Arduino Mega 2560 Board. MS5607 Altimeter.
Here is the data sheet for this device. Pages 8 and 9 are what I’m using. Very nicely laid out…
I am having immense problems with getting the correct pressure. Pressure is coming out as negative. Everything else in the program works correctly. Any thoughts as to what I can try to get this thing work? All help greatly appreciated. Thanks.
#include <Wire.h>
#define ADDRESS 0x76 //0x77
#include "IntersemaBaro.h"
Intersema::BaroPressure_MS5607B baro(true);
uint32_t D1 = 0;
uint32_t D2 = 0;
int32_t dT = 0;
int32_t TEMP = 0;
int64_t OFF = 0;
int64_t SENS = 0;
int32_t P = 0;
int32_t I = 4430.76923;
int32_t Altitude;
int32_t P0;
uint16_t C[7];
int32_t ALTITUDE;
const float sea_press = 1013.25;
float Temperature;
float Pressure;
void setup() {
baro.init();
// Disable internal pullups, 10Kohms are on the breakout
PORTC |= (1 << 4);
PORTC |= (1 << 5);
Wire.begin();
Serial.begin(9600); //9600 changed 'cos of timing?
delay(100);
initial(ADDRESS);
}
void loop()
{
int32_t T2; //signed int 32 bit for T2 (used for Temperature compensation)
int64_t OFF2; //signed int 64 bit for OFF2 (used for Temperature compesation [see flow chart])
int64_t SENS2; //signed int 64 bit for SENS2 (used for Temperature compensation [see flow chart])
D1 = getVal(ADDRESS, 0x48); // Pressure raw
D2 = getVal(ADDRESS, 0x58);// raw temperature value
//dT and Temp will calculate temperature
dT = D2 - ((uint64_t)C[5] *(2*2*2*2*2*2*2*2));
//off and sens will calculate temperature compensated pressure
OFF = ( (int64_t)C[2]*131072 ) + ( (dT * C[4]) / (64));
SENS = ( (int32_t)C[1]*65536 ) + ( (dT * C[3]) / (128));
TEMP = 2000 + (dT * (int64_t)C[6] / (8388608) ); //base temperature formula
Serial.print(" TEMP= ");
Serial.print(TEMP);
if(TEMP <2000) // FOR WHEN THE TEMPERATURE IS BELOW 20 CELSIUS
{
Serial.print("Made pass through low temp\n");
T2=-(dT*dT)/(pow(2,31));
OFF2= (61*(TEMP-2000)*(TEMP-2000))/16;
SENS2 = 2*(TEMP-2000)*(TEMP-2000);
}
if(TEMP>2000) //FOR WHEN THE TEMPERATURE IS ABOVE 20 CELSIUS
{
T2=0;
OFF2=0;
SENS2 =0;
}
TEMP -= T2;
OFF -= OFF2;
SENS -= SENS2;
Temperature = (float)TEMP / 100;
P = ((int64_t)D1 * SENS / 2097152 - OFF) / 32768;
Pressure = ((float)P / 100);
Serial.print(" Actual TEMP= ");
Serial.print(Temperature);
Serial.print(" Actual PRESSURE= ");
Serial.print(Pressure);
int alt = baro.getHeightCentiMeters();
Serial.print(" CODE FROM PARALLAX FOR ALTITUDE \n");
Serial.print(" Feet: ");
Serial.println((float)(alt)/30.48);
Serial.print(" \n");
delay(1000);
Serial.println();
delay(1000);
}
long getVal(int address, byte code)
{
unsigned long ret = 0;
Wire.beginTransmission(address);
Wire.write(code);
Wire.endTransmission();
delay(10);
// start read sequence
Wire.beginTransmission(address);
Wire.write((byte) 0x00);
Wire.endTransmission();
Wire.beginTransmission(address);
Wire.requestFrom(address, (int)3);
if (Wire.available() >= 3)
{
ret = Wire.read() * (unsigned long)65536 + Wire.read() * (unsigned long)256 + Wire.read();
}
else {
ret = -1;
}
Wire.endTransmission();
return ret;
}
void initial(uint8_t address)
{
Serial.println();
Serial.println("PROM COEFFICIENTS ivan");
Wire.beginTransmission(address);
Wire.write(0x1E); // reset
Wire.endTransmission();
delay(10);
for (int i=0; i<6 ; i++) {
Wire.beginTransmission(address);
Wire.write(0xA2 + (i * 2));
Wire.endTransmission();
Wire.beginTransmission(address);
Wire.requestFrom(address, (uint8_t) 6);
delay(1);
if(Wire.available())
{
C[i+1] = Wire.read() << 8 | Wire.read();
}
else {
Serial.println("Error reading PROM 1"); // error reading the PROM or communicating with the device
}
Serial.println(C[i+1]);
}
Serial.println();
}