5caeba593de4 | 195 | HeaterPower(HEATER_ON); // turn on the heater. |
edamame22 | 0:e0794665caf1 | 196 | } |