Commit e1ba91a

#include <SPI.h>

const int PRESSURE = 0x1F; //3 most significant bits of pressure

const int PRESSURE_LSB = 0x20; //16 least significant bits of pressure

const int TEMPERATURE = 0x21; //16 bit temperature reading

const int dataReadyPin = 6;

const int chipSelectPin = 7;

void setup() {

Serial.begin(9600);

// initalize the data ready and chip select pins:

pinMode(dataReadyPin, INPUT);

pinMode(chipSelectPin, OUTPUT);

// start the SPI library:

SPI.begin();

//Configure SCP1000 for low noise configuration:

writeRegister(0x02, 0x2D);

writeRegister(0x01, 0x03);

writeRegister(0x03, 0x02);

// give the sensor time to set up:

delay(100);

}

void loop() {

//Select High Resolution Mode

writeRegister(0x03, 0x0A);

// don't do anything until the data ready pin is high:

if (digitalRead(dataReadyPin) == HIGH) {

//Read the temperature data

int tempData = readRegister(0x21, 2);

// convert the temperature to celsius and display it:

float realTemp = (float)tempData / 20.0;

Serial.print("Temp[C]=");

Serial.print(realTemp);

//Read the pressure data highest 3 bits:

byte pressure_data_high = readRegister(0x1F, 1);

pressure_data_high &= 0b00000111; //you only needs bits 2 to 0

//Read the pressure data lower 16 bits:

unsigned int pressure_data_low = readRegister(0x20, 2);

//combine the two parts into one 19-bit number:

long pressure = ((pressure_data_high << 16) | pressure_data_low)/4;

// display the temperature:

Serial.println("\tPressure [Pa]=" + String(pressure));

}

}

void writeRegister(byte registerName, byte registerValue) {

// SCP1000 expects the reguster name in the upper 6 bits

// of the byte:

registerName <<= 2;

// command goes in the lower two bits:

registerName |= 0b00000010; //Write command

// take the chip select low to select the device:

digitalWrite(chipSelectPin, LOW);

SPI.send(registerName); //Send register location

SPI.send(registerValue); //Send value to record into register

// take the chip select high to de-select:

digitalWrite(chipSelectPin, HIGH); //Select SPI device

}

unsigned int readRegister(byte registerName, int numBytes) {

byte inByte = 0; // incoming from the SPI read

unsigned int result = 0; // result to return

// SCP1000 expects the reguster name in the upper 6 bits

// of the byte:

registerName <<= 2;

// command goes in the lower two bits:

registerName &= 0b11111100; //Read command

// take the chip select low to select the device:

digitalWrite(chipSelectPin, LOW);

// send the device the register you want to read:

int command = SPI.send(registerName);

// send a value of 0 to read the forst byte returned:

inByte = SPI.send(0x00);

// if there's more than one byte returned,

// shift the first byte then get the second byte:

switch(numBytes) {

case 1:

result = inByte;

break;

case 2:

result = inByte << 8;

inByte = SPI.send(0x00);

result = result |inByte;

break;

}

// take the chip select high to de-select:

digitalWrite(chipSelectPin, HIGH);

// return the result:

return(result);

}