chris stevens
High resolution barometer and altimeter using i2c mode
Dependents: mbed_5637_test Weather_Station_Ofiicial
Fork of
ms5611
by 
Kevin Braun
Revision 8:3a9d37268ccd, committed 2014-05-20
- Comitter:
- cstevens
- Date:
- Tue May 20 16:18:00 2014 +0000
- Parent:
- 7:2e8bc98f3dda
- Commit message:
- adjusted for address but calibration not completed
Changed in this revision
diff -r 2e8bc98f3dda -r 3a9d37268ccd ms5561.cpp
--- a/ms5561.cpp Tue May 20 16:13:09 2014 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,355 +0,0 @@
-//!
-//! @file an520_I2C.c,v
-//!
-//! Copyright (c) 2009 MEAS Switzerland
-//!
-//!
-//!
-//! @brief This C code is for starter reference only. It is written for the
-//! MEAS Switzerland MS56xx pressure sensor modules and Atmel Atmega644p
-//! microcontroller.
-//!
-//! @version 1.0 $Id: an520_I2C.c,v 1.0
-//!
-//! @todo
-
-#include "mbed.h"
-#include "ms5561.h"
-
-double P; // compensated pressure value (mB)
-double T; // compensated temperature value (degC)
-double A; // altitude (ft)
-double S; // sea level barometer (mB)
-
-uint32_t C[8]; //coefficient storage
-
-//--------------------------------------------------------------------------------------------------------------------------------------//
-// Constructor and destructor
-
-ms5611::ms5611(PinName sda, PinName scl) : _i2c(sda, scl) {
- _i2c.frequency(400000);
-}
-
-//********************************************************
-//! @brief send I2C start condition and the address byte
-//!
-//! @return 0
-//********************************************************
-
-int ms5611::m_i2c_start(bool readMode) {
- int twst;
- _i2c.start();
- if(readMode == true) {
- twst = m_i2c_write(MS5611_ADDR_R);
- } else {
- twst = m_i2c_write(MS5611_ADDR_W);
- }
- return(twst);
-}
-
-//********************************************************
-//! @brief send I2C stop condition
-//!
-//! @return none
-//********************************************************
-
-void ms5611::m_i2c_stop(void) {
- _i2c.stop();
-}
-
-//********************************************************
-//! @brief send I2C stop condition
-//!
-//! @return remote ack status
-//********************************************************
-
-unsigned char ms5611::m_i2c_write(unsigned char data) {
- int twst = _i2c.write(data);
- return(twst);
-}
-
-//********************************************************
-//! @brief read I2C byte with acknowledgment
-//!
-//! @return read byte
-//********************************************************
-
-unsigned char ms5611::m_i2c_readAck(void) {
- int twst = _i2c.read(1);
- return(twst);
-}
-
-//********************************************************
-//! @brief read I2C byte without acknowledgment
-//!
-//! @return read byte
-//********************************************************
-
-unsigned char ms5611::m_i2c_readNak(void) {
- int twst = _i2c.read(0);
- return(twst);
-}
-
-//********************************************************
-//! @brief send command using I2C hardware interface
-//!
-//! @return none
-//********************************************************
-
-void ms5611::m_i2c_send(char cmd) {
- unsigned char ret;
- ret = m_i2c_start(false);
- if(!(ret)) {
- m_i2c_stop();
- } else {
- ret = m_i2c_write(cmd);
- m_i2c_stop();
- }
-}
-
-//********************************************************
-//! @brief send reset sequence
-//!
-//! @return none
-//********************************************************
-
-void ms5611::cmd_reset() {
- m_i2c_send(MS5611_CMD_RESET);
- wait_ms(4);
- loadCoefs();
-}
-
-//********************************************************
-//! @brief preform adc conversion
-//!
-//! @return 24bit result
-//********************************************************
-
-unsigned long ms5611::cmd_adc(char cmd) {
- char cobuf[3];
- cobuf[0] = 0;
- cobuf[1] = 0;
- cobuf[2] = 0;
- unsigned int ret;
- unsigned long temp = 0;
- m_i2c_send(MS5611_CMD_ADC_CONV + cmd);
- switch (cmd & 0x0f) {
- case MS5611_CMD_ADC_256 : wait_us(900); break;
- case MS5611_CMD_ADC_512 : wait_ms(3); break;
- case MS5611_CMD_ADC_1024: wait_ms(4); break;
- case MS5611_CMD_ADC_2048: wait_ms(6); break;
- case MS5611_CMD_ADC_4096: wait_ms(10); break;
- }
- m_i2c_send(MS5611_CMD_ADC_READ);
-
- ret = _i2c.read(MS5611_ADDR_R, cobuf, 3, false);
- if(ret) printf("\n*** ms5611 ADC Read Error ");
- temp = (cobuf[0] << 16) + (cobuf[1] << 8) + cobuf[2];
- return temp;
-}
-
-//********************************************************
-//! @brief Read calibration coefficients
-//!
-//! @return coefficient
-//********************************************************
-
-unsigned int ms5611::cmd_prom(char coef_num) {
- char cobuf[2];
- unsigned int ret;
- unsigned int rC = 0;
- cobuf[0] = 0;
- cobuf[1] = 0;
- m_i2c_send(MS5611_CMD_PROM_RD + coef_num * 2); // send PROM READ command
- ret = _i2c.read(MS5611_ADDR_R, cobuf, 2, false);
- if(ret) printf("\n*** ms5611 PROM Read Error ");
- rC = cobuf[0] * 256 + cobuf[1];
- return rC;
-}
-
-//********************************************************
-//! @brief calculate the CRC code
-//!
-//! @return crc code
-//********************************************************
-
-unsigned char ms5611::crc4(unsigned int n_prom[]) {
- unsigned int n_rem;
- unsigned int crc_read;
- unsigned char n_bit;
- n_rem = 0x00;
- crc_read = n_prom[7];
- n_prom[7]=(0xFF00 & (n_prom[7]));
- for (int cnt = 0; cnt < 16; cnt++) {
- if (cnt%2 == 1) {
- n_rem ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF);
- } else {
- n_rem ^= (unsigned short) (n_prom[cnt>>1]>>8);
- }
- for (n_bit = 8; n_bit > 0; n_bit--) {
- if (n_rem & (0x8000)) {
- n_rem = (n_rem << 1) ^ 0x3000;
- } else {
- n_rem = (n_rem << 1);
- }
- }
- }
- n_rem= (0x000F & (n_rem >> 12));
- n_prom[7]=crc_read;
- return (n_rem ^ 0x0);
-}
-
-/*
-The CRC code is calculated and written in factory with the LSB byte in the prom n_prom[7] set to 0x00 (see
-Coefficient table below). It is thus important to clear those bytes from the calculation buffer before proceeding
-with the CRC calculation itself:
-n_prom[7]=(0xFF00 & (n_prom[7])); //CRC byte is replaced by 0
-As a simple test of the CRC code, the following coefficient table could be used:
-unsigned int nprom[] = {0x3132,0x3334,0x3536,0x3738,0x3940,0x4142,0x4344,0x4500};
-the resulting calculated CRC should be 0xB.
-
-DB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
-Addr
-0 16 bit reserved for manufacturer
-1 Coefficient 1 (16 bit unsigned)
-2 Coefficient 2 (16 bit unsigned)
-3 Coefficient 3 (16 bit unsigned)
-4 Coefficient 4 (16 bit unsigned)
-5 Coefficient 5 (16 bit unsigned)
-6 Coefficient 6 (16 bit unsigned)
-7 0 0 0 0 CRC(0x0)
-*/
-/*
- //Returns 0x0b as per AP520_004
- C[0] = 0x3132;
- C[1] = 0x3334;
- C[2] = 0x3536;
- C[3] = 0x3738;
- C[4] = 0x3940;
- C[5] = 0x4142;
- C[6] = 0x4344;
- C[7] = 0x4546;
- n_crc = ms.crc4(C); // calculate the CRC
- pc.printf("testing CRC: 0x%x\n", n_crc);
-*/
-
-//********************************************************
-//! @brief load all calibration coefficients
-//!
-//! @return none
-//********************************************************
-
-void ms5611::loadCoefs() {
- for (int i = 0; i < 8; i++){
- wait_ms(50);
- C[i] = cmd_prom(i);
- }
- unsigned char n_crc = crc4(C);
-}
-
-//********************************************************
-//! @brief calculate temperature and pressure
-//!
-//! @return none
-//********************************************************
-
-void ms5611::calcPT() {
- int32_t D2 = cmd_adc(MS5611_CMD_ADC_D2 + MS5611_CMD_ADC_4096); // read D2
- int32_t D1 = cmd_adc(MS5611_CMD_ADC_D1 + MS5611_CMD_ADC_4096); // read D1
- int64_t dT = D2 - ((uint64_t)C[5] << 8);
- int64_t OFF = ((uint32_t)C[2] << 17) + ((dT * (C[4]) >> 6)); //was OFF = (C[2] << 17) + dT * C[4] / (1 << 6);
- int64_t SENS = ((uint32_t)C[1] << 16) + ((dT * (C[3]) >> 7)); //was SENS = (C[1] << 16) + dT * C[3] / (1 << 7);
- //T = (2000 + (((uint64_t)dT * C[6]) / (float)(1 << 23))) / 100;
- T=(2000+(dT*C[6])/8388608)/100;
- //int32_t TEMP = 2000 + (int64_t)dT * (int64_t)C[6] / (int64_t)(1 << 23);
- int32_t TEMP = 2000 + (int64_t)dT * (int64_t)(C[6] >> 23);
- if(TEMP < 2000) { // if temperature lower than 20 Celsius
- float T1 = (TEMP - 2000) * (TEMP - 2000);
- int64_t OFF1 = (61 * T1) / 16;
- int64_t SENS1 = (29 * T1) / 16;
-
- if(TEMP < -1500) { // if temperature lower than -15 Celsius
- T1 = (TEMP + 1500) * (TEMP + 1500);
- OFF1 += 17 * T1;
- SENS1 += 9 * T1 ;
- }
- OFF -= OFF1;
- SENS -= SENS1;
- T = (float)TEMP / 100;
- }
-// int64_t P1 = ((((int64_t)D1 * SENS) >> 21) - OFF) >> 15;
- //P = ((((int64_t)D1 * SENS ) >> 21) - OFF) / (double) (1 << 15) / 100.0;
- P=(D1*SENS/2097152-OFF)/3276800;
-}
-
-//********************************************************
-//! @brief calculate temperature
-//!
-//! @return double temperature degC
-//********************************************************
-
-double ms5611::calcTemp() {
- calcPT();
- return(T);
-}
-
-//********************************************************
-//! @brief calculate pressure
-//!
-//! @return double barometric pressure millibar
-//********************************************************
-
-double ms5611::calcPressure() {
- calcPT();
- return(P);
-}
-
-//********************************************************
-//! @brief get pressure, no calculation
-//!
-//! @return double barometric pressure millibar
-//********************************************************
-
-double ms5611::getPressure() {
- calcPT();
- return(P);
-}
-
-//********************************************************
-//! @brief get altitude from known sea level barometer,
-//! @ no pre-pressure calculation
-//!
-//! @enter float sea level barometer
-//! @return float altitude in feet
-//********************************************************
-
-float ms5611::getAltitudeFT(float sea_pressure) {
- A = (1 - (pow((P / (double)sea_pressure), 0.190284))) * 145366.45;
- return((float)A);
-}
-
-//********************************************************
-//! @brief get sea level pressure from known altitude(ft),
-//! @ no pre-pressure calculation
-//!
-//! @enter float known altitude in feet
-//! @return float seal level barometer in mb
-//********************************************************
-
-float ms5611::getSeaLevelBaroFT(float known_alt) {
- S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt , 5.2553026) * MB;
- return((float)S);
-}
-
-//********************************************************
-//! @brief get sea level pressure from known altitude(m),
-//! @ no pre-pressure calculation
-//!
-//! @enter float known altitude in meters
-//! @return float seal level barometer in mb
-//********************************************************
-
-float ms5611::getSeaLevelBaroM(float known_alt) {
- S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt * FTMETERS , 5.2553026) * MB;
- return((float)S);
-}
diff -r 2e8bc98f3dda -r 3a9d37268ccd ms5561.h
--- a/ms5561.h Tue May 20 16:13:09 2014 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,171 +0,0 @@
-#ifndef MS5561H
-#define MS5561_H
-
-#include "mbed.h"
-
-
-#define SEA_PRESS 1013.25 //default sea level pressure level in mb
-#define KNOWNALT 327.0 //default known altitude, 5200 Franklin Dr., 94588
-#define INHG 0.02952998751 //convert mb to in/Hg constant
-#define MB 33.8638815 //convert in/Hg to mb constant
-#define FTMETERS 0.3048 //convert feet to meters
-
-
-/** Software routines to access the Measurement Specialties' MS5611-01BA03
- * Variometer Module using the I2C bus option. The MS5611 is a 24 bit
- * temperature and pressure transducer for high accuracy Barometer and
- * Altimeter applications. It also includes compensation coefficients
- * stored within the device.
- *
- * Code adapted from Measurement Specialties:
- * "AN520 C-code example for MS56xx, MS57xx (except analog sensor), and
- * MS58xx series pressure sensors"
- *
- * Note: AN520 has not been updated for use with the MS5611. Changes
- * were necessary to "calcPT()" in order to correct scaling of
- * pressure readings.
- *
- * Features:
- * Altitude resolution to 10cm
- * Fast conversion down to 1 ms
- * Low power, 1 μA (standby < 0.15 μA)
- * QFN package 5.0 x 3.0 x 1.0 mm^3
- * Supply voltage 1.8 to 3.6 V
- * Integrated digital pressure sensor (24 bit DeltaSigma ADC)
- * Operating range: 10 to 1200 mbar, -40 to +85 °C
- * I2C and SPI interface up to 20 MHz
- * No external components (Internal oscillator)
- * Excellent long term stability
- *
- * @code
- * #include "mbed.h"
- * #include "ms5611.h"
- *
- * ms5611 ms(p9, p10); // i2c pins used
- * Serial pc(USBTX, USBRX); // local terminal interface
- *
- *
- * int main (void) {
- * pc.baud(921600); // set up USB serial speed
- *
- * // set up the ms5611
- * pc.printf("\n\nInitializing the MS5611..\n");
- * ms.cmd_reset();
- * pc.printf("Ready\n");
- *
- * while(1) {
- * double Temp = ms.calcTemp(); //calculate press and temp, then returns current temperature in degC
- * double Press = ms.calcPressure(); //calculate press and temp, then returns current pressure in mb
- * double GetPress = ms.getPressure(); //returns current pressure in mb. Does no calculations. Ususally done after calcTemp()
- * double Altitude = ms.getAltitudeFT(1013.25); //enter pressure at sea level in mb, returns altitude in feet
- * double PressSeaLvlFT = ms.getSeaLevelBaroFT(327.2); //enter known altitude in feet, returns sea level pressure in mb
- * double PressSeaLvlM = ms.getAltitudeFT(99.73); //enter known altitude in meters, returns seal level pressure in mb
- *
- * pc.printf("Temp: %.2f degC\n", Temp);
- * pc.printf("Barometer: %.1f mB %.3f in/Hg\n", Press, Press * 0.0295301);
- * pc.printf("Alt: %.1f ft\n", Altitude);
- * pc.printf("Sea_Lvl: %.1f ft %.2f m\n", PressSeaLvlFT, PressSeaLvlM);
- * wait(2.0);
- * }
- * }
- *
- * @endcode
- */
-
-//_____ M A C R O S
-
-#define MS5611_ADDR_W 0xEC // Module address write mode CHANGED FOR 5561 ORIGINAL 0Xee
-#define MS5611_ADDR_R 0xED // Module address read modeCHANGED FOR 5561 ORIGINAL 0XeF
-#define MS5611_CMD_RESET 0x1E // ADC reset command
-#define MS5611_CMD_ADC_READ 0x00 // ADC read command
-#define MS5611_CMD_ADC_CONV 0x40 // ADC conversion command
-#define MS5611_CMD_ADC_D1 0x00 // ADC D1 conversion
-#define MS5611_CMD_ADC_D2 0x10 // ADC D2 conversion
-#define MS5611_CMD_ADC_256 0x00 // ADC OSR=256
-#define MS5611_CMD_ADC_512 0x02 // ADC OSR=512
-#define MS5611_CMD_ADC_1024 0x04 // ADC OSR=1024
-#define MS5611_CMD_ADC_2048 0x06 // ADC OSR=2048
-#define MS5611_CMD_ADC_4096 0x08 // ADC OSR=4096
-#define MS5611_CMD_PROM_RD 0xA0 // Prom read command
-
- /** Create ms5611 controller class
- *
- * @param ms5611 class
- *
- */
-class ms5611 {
-
-public:
- /** Create a MS5611 object using the specified I2C object
- *
- * @param constructor, - the I2C object to communicate with
- */
- ms5611(PinName sda, PinName scl);
- /** Initialize the MS5611 and set up the coefficients
- * First - reset the MS5611
- * Second - load coefficient values from the MS5611 PROM
- * Third - calculate coefficient checksum
- * This routine only needs to be run once at boot up
- *
- * @param NONE
- */
- void cmd_reset();
- /** Calculate and return compensated temperature
- * Returns double temperature in degC
- *
- * @param NONE
- */
- double calcTemp();
- /** Calculate and return compensated barometric pressure
- * Returns double pressure in millibars
- *
- * @param NONE
- */
- double calcPressure();
- /** Return compensated barometric pressure
- * Returns double pressure in millibars
- * DOES NOT RE-CALCULATE FIRST!!!
- * Saves time if you calcTemp(); first
- *
- * @param NONE
- */
- double getPressure();
- /** Calculate and returns altitude in feet
- * Returns float altitude in feet
- *
- * @param float known pressure (mB) at sea level
- */
- float getAltitudeFT(float sea_pressure);
- /** Calculate and returns sea level baro
- * Returns float seal level barometer in feet
- *
- * @param float known altitude in feet
- */
- float getSeaLevelBaroFT(float known_alt);
- /** Calculate and returns sea level baro
- * Returns float seal level barometer in meters
- *
- * @param float known altitude in meters
- */
- float getSeaLevelBaroM(float known_alt);
-
-private:
- int m_i2c_start(bool readMode);
- void m_i2c_stop(void);
- unsigned char m_i2c_write(unsigned char data);
- unsigned char m_i2c_readAck(void);
- unsigned char m_i2c_readNak(void);
- void m_i2c_send(char cmd);
- void loadCoefs();
- unsigned long cmd_adc(char cmd);
- unsigned int cmd_prom(char coef_num);
- unsigned char crc4(unsigned n_prom[]);
- void calcPT();
- unsigned int PTbuffer[8]; // calibration coefficients
-
-protected:
- I2C _i2c;
-
-
-};
-#endif
diff -r 2e8bc98f3dda -r 3a9d37268ccd ms5637.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ms5637.cpp Tue May 20 16:18:00 2014 +0000
@@ -0,0 +1,355 @@
+//!
+//! @file an520_I2C.c,v
+//!
+//! Copyright (c) 2009 MEAS Switzerland
+//!
+//!
+//!
+//! @brief This C code is for starter reference only. It is written for the
+//! MEAS Switzerland MS56xx pressure sensor modules and Atmel Atmega644p
+//! microcontroller.
+//!
+//! @version 1.0 $Id: an520_I2C.c,v 1.0
+//!
+//! @todo
+
+#include "mbed.h"
+#include "ms5637.h"
+
+double P; // compensated pressure value (mB)
+double T; // compensated temperature value (degC)
+double A; // altitude (ft)
+double S; // sea level barometer (mB)
+
+uint32_t C[8]; //coefficient storage
+
+//--------------------------------------------------------------------------------------------------------------------------------------//
+// Constructor and destructor
+
+ms5637::ms5637(PinName sda, PinName scl) : _i2c(sda, scl) {
+ _i2c.frequency(400000);
+}
+
+//********************************************************
+//! @brief send I2C start condition and the address byte
+//!
+//! @return 0
+//********************************************************
+
+int ms5637::m_i2c_start(bool readMode) {
+ int twst;
+ _i2c.start();
+ if(readMode == true) {
+ twst = m_i2c_write(MS5637_ADDR_R);
+ } else {
+ twst = m_i2c_write(MS5637_ADDR_W);
+ }
+ return(twst);
+}
+
+//********************************************************
+//! @brief send I2C stop condition
+//!
+//! @return none
+//********************************************************
+
+void ms5637::m_i2c_stop(void) {
+ _i2c.stop();
+}
+
+//********************************************************
+//! @brief send I2C stop condition
+//!
+//! @return remote ack status
+//********************************************************
+
+unsigned char ms5637::m_i2c_write(unsigned char data) {
+ int twst = _i2c.write(data);
+ return(twst);
+}
+
+//********************************************************
+//! @brief read I2C byte with acknowledgment
+//!
+//! @return read byte
+//********************************************************
+
+unsigned char ms5637::m_i2c_readAck(void) {
+ int twst = _i2c.read(1);
+ return(twst);
+}
+
+//********************************************************
+//! @brief read I2C byte without acknowledgment
+//!
+//! @return read byte
+//********************************************************
+
+unsigned char ms5637::m_i2c_readNak(void) {
+ int twst = _i2c.read(0);
+ return(twst);
+}
+
+//********************************************************
+//! @brief send command using I2C hardware interface
+//!
+//! @return none
+//********************************************************
+
+void ms5637::m_i2c_send(char cmd) {
+ unsigned char ret;
+ ret = m_i2c_start(false);
+ if(!(ret)) {
+ m_i2c_stop();
+ } else {
+ ret = m_i2c_write(cmd);
+ m_i2c_stop();
+ }
+}
+
+//********************************************************
+//! @brief send reset sequence
+//!
+//! @return none
+//********************************************************
+
+void ms5637::cmd_reset() {
+ m_i2c_send(MS5637_CMD_RESET);
+ wait_ms(4);
+ loadCoefs();
+}
+
+//********************************************************
+//! @brief preform adc conversion
+//!
+//! @return 24bit result
+//********************************************************
+
+unsigned long ms5637::cmd_adc(char cmd) {
+ char cobuf[3];
+ cobuf[0] = 0;
+ cobuf[1] = 0;
+ cobuf[2] = 0;
+ unsigned int ret;
+ unsigned long temp = 0;
+ m_i2c_send(MS5637_CMD_ADC_CONV + cmd);
+ switch (cmd & 0x0f) {
+ case MS5637_CMD_ADC_256 : wait_us(900); break;
+ case MS5637_CMD_ADC_512 : wait_ms(3); break;
+ case MS5637_CMD_ADC_1024: wait_ms(4); break;
+ case MS5637_CMD_ADC_2048: wait_ms(6); break;
+ case MS5637_CMD_ADC_4096: wait_ms(10); break;
+ }
+ m_i2c_send(MS5637_CMD_ADC_READ);
+
+ ret = _i2c.read(MS5637_ADDR_R, cobuf, 3, false);
+ if(ret) printf("\n*** ms5637 ADC Read Error ");
+ temp = (cobuf[0] << 16) + (cobuf[1] << 8) + cobuf[2];
+ return temp;
+}
+
+//********************************************************
+//! @brief Read calibration coefficients
+//!
+//! @return coefficient
+//********************************************************
+
+unsigned int ms5637::cmd_prom(char coef_num) {
+ char cobuf[2];
+ unsigned int ret;
+ unsigned int rC = 0;
+ cobuf[0] = 0;
+ cobuf[1] = 0;
+ m_i2c_send(MS5637_CMD_PROM_RD + coef_num * 2); // send PROM READ command
+ ret = _i2c.read(MS5637_ADDR_R, cobuf, 2, false);
+ if(ret) printf("\n*** ms5637 PROM Read Error ");
+ rC = cobuf[0] * 256 + cobuf[1];
+ return rC;
+}
+
+//********************************************************
+//! @brief calculate the CRC code
+//!
+//! @return crc code
+//********************************************************
+
+unsigned char ms5637::crc4(unsigned int n_prom[]) {
+ unsigned int n_rem;
+ unsigned int crc_read;
+ unsigned char n_bit;
+ n_rem = 0x00;
+ crc_read = n_prom[7];
+ n_prom[7]=(0xFF00 & (n_prom[7]));
+ for (int cnt = 0; cnt < 16; cnt++) {
+ if (cnt%2 == 1) {
+ n_rem ^= (unsigned short) ((n_prom[cnt>>1]) & 0x00FF);
+ } else {
+ n_rem ^= (unsigned short) (n_prom[cnt>>1]>>8);
+ }
+ for (n_bit = 8; n_bit > 0; n_bit--) {
+ if (n_rem & (0x8000)) {
+ n_rem = (n_rem << 1) ^ 0x3000;
+ } else {
+ n_rem = (n_rem << 1);
+ }
+ }
+ }
+ n_rem= (0x000F & (n_rem >> 12));
+ n_prom[7]=crc_read;
+ return (n_rem ^ 0x0);
+}
+
+/*
+The CRC code is calculated and written in factory with the LSB byte in the prom n_prom[7] set to 0x00 (see
+Coefficient table below). It is thus important to clear those bytes from the calculation buffer before proceeding
+with the CRC calculation itself:
+n_prom[7]=(0xFF00 & (n_prom[7])); //CRC byte is replaced by 0
+As a simple test of the CRC code, the following coefficient table could be used:
+unsigned int nprom[] = {0x3132,0x3334,0x3536,0x3738,0x3940,0x4142,0x4344,0x4500};
+the resulting calculated CRC should be 0xB.
+
+DB 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+Addr
+0 16 bit reserved for manufacturer
+1 Coefficient 1 (16 bit unsigned)
+2 Coefficient 2 (16 bit unsigned)
+3 Coefficient 3 (16 bit unsigned)
+4 Coefficient 4 (16 bit unsigned)
+5 Coefficient 5 (16 bit unsigned)
+6 Coefficient 6 (16 bit unsigned)
+7 0 0 0 0 CRC(0x0)
+*/
+/*
+ //Returns 0x0b as per AP520_004
+ C[0] = 0x3132;
+ C[1] = 0x3334;
+ C[2] = 0x3536;
+ C[3] = 0x3738;
+ C[4] = 0x3940;
+ C[5] = 0x4142;
+ C[6] = 0x4344;
+ C[7] = 0x4546;
+ n_crc = ms.crc4(C); // calculate the CRC
+ pc.printf("testing CRC: 0x%x\n", n_crc);
+*/
+
+//********************************************************
+//! @brief load all calibration coefficients
+//!
+//! @return none
+//********************************************************
+
+void ms5637::loadCoefs() {
+ for (int i = 0; i < 8; i++){
+ wait_ms(50);
+ C[i] = cmd_prom(i);
+ }
+ unsigned char n_crc = crc4(C);
+}
+
+//********************************************************
+//! @brief calculate temperature and pressure
+//!
+//! @return none
+//********************************************************
+
+void ms5637::calcPT() {
+ int32_t D2 = cmd_adc(MS5637_CMD_ADC_D2 + MS5637_CMD_ADC_4096); // read D2
+ int32_t D1 = cmd_adc(MS5637_CMD_ADC_D1 + MS5637_CMD_ADC_4096); // read D1
+ int64_t dT = D2 - ((uint64_t)C[5] << 8);
+ int64_t OFF = ((uint32_t)C[2] << 17) + ((dT * (C[4]) >> 6)); //was OFF = (C[2] << 17) + dT * C[4] / (1 << 6);
+ int64_t SENS = ((uint32_t)C[1] << 16) + ((dT * (C[3]) >> 7)); //was SENS = (C[1] << 16) + dT * C[3] / (1 << 7);
+ //T = (2000 + (((uint64_t)dT * C[6]) / (float)(1 << 23))) / 100;
+ T=(2000+(dT*C[6])/8388608)/100;
+ //int32_t TEMP = 2000 + (int64_t)dT * (int64_t)C[6] / (int64_t)(1 << 23);
+ int32_t TEMP = 2000 + (int64_t)dT * (int64_t)(C[6] >> 23);
+ if(TEMP < 2000) { // if temperature lower than 20 Celsius
+ float T1 = (TEMP - 2000) * (TEMP - 2000);
+ int64_t OFF1 = (61 * T1) / 16;
+ int64_t SENS1 = (29 * T1) / 16;
+
+ if(TEMP < -1500) { // if temperature lower than -15 Celsius
+ T1 = (TEMP + 1500) * (TEMP + 1500);
+ OFF1 += 17 * T1;
+ SENS1 += 9 * T1 ;
+ }
+ OFF -= OFF1;
+ SENS -= SENS1;
+ T = (float)TEMP / 100;
+ }
+// int64_t P1 = ((((int64_t)D1 * SENS) >> 21) - OFF) >> 15;
+ //P = ((((int64_t)D1 * SENS ) >> 21) - OFF) / (double) (1 << 15) / 100.0;
+ P=(D1*SENS/2097152-OFF)/3276800;
+}
+
+//********************************************************
+//! @brief calculate temperature
+//!
+//! @return double temperature degC
+//********************************************************
+
+double ms5637::calcTemp() {
+ calcPT();
+ return(T);
+}
+
+//********************************************************
+//! @brief calculate pressure
+//!
+//! @return double barometric pressure millibar
+//********************************************************
+
+double ms5637::calcPressure() {
+ calcPT();
+ return(P);
+}
+
+//********************************************************
+//! @brief get pressure, no calculation
+//!
+//! @return double barometric pressure millibar
+//********************************************************
+
+double ms5637::getPressure() {
+ calcPT();
+ return(P);
+}
+
+//********************************************************
+//! @brief get altitude from known sea level barometer,
+//! @ no pre-pressure calculation
+//!
+//! @enter float sea level barometer
+//! @return float altitude in feet
+//********************************************************
+
+float ms5637::getAltitudeFT(float sea_pressure) {
+ A = (1 - (pow((P / (double)sea_pressure), 0.190284))) * 145366.45;
+ return((float)A);
+}
+
+//********************************************************
+//! @brief get sea level pressure from known altitude(ft),
+//! @ no pre-pressure calculation
+//!
+//! @enter float known altitude in feet
+//! @return float seal level barometer in mb
+//********************************************************
+
+float ms5637::getSeaLevelBaroFT(float known_alt) {
+ S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt , 5.2553026) * MB;
+ return((float)S);
+}
+
+//********************************************************
+//! @brief get sea level pressure from known altitude(m),
+//! @ no pre-pressure calculation
+//!
+//! @enter float known altitude in meters
+//! @return float seal level barometer in mb
+//********************************************************
+
+float ms5637::getSeaLevelBaroM(float known_alt) {
+ S = pow(pow((P * INHG), 0.190284) + 0.00001313 * known_alt * FTMETERS , 5.2553026) * MB;
+ return((float)S);
+}
diff -r 2e8bc98f3dda -r 3a9d37268ccd ms5637.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ms5637.h Tue May 20 16:18:00 2014 +0000
@@ -0,0 +1,171 @@
+#ifndef MS5637H
+#define MS5637_H
+
+#include "mbed.h"
+
+
+#define SEA_PRESS 1013.25 //default sea level pressure level in mb
+#define KNOWNALT 327.0 //default known altitude, 5200 Franklin Dr., 94588
+#define INHG 0.02952998751 //convert mb to in/Hg constant
+#define MB 33.8638815 //convert in/Hg to mb constant
+#define FTMETERS 0.3048 //convert feet to meters
+
+
+/** Software routines to access the Measurement Specialties' MS5637-01BA03
+ * Variometer Module using the I2C bus option. The MS5637 is a 24 bit
+ * temperature and pressure transducer for high accuracy Barometer and
+ * Altimeter applications. It also includes compensation coefficients
+ * stored within the device.
+ *
+ * Code adapted from Measurement Specialties:
+ * "AN520 C-code example for MS56xx, MS57xx (except analog sensor), and
+ * MS58xx series pressure sensors"
+ *
+ * Note: AN520 has not been updated for use with the MS5637. Changes
+ * were necessary to "calcPT()" in order to correct scaling of
+ * pressure readings.
+ *
+ * Features:
+ * Altitude resolution to 10cm
+ * Fast conversion down to 1 ms
+ * Low power, 1 μA (standby < 0.15 μA)
+ * QFN package 5.0 x 3.0 x 1.0 mm^3
+ * Supply voltage 1.8 to 3.6 V
+ * Integrated digital pressure sensor (24 bit DeltaSigma ADC)
+ * Operating range: 10 to 1200 mbar, -40 to +85 °C
+ * I2C and SPI interface up to 20 MHz
+ * No external components (Internal oscillator)
+ * Excellent long term stability
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "ms5637.h"
+ *
+ * ms5637 ms(p9, p10); // i2c pins used
+ * Serial pc(USBTX, USBRX); // local terminal interface
+ *
+ *
+ * int main (void) {
+ * pc.baud(921600); // set up USB serial speed
+ *
+ * // set up the ms5637
+ * pc.printf("\n\nInitializing the MS5637..\n");
+ * ms.cmd_reset();
+ * pc.printf("Ready\n");
+ *
+ * while(1) {
+ * double Temp = ms.calcTemp(); //calculate press and temp, then returns current temperature in degC
+ * double Press = ms.calcPressure(); //calculate press and temp, then returns current pressure in mb
+ * double GetPress = ms.getPressure(); //returns current pressure in mb. Does no calculations. Ususally done after calcTemp()
+ * double Altitude = ms.getAltitudeFT(1013.25); //enter pressure at sea level in mb, returns altitude in feet
+ * double PressSeaLvlFT = ms.getSeaLevelBaroFT(327.2); //enter known altitude in feet, returns sea level pressure in mb
+ * double PressSeaLvlM = ms.getAltitudeFT(99.73); //enter known altitude in meters, returns seal level pressure in mb
+ *
+ * pc.printf("Temp: %.2f degC\n", Temp);
+ * pc.printf("Barometer: %.1f mB %.3f in/Hg\n", Press, Press * 0.0295301);
+ * pc.printf("Alt: %.1f ft\n", Altitude);
+ * pc.printf("Sea_Lvl: %.1f ft %.2f m\n", PressSeaLvlFT, PressSeaLvlM);
+ * wait(2.0);
+ * }
+ * }
+ *
+ * @endcode
+ */
+
+//_____ M A C R O S
+
+#define MS5637_ADDR_W 0xEC // Module address write mode CHANGED FOR 5637 ORIGINAL 0Xee
+#define MS5637_ADDR_R 0xED // Module address read modeCHANGED FOR 5637 ORIGINAL 0XeF
+#define MS5637_CMD_RESET 0x1E // ADC reset command
+#define MS5637_CMD_ADC_READ 0x00 // ADC read command
+#define MS5637_CMD_ADC_CONV 0x40 // ADC conversion command
+#define MS5637_CMD_ADC_D1 0x00 // ADC D1 conversion
+#define MS5637_CMD_ADC_D2 0x10 // ADC D2 conversion
+#define MS5637_CMD_ADC_256 0x00 // ADC OSR=256
+#define MS5637_CMD_ADC_512 0x02 // ADC OSR=512
+#define MS5637_CMD_ADC_1024 0x04 // ADC OSR=1024
+#define MS5637_CMD_ADC_2048 0x06 // ADC OSR=2048
+#define MS5637_CMD_ADC_4096 0x08 // ADC OSR=4096
+#define MS5637_CMD_PROM_RD 0xA0 // Prom read command
+
+ /** Create ms5637 controller class
+ *
+ * @param ms5637 class
+ *
+ */
+class ms5637 {
+
+public:
+ /** Create a MS5637 object using the specified I2C object
+ *
+ * @param constructor, - the I2C object to communicate with
+ */
+ ms5637(PinName sda, PinName scl);
+ /** Initialize the MS5637 and set up the coefficients
+ * First - reset the MS5637
+ * Second - load coefficient values from the MS5637 PROM
+ * Third - calculate coefficient checksum
+ * This routine only needs to be run once at boot up
+ *
+ * @param NONE
+ */
+ void cmd_reset();
+ /** Calculate and return compensated temperature
+ * Returns double temperature in degC
+ *
+ * @param NONE
+ */
+ double calcTemp();
+ /** Calculate and return compensated barometric pressure
+ * Returns double pressure in millibars
+ *
+ * @param NONE
+ */
+ double calcPressure();
+ /** Return compensated barometric pressure
+ * Returns double pressure in millibars
+ * DOES NOT RE-CALCULATE FIRST!!!
+ * Saves time if you calcTemp(); first
+ *
+ * @param NONE
+ */
+ double getPressure();
+ /** Calculate and returns altitude in feet
+ * Returns float altitude in feet
+ *
+ * @param float known pressure (mB) at sea level
+ */
+ float getAltitudeFT(float sea_pressure);
+ /** Calculate and returns sea level baro
+ * Returns float seal level barometer in feet
+ *
+ * @param float known altitude in feet
+ */
+ float getSeaLevelBaroFT(float known_alt);
+ /** Calculate and returns sea level baro
+ * Returns float seal level barometer in meters
+ *
+ * @param float known altitude in meters
+ */
+ float getSeaLevelBaroM(float known_alt);
+
+private:
+ int m_i2c_start(bool readMode);
+ void m_i2c_stop(void);
+ unsigned char m_i2c_write(unsigned char data);
+ unsigned char m_i2c_readAck(void);
+ unsigned char m_i2c_readNak(void);
+ void m_i2c_send(char cmd);
+ void loadCoefs();
+ unsigned long cmd_adc(char cmd);
+ unsigned int cmd_prom(char coef_num);
+ unsigned char crc4(unsigned n_prom[]);
+ void calcPT();
+ unsigned int PTbuffer[8]; // calibration coefficients
+
+protected:
+ I2C _i2c;
+
+
+};
+#endif