MPL115A1 pressure sensor arduino uno

Hello guys, I bring you this code for the sensor MPL115A1. I don’t do it but it works, so don’t make me questions about how it works because I don’t have many ideas. Just enjoy it!!! The only thing that I know is if the sensor isn’t good soldier it doesn’t work. I used arduino 1. The way to connect is:
3.3 V
pin 9 to SHDN
pin 10 to CS
pin 11 to Din (MOSI)
pin 12 to Dout (MISO)
pin 13 to SCLK

#include <SPI.h>
#include <Wire.h>
#define NWS_BARO 30.04

// Pin definitions
#define MPL115A1_ENABLE_PIN 9
#define MPL115A1_SELECT_PIN 10

// Masks for MPL115A1 SPI i/o
#define MPL115A1_READ_MASK 0x80
#define MPL115A1_WRITE_MASK 0x7F

// MPL115A1 register address map
#define PRESH 0x00 // 80
#define PRESL 0x02 // 82
#define TEMPH 0x04 // 84
#define TEMPL 0x06 // 86

#define A0MSB 0x08 // 88
#define A0LSB 0x0A // 8A
#define B1MSB 0x0C // 8C
#define B1LSB 0x0E // 8E
#define B2MSB 0x10 // 90
#define B2LSB 0x12 // 92
#define C12MSB 0x14 // 94
#define C12LSB 0x16 // 96
#define C11MSB 0x18 // 98
#define C11LSB 0x1A // 9A
#define C22MSB 0x1C // 9C
#define C22LSB 0x1E // 9E

// Macro di conversione
#define FT_TO_M(x) ((long)((x)(0.3048)))
#define KPA_TO_INHG(x) ((x)
(0.295333727))
#define KPA_TO_ATM(x) ((x)(0.00986923267))
#define KPA_TO_MMHG(x) ((x)
(7.50061683))
#define KPA_TO_PSIA(x) ((x)(0.145037738))
#define KPA_TO_KGCM2(x) ((x)
(0.0102))
#define INHG_TO_PSIA(x) ((x)(0.49109778))
#define DEGC_TO_DEGF(x) ((x)
(9.0/5.0)+32)

//void writeRegister(unsigned char r, unsigned char v);
//void writeInteger(unsigned char r, unsigned int v);
//unsigned char readRegister(unsigned char r);
//void readRegisters(unsigned char r, unsigned int numberOfBytes, unsigned char buffer);
//unsigned int readInteger(unsigned char r);
//unsigned long readLong(unsigned char r);

//byte READ = 0b11111100; // SCP1000’s read command
//byte WRITE = 0b00000010; // SCP1000’s write command

void setup(void) {
Serial.begin(9600);
//pinMode(P_SENSOR, INPUT);

// Interfaccia SPI
SPI.begin();

// Inializzazione dei pin di chip select ed enable
pinMode(MPL115A1_SELECT_PIN, OUTPUT);
pinMode(MPL115A1_ENABLE_PIN, OUTPUT);

digitalWrite(MPL115A1_ENABLE_PIN, LOW);
digitalWrite(MPL115A1_SELECT_PIN, HIGH);

// spam welcome banner
Serial.print("\n************************************************************************************\n");
Serial.print("* La presion inicial que se utiliza es: “);
Serial.print(NWS_BARO, 2);
Serial.print(” en inHg \n");
//Serial.print("
Visit http://www.weather.gov for your current local value. \n");
Serial.print("
***********************************************************************************\n");
}
void loop() {

float pressure_pKa = 0;
float tempf = 0;
long altitude_ft = 0;
float uiTadc = 0;

digitalWrite(MPL115A1_ENABLE_PIN, HIGH);
delay(20); // give the chip a few ms to wake up

pressure_pKa = calculatePressurekPa();
tempf = calculateTemperatureC();
altitude_ft = calculateAltitudeFt(pressure_pKa);

digitalWrite(MPL115A1_ENABLE_PIN, LOW);

Serial.print(FT_TO_M(altitude_ft));
Serial.print(" m | “);
Serial.print(KPA_TO_MMHG(pressure_pKa));
Serial.print(” mm Hg | “);
Serial.print(pressure_pKa);
Serial.print(” kPa | “);
Serial.print(tempf);
Serial.print(” C | ");

delay(500);
}

long calculateAltitudeFt(float pressure_kPa) {

float delta;
long altitude_ft;

delta = KPA_TO_PSIA(pressure_kPa) / INHG_TO_PSIA( NWS_BARO );
altitude_ft = (1 - pow(delta, (1 / 5.25587611))) / 0.0000068756;

return altitude_ft;
}

float calculateTemperatureC() {
unsigned int uiTadc;
unsigned char uiTH, uiTL;
unsigned int temperature_counts = 0;

float tempf = 0;

writeRegister(0x22, 0x00); // Start temperature conversion
delay(2); // Max wait time is 0.7ms, typ 0.6ms

// Read pressure
uiTH = readRegister(TEMPH);
uiTL = readRegister(TEMPL);

uiTadc = (unsigned int) uiTH << 8;
uiTadc += (unsigned int) uiTL & 0x00FF;

// Temperature is a 10bit value
uiTadc = uiTadc >> 6;

tempf = 25 + (uiTadc - 472) / -5.35;
// -5.35 counts per °C, 472 counts is 25°C

return tempf;
}

float calculatePressurekPa() {

// See Freescale document AN3785 for detailed explanation
// of this implementation.

signed char sia0MSB, sia0LSB;
signed char sib1MSB, sib1LSB;
signed char sib2MSB, sib2LSB;
signed char sic12MSB, sic12LSB;
signed char sic11MSB, sic11LSB;
signed char sic22MSB, sic22LSB;
signed int sia0, sib1, sib2, sic12, sic11, sic22, siPcomp;
float decPcomp;
signed long lt1, lt2, lt3, si_c11x1, si_a11, si_c12x2;
signed long si_a1, si_c22x2, si_a2, si_a1x1, si_y1, si_a2x2;
unsigned int uiPadc, uiTadc;
unsigned char uiPH, uiPL, uiTH, uiTL;

writeRegister(0x24, 0x00); // Start Both Conversions
delay(2); // Max wait time is 1ms, typ 0.8ms

// Read pressure
uiPH = readRegister(PRESH);
uiPL = readRegister(PRESL);
uiTH = readRegister(TEMPH);
uiTL = readRegister(TEMPL);

uiPadc = (unsigned int) uiPH << 8;
uiPadc += (unsigned int) uiPL & 0x00FF;
uiTadc = (unsigned int) uiTH << 8;
uiTadc += (unsigned int) uiTL & 0x00FF;

// Placing Coefficients into 16-bit Variables
// a0
sia0MSB = readRegister(A0MSB);
sia0LSB = readRegister(A0LSB);
sia0 = (signed int) sia0MSB << 8;
sia0 += (signed int) sia0LSB & 0x00FF;

// b1
sib1MSB = readRegister(B1MSB);
sib1LSB = readRegister(B1LSB);
sib1 = (signed int) sib1MSB << 8;
sib1 += (signed int) sib1LSB & 0x00FF;

// b2
sib2MSB = readRegister(B2MSB);
sib2LSB = readRegister(B2LSB);
sib2 = (signed int) sib2MSB << 8;
sib2 += (signed int) sib2LSB & 0x00FF;

// c12
sic12MSB = readRegister(C12MSB);
sic12LSB = readRegister(C12LSB);
sic12 = (signed int) sic12MSB << 8;
sic12 += (signed int) sic12LSB & 0x00FF;

// c11
sic11MSB = readRegister(C11MSB);
sic11LSB = readRegister(C11LSB);
sic11 = (signed int) sic11MSB << 8;
sic11 += (signed int) sic11LSB & 0x00FF;

// c22
sic22MSB = readRegister(C22MSB);
sic22LSB = readRegister(C22LSB);
sic22 = (signed int) sic22MSB << 8;
sic22 += (signed int) sic22LSB & 0x00FF;

// Coefficient 9 equation compensation
uiPadc = uiPadc >> 6;
uiTadc = uiTadc >> 6;

// Step 1 c11x1 = c11 * Padc
lt1 = (signed long) sic11;
lt2 = (signed long) uiPadc;
lt3 = lt1*lt2;
si_c11x1 = (signed long) lt3;

// Step 2 a11 = b1 + c11x1
lt1 = ((signed long)sib1)<<14;
lt2 = (signed long) si_c11x1;
lt3 = lt1 + lt2;
si_a11 = (signed long)(lt3>>14);

// Step 3 c12x2 = c12 * Tadc
lt1 = (signed long) sic12;
lt2 = (signed long) uiTadc;
lt3 = lt1*lt2;
si_c12x2 = (signed long)lt3;

// Step 4 a1 = a11 + c12x2
lt1 = ((signed long)si_a11<<11);
lt2 = (signed long)si_c12x2;
lt3 = lt1 + lt2;
si_a1 = (signed long) lt3>>11;

// Step 5 c22x2 = c22*Tadc
lt1 = (signed long)sic22;
lt2 = (signed long)uiTadc;
lt3 = lt1 * lt2;
si_c22x2 = (signed long)(lt3);

// Step 6 a2 = b2 + c22x2
lt1 = ((signed long)sib2<<15);
lt2 = ((signed long)si_c22x2>1);
lt3 = lt1+lt2;
si_a2 = ((signed long)lt3>>16);

// Step 7 a1x1 = a1 * Padc
lt1 = (signed long)si_a1;
lt2 = (signed long)uiPadc;
lt3 = lt1*lt2;
si_a1x1 = (signed long)(lt3);

// Step 8 y1 = a0 + a1x1
lt1 = ((signed long)sia0<<10);
lt2 = (signed long)si_a1x1;
lt3 = lt1+lt2;
si_y1 = ((signed long)lt3>>10);

// Step 9 a2x2 = a2 * Tadc
lt1 = (signed long)si_a2;
lt2 = (signed long)uiTadc;
lt3 = lt1*lt2;
si_a2x2 = (signed long)(lt3);

// Step 10 pComp = y1 + a2x2
lt1 = ((signed long)si_y1<<10);
lt2 = (signed long)si_a2x2;
lt3 = lt1+lt2;

// Fixed point result with rounding
//siPcomp = ((signed int)lt3>>13);
siPcomp = lt3/8192;

return decPcomp;
}

unsigned int readRegister(byte thisRegister) {

byte result = 0;

// select the MPL115A1
digitalWrite(MPL115A1_SELECT_PIN, LOW);

// send the request
SPI.transfer(thisRegister | MPL115A1_READ_MASK);
result = SPI.transfer(0x00);

// deselect the MPL115A1
digitalWrite(MPL115A1_SELECT_PIN, HIGH);

return result;
}

void writeRegister(byte thisRegister, byte thisValue) {

// select the MPL115A1
digitalWrite(MPL115A1_SELECT_PIN, LOW);

// send the request
SPI.transfer(thisRegister & MPL115A1_WRITE_MASK);
SPI.transfer(thisValue);

// deselect the MPL115A1
digitalWrite(MPL115A1_SELECT_PIN, HIGH);
}