Revision 3:93b7f86b72e1, committed 2017-05-24

Comitter:

MACRUM

Date:

Wed May 24 10:03:01 2017 +0000

Parent:

2:8d61377f2e2a

Child:

4:a15eee9bb0e6

Commit message:

Update docs, add wait between i2c::write and read, correct example code.

Changed in this revision

--- a/MiCS6814_GasSensor.cpp	Wed May 24 13:38:46 2017 +0900
+++ b/MiCS6814_GasSensor.cpp	Wed May 24 10:03:01 2017 +0000
@@ -61,9 +61,6 @@
     char cmd[2], val[4];     // write buf, read buf
     uint8_t checksum=0;
 
-    if (ret_val==NULL) {
-        return NULL_RETURN_BUFFER_PTR;     // ret_val is a NULL pointer
-    }
     if (write_len>2 || write_len<1) {
         return WRITE_LENGTH_ERROR;         // write_len is wrong
     }
@@ -77,6 +74,7 @@
         cmd[1] = __dta;
     }
     _i2c.write(_address, cmd, write_len);
+    wait(0.1f);
     _i2c.read(_address, val, read_len);
     if (read_len==2) {
         *ret_val = (uint16_t) (val[0]<<8 | val[1]) ;   // set return value to caller
@@ -110,88 +108,81 @@
     tmp[0] = CMD_CONTROL_PWR;
     tmp[1] = Switch_On;
     _i2c.write(_address, tmp, 2);
+    wait(0.1f);
 }
 
-uint16_t MiCS6814_GasSensor::readR0_A0(unsigned char _indix)
+uint16_t MiCS6814_GasSensor::readR0_A0(unsigned char index)
 {
     uint16_t readBuf= 0;
     const unsigned char A0_table[3]= {ADDR_USER_ADC_HN3, ADDR_USER_ADC_CO, ADDR_USER_ADC_NO2};
     unsigned char ret_val;
 
-    ret_val= read_Multibytes(CMD_READ_EEPROM, A0_table[_indix], 2, 2, &readBuf);
-    DEBUG_PRINT("A0_[%d]: %d,    ", _indix, readBuf);
+    ret_val= read_Multibytes(CMD_READ_EEPROM, A0_table[index], 2, 2, &readBuf);
+    DEBUG_PRINT("A0_[%d]: %d,    ", index, readBuf);
     if (ret_val == READ_OK) {
         return readBuf;
     }
-    // read failed, A0_[_indix]
-    DEBUG_PRINT("A0_[%d] read error: %d\r\n", _indix, ret_val);
+    // read failed, A0_[index]
+    DEBUG_PRINT("A0_[%d] read error: %d\r\n", index, ret_val);
     return 0;
 }
 
-uint16_t MiCS6814_GasSensor::readRs_An(unsigned char _indix)
+uint16_t MiCS6814_GasSensor::readRs_An(unsigned char index)
 {
     uint16_t readBuf= 0;
     const unsigned char An_table[3]= {CH_VALUE_NH3, CH_VALUE_CO, CH_VALUE_NO2};
     unsigned char ret_val;
 
-    ret_val= read_Multibytes(An_table[_indix], 0, 1, 2, &readBuf);
-    DEBUG_PRINT("An_[%d]: %d,    ", _indix, readBuf);
+    ret_val= read_Multibytes(An_table[index], 0, 1, 2, &readBuf);
+    DEBUG_PRINT("An_[%d]: %d,    ", index, readBuf);
     if (ret_val == READ_OK) {
         return readBuf;
     }
-    // read failed, An_[_indix]
-    DEBUG_PRINT("An_[%d] read error: %d\r\n", _indix, ret_val);
+    // read failed, An_[index]
+    DEBUG_PRINT("An_[%d] read error: %d\r\n", index, ret_val);
     return 0;
 }
 
-float MiCS6814_GasSensor::calcGas(const GAS_TYPE gas_type)
+float MiCS6814_GasSensor::getGas(const GAS_TYPE gas_type)
 {
     int A0_[3], An_[3];
     const unsigned char GasType_2index[8] = {0, 1, 2, 0, 0, 1, 1, 1};
-    unsigned char _index = GasType_2index[gas_type];
+    unsigned char index = GasType_2index[gas_type];
     float Ratio[3];        //will be calculated. Ratio 0,1,2
 
     // prepare necessary Ratio[x] according to gas_type
-    An_[_index] = readRs_An(_index);      // read An_[x]
-    A0_[_index] = readR0_A0(_index);      // read R0[x]
-    Ratio[_index] = (float)An_[_index]/(float)A0_[_index]*(1023.0-A0_[_index])/(1023.0-An_[_index]);
-    DEBUG_PRINT("Ratio[%d]: %.3f,   ", _index, Ratio[_index]);
+    An_[index] = readRs_An(index);      // read An_[x]
+    A0_[index] = readR0_A0(index);      // read R0[x]
+    Ratio[index] = (float)An_[index]/(float)A0_[index]*(1023.0-A0_[index])/(1023.0-An_[index]);
+    DEBUG_PRINT("Ratio[%d]: %.3f,   ", index, Ratio[index]);
 
     float calcu_val = 0.0f;
     // calculate concentration value of specified gas_type
     switch(gas_type) {
-        case CO: {
+        case CO:
             calcu_val = pow(Ratio[1], -1.179f)*4.385f;
             break;
-        }
-        case NO2: {
+        case NO2:
             calcu_val = pow(Ratio[2], 1.007f)/6.855f;
             break;
-        }
-        case NH3: {
+        case NH3:
             calcu_val = pow(Ratio[0], -1.67f)/1.47f;
             break;
-        }
-        case C3H8: {
+        case C3H8:
             calcu_val = pow(Ratio[0], -2.518f)*570.164f;
             break;
-        }
-        case C4H10: {
+        case C4H10:
             calcu_val = pow(Ratio[0], -2.138f)*398.107f;
             break;
-        }
-        case CH4: {
+        case CH4:
             calcu_val = pow(Ratio[1], -4.363f)*630.957f;
             break;
-        }
-        case H2: {
+        case H2:
             calcu_val = pow(Ratio[1], -1.8f)*0.73f;
             break;
-        }
-        case C2H5OH: {
+        case C2H5OH:
             calcu_val = pow(Ratio[1], -1.552f)*1.622f;
             break;
-        }
         default:
             break;
     }

--- a/MiCS6814_GasSensor.h	Wed May 24 13:38:46 2017 +0900
+++ b/MiCS6814_GasSensor.h	Wed May 24 10:03:01 2017 +0000
@@ -41,10 +41,9 @@
 
 #include "mbed.h"
 
-//#define _DEBUG
 #define SLAVE_ADDRESS_MiCS6814  (0x04<<1)
 
-#define ADDR_IS_SET             0           // This is read at initialization time, if 1126, set
+#define ADDR_IS_SET             0
 #define ADDR_FACTORY_ADC_NH3    2
 #define ADDR_FACTORY_ADC_CO     4
 #define ADDR_FACTORY_ADC_NO2    6
@@ -52,9 +51,7 @@
 #define ADDR_USER_ADC_HN3       8
 #define ADDR_USER_ADC_CO        10
 #define ADDR_USER_ADC_NO2       12
-#define ADDR_IF_CALI            14          // IF USER HAD CALI
-
-#define ADDR_I2C_ADDRESS        20
+#define ADDR_IF_CALI            14
 
 #define CH_VALUE_NH3            1
 #define CH_VALUE_CO             2
@@ -75,7 +72,6 @@
 #define HEATER_ON               1
 #define HEATER_OFF              0
 
-
 #ifdef _DEBUG
 extern Serial pc;
 #define DEBUG_PRINT(...) pc.printf(__VA_ARGS__)
@@ -95,16 +91,16 @@
  * Serial pc(USBTX, USBRX);
  *
  * #if defined(TARGET_LPC1768)
- * MiCS6814_GasSensor _gases(p28, p27);
+ * MiCS6814_GasSensor sensor(p28, p27);
  * #else
- * MiCS6814_GasSensor _gases(I2C_SDA, I2C_SCL);
+ * MiCS6814_GasSensor sensor(I2C_SDA, I2C_SCL);
  * #endif
  *
  * int main() {
  *
  *     while(1) {
- *         pc.printf("NH3: %.2f ppm, CO: %.2f ppm, NO2: %.2f ppm, C3H8: %.2f ppm \r\n", _gases.calcGas(NH3), _gases.calcGas(CO), _gases.calcGas(NO2), _gases.calcGas(C3H8));
- *         pc.printf("C4H10: %.2f ppm, CH4: %.2f ppm, H2: %.2f ppm, C2H5OH: %.2f ppm \r\n", _gases.calcGas(C4H10), _gases.calcGas(CH4), _gases.calcGas(H2), _gases.calcGas(C2H5OH));
+ *         pc.printf("NH3: %.2f ppm, CO: %.2f ppm, NO2: %.2f ppm, C3H8: %.2f ppm \r\n", sensor.getGas(NH3), sensor.getGas(CO), sensor.getGas(NO2), sensor.getGas(C3H8));
+ *         pc.printf("C4H10: %.2f ppm, CH4: %.2f ppm, H2: %.2f ppm, C2H5OH: %.2f ppm \r\n", sensor.getGas(C4H10), sensor.getGas(CH4), sensor.getGas(H2), sensor.getGas(C2H5OH));
  *         wait(1);
  *     }
  * }
@@ -123,19 +119,15 @@
 public:
     /** Create a MiCS6814_GasSensor instance
      *  the sensor is connected to specified I2C pins with specified address
-     *  1.Create an I2C instance
-     *  2.Initialize private variables.
      *
      * @param[in] sda I2C-bus SDA pin
      * @param[in] scl I2C-bus SCL pin
      * @param[in] slave_adr (option) I2C-bus address (default: 0x04<<1)
      */
-    MiCS6814_GasSensor(PinName sda, PinName sck, char slave_adr = SLAVE_ADDRESS_MiCS6814);
+    MiCS6814_GasSensor(PinName sda, PinName scl, char slave_adr = SLAVE_ADDRESS_MiCS6814);
 
     /** Create a MiCS6814_GasSensor instance
      *  the sensor is connected to specified I2C pins with specified address
-     *  1.Pass an I2C instance,
-     *  2.Initialize private variables.
      *
      * @param[in] i2c_obj I2C object (instance)
      * @param[in] slave_adr (option) I2C-bus address (default: 0x04<<1)
@@ -143,15 +135,11 @@
     MiCS6814_GasSensor(I2C &i2c_obj, char slave_adr = SLAVE_ADDRESS_MiCS6814);
 
     /** Destructor of MiCS6814_GasSensor
-     *  1.Power off heater
-     *  2.Release allocated heap memory.
      */
     virtual ~MiCS6814_GasSensor();
 
     /** Initialize MiCS6814_GasSensor
-     *  1.Read firmware version from sensor
-     *  2.Power on heater
-     *  3.Clear private variables
+     *  Read firmware version from sensor and power on heater
      */
     void initialize(void);
 
@@ -160,13 +148,14 @@
      *  @param[in] gas_type one of gas type defined at enum GAS_TYPE
      *  @return the measured concentration of specific gas type (ppm)
      */
-    float calcGas(const enum GAS_TYPE gas_type);
+    float getGas(const enum GAS_TYPE gas_type);
 
 private:
 
     I2C  *_i2c_p;
     I2C  &_i2c;
     char _address;       //I2C address of this MCU
+
     /** Check firmware version of sensor
      *  only support version 2
      */
@@ -194,14 +183,14 @@
      * @param[in] index  {0,1,2}
      * @return return A0_[x]
      */
-    uint16_t readR0_A0(unsigned char _indix);
+    uint16_t readR0_A0(unsigned char index);
 
     /** Read An_[x] of sensor
      *
      * @param[in] index  {0,1,2}
      * @return return An_[x]
      */
-    uint16_t readRs_An(unsigned char _indix);
+    uint16_t readRs_An(unsigned char index);
 };
 
 #endif // MBED_MULTIGAS_SENSOR_H