MS5803.cpp

00001 /*
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00003     of this software and associated documentation files (the "Software"), to deal
00004     in the Software without restriction, including without limitation the rights
00005     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00006     copies of the Software, and to permit persons to whom the Software is
00007     furnished to do so, subject to the following conditions:
00008 
00009     The above copyright notice and this permission notice shall be included in
00010     all copies or substantial portions of the Software.
00011 
00012     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00013     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00014     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00015     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00016     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
00018     THE SOFTWARE.
00019 
00020   * Library for Pressure Sensors of type MS5803-x of MEAS Switzerland     (www.meas-spec.com).
00021   * The driver uses I2C mode (sensor's Protocol Select (PS) pin pulled to high).
00022   * MS5803-01BA was successfully tested by Raig Kaufer.
00023   * MS5803-14BA (Underwater Pressure Sensor 14 bar) was successfully tested by Robert Katzschmann
00024   * Other types of MEAS are compatible but not tested
00025   * Written by Raig Kaufer, distribute freely!
00026   * Revised by Robert Katzschmann
00027  */
00028 
00029 #include <stdlib.h>
00030 #include "MS5803.h"
00031 
00032 
00033 /*
00034  * Sensor operating function according data sheet
00035  */
00036 
00037 void MS5803::MS5803Init(void)
00038 {
00039     MS5803Reset();
00040     MS5803ReadProm();
00041     return;
00042 }
00043 
00044 /* Send soft reset to the sensor */
00045 void MS5803::MS5803Reset(void)
00046 {
00047     /* transmit out 1 byte reset command */
00048     ms5803_tx_data[0] = ms5803_reset;
00049     if ( i2c.write( device_address,  ms5803_tx_data, 1 ) );
00050     //printf("send soft reset");
00051     wait_ms(20);
00052 }
00053 
00054 /* read the sensor calibration data from rom */
00055 void MS5803::MS5803ReadProm(void)
00056 {
00057     uint8_t i,j;
00058     for (i=0; i<8; i++) {
00059         j = i;
00060         ms5803_tx_data[0] = ms5803_PROMread + (j<<1);
00061         if ( i2c.write( device_address,  ms5803_tx_data, 1 ) );
00062         if ( i2c.read( device_address,  ms5803_rx_data, 2 ) );
00063         C[i]   = (unsigned short) ((unsigned int)ms5803_rx_data[1] + (((unsigned int)ms5803_rx_data[0])<<8));
00064     }
00065 }
00066 
00067 /* Start the sensor pressure conversion */
00068 void MS5803::MS5803ConvertD1(void)
00069 {
00070     ms5803_tx_data[0] = ms5803_convD1;
00071     if ( i2c.write( device_address,  ms5803_tx_data, 1 ) );
00072 }
00073 
00074 /* Start the sensor temperature conversion */
00075 void MS5803:: MS5803ConvertD2(void)
00076 {
00077     ms5803_tx_data[0] = ms5803_convD2;
00078     if ( i2c.write( device_address,  ms5803_tx_data, 1 ) );
00079 }
00080 
00081 /* Read the previous started conversion results */
00082 int32_t MS5803::MS5803ReadADC(void)
00083 {
00084     int32_t adc;
00085     wait_ms(150);
00086     ms5803_tx_data[0] = ms5803_ADCread;
00087     if ( i2c.write( device_address,  ms5803_tx_data, 1 ) );
00088     if ( i2c.read( device_address,  ms5803_rx_data, 3 ) );
00089     adc = (unsigned int)ms5803_rx_data[2] + (((unsigned int)ms5803_rx_data[1])<<8) + (((unsigned int)ms5803_rx_data[0])<<16);
00090     return (adc);
00091 }
00092 
00093 /* return the results */
00094 float MS5803::MS5803_Pressure (void)
00095 {
00096     return P_MS5803;
00097 }
00098 float MS5803::MS5803_Temperature (void)
00099 {
00100     return T_MS5803;
00101 }
00102 
00103 /* Sensor reading and calculation procedure */
00104 void MS5803::Barometer_MS5803(void)
00105 {
00106     int32_t dT, temp;
00107     int64_t OFF, SENS, press;
00108 
00109     //no need to do this everytime!
00110     //MS5803Reset();                 // reset the sensor
00111     //MS5803ReadProm();             // read the calibration values
00112     
00113     
00114     MS5803ConvertD1();             // start pressure conversion
00115     D1 = MS5803ReadADC();        // read the pressure value
00116     MS5803ConvertD2();             // start temperature conversion
00117     D2 = MS5803ReadADC();         // read the temperature value
00118 
00119     /* calculation according MS5803-01BA data sheet DA5803-01BA_006 */
00120     dT       = D2 - (C[5]* 256);
00121  //   OFF      = (int64_t)C[2] * (1<<18) + ((int64_t)dT * (int64_t)C[4]) / (1<<5);
00122  //   SENS     = (int64_t)C[1] * (1<<17) + ((int64_t)dT * (int64_t)C[3]) / (1<<6);
00123     OFF      = (int64_t)C[2] * (1<<16) + ((int64_t)dT * (int64_t)C[4]) / (1<<7);
00124     SENS     = (int64_t)C[1] * (1<<15) + ((int64_t)dT * (int64_t)C[3]) / (1<<8);
00125 
00126     temp     = 2000 + ((int64_t)dT * C[6]) / (1<<23);
00127     T_MS5803 = (float) temp / 100.0f;                 // result of temperature in deg C in this var
00128     press    = ((( (((int64_t)D1)&0xFFFFFFFF) * SENS) / (1<<21) - OFF)) / (1<<15);
00129     P_MS5803 = (float)press / 10.;                 // result of pressure in mBar in this var
00130 }