BME280_F.c

#include <msp430.h> 
#include <stdio.h>
#include <stdint.h>
#include "BME280.h"

/*
 Read and display temperature, relative humidity, and pressure with BME280 sensor on F5529 Launchpad.  
 Sensor polled in forced mode using the SPI interface. Internal trimming parameters must be
 read from device to perform conversion of raw data.  Data displayed on terminal program. 
 Set serial port for 9600 baud, 8-bits, 1 stop, no parity, no flow control. UART interface is 
 on TXD (P3.3) and RXD (P3.4); UART polling with no RX interrupt. Green LED on P4.7 
 illuminates during data transmission. SPI lines are on P3.0 (MOSI), P3.1 (MISO), P3.2 (CLK), 
 and P1.5 (CS) of UCB0 module. SPI clock 1 MHz.The CS line must be configured consistently in
 the BME280.h file. Main loop runs with timed interrupt from LPM3 and VLO clock. IDE with 
 CCS 6.1.3 and nofloat printf support. Launchpad pins:

	P3.0  MOSI  SPI
	P3.1  MISO  SPI
	P3.2  CLK  SPI
	P3.3  TXD  UART
	P3.4  RXD  UART
	P1.5  CS  SPI
 */

# define PERIOD 10000 //Samping period. 10000 count is approximately 1 second; maximum is 65535

void SetTimer(void);
void SetVLO(void);
void SetPins(void);
void SetUART(void);
void SetSPI(void);

//Variables for UART terminal display
char str[80];
volatile uint8_t i,count;
volatile int32_t CorT;
volatile uint32_t CorH, CorP;

void main(void) {

    WDTCTL = WDTPW | WDTHOLD;	// Stop watchdog timer

    SetPins();
    SetVLO();
    SetTimer();
    SetUART();
    SetSPI();

    _BIS_SR(GIE); //Enable global interrupts.

    if(ReadTHid()); //Check for presence of sensor; read its ID code
    else  //Trap CPU and turn on red LED if not found
    {
    	P1OUT |= BIT0;
    	while(1){}
    }

    //Get the trimming parameters from sensor for raw data conversion
    GetCompData();

    while(1)
    {
    	 TA0CCR0 = PERIOD; // Polling period
    	 LPM3;		//Wait in low power mode
    	 P4OUT |= BIT7; //Timeout. Turn on green LED on Launchpad
    	 //Burst read on SPI to get 3 press data bytes, 3 temp bytes and 2 humidity bytes
    	 ReadTHsensor();
    	 //Apply cal factors to raw data
    	 CorT = CalcTemp(); //Corrected temperature
    	 CorH = CalcHumid(); //Corrected humidity
    	 CorP = CalcPress(); //Corrected pressure
    	 //Send data to serial port for display
    	 sprintf(str,"%s %lu.%.2lu%s %lu.%.2lu%s %lu.%.2lu%s", "Temperature:", CorT/100, CorT%100,"C Rel Humidity:",
    			 CorH/1000, CorH%100,"% Pressure:",CorP/100, CorP%100," hPa\r\n\n");
    	 count = sizeof str;
    	 for (i=0; i < count; i++)
    	 {
    		 while (!(UCA0IFG & UCTXIFG)); // USCI_A0 TX buffer ready?
    		 UCA0TXBUF = str[i]; //Send data 1 byte at a time
    	 }
    	 P4OUT &= ~BIT7; //Turn off LED
    }
}

#pragma vector=TIMER0_A0_VECTOR 
 __interrupt void timerfoo (void) 
 {
	LPM3_EXIT;
 }

 void SetPins(void)
  {
	/* Port 1
	P1.0 Red LED
 	P1.5 TH Select.  Pull this CSB line low to enable BME280 communication
 	CS_TH must also be defined in BME280.h
	*/
 	P1DIR |= BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;
 	P1OUT &= ~BIT0; //LED off

 	/* Port 2
 	P2.1  Button on Launchpad
 	*/
 	P2DIR |= BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;

 	/* Port 3 */
 	P3SEL = BIT0 + BIT1 + BIT2 + BIT3 + BIT4; //SPI + UART lines
 	P3DIR |= BIT5 + BIT6 + BIT7; //Unused lines

 	/* Port 4
 	P4.0--4.6 unused
 	P4.7 Green LED
 	*/
 	P4DIR |= BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;
 	P4OUT &= ~BIT7;

 	/* Port 5
 	P5.0 Unused
 	P5.1 Unused
 	P5.2--P5.5 grounded or open as per spec sheet
 	*/
 	P5DIR |= BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;

 	/* Port 6
 	P6.0--6.7 unused
 	*/
 	P6DIR |= BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;
  }

 void SetVLO(void)
    { //Default frequency ~ 10 kHz
	UCSCTL4 |= SELA_1;  //Set ACLK to VLO
    }

 void SetTimer(void)
     {
 	TA0CCTL0 |= CCIE;  //Enable timer interrupt
 	TA0CTL = TASSEL_1 | MC_1;  //Set Timer A to ACLK; MC_1 to count up to TA0CCR0.
     }

 void SetUART(void)
  {
 	 UCA0CTL1 |= UCSWRST;                      // Reset to configure
 	 UCA0CTL1 |= UCSSEL_2;                     // SMCLK
 	 UCA0BR0 = 6;                              // Prescalers for 9600 baud
 	 UCA0BR1 = 0;                              
 	 UCA0MCTL = UCBRS_0 + UCBRF_13 + UCOS16;   // Modln UCBRSx=0, UCBRFx=0,
 	 UCA0CTL1 &= ~UCSWRST;                     // Initialize
  }

 void SetSPI(void)
   {
  	 // Configure the USCI module: 3-pin SPI
	 UCB0CTL1 |= UCSSEL_2 + UCSWRST;  //Select SMCLK; should be in reset state at PUC but set anyway
	 UCB0CTL0 |= UCMST + UCSYNC + UCMSB + UCCKPH; //Set as master, synchronous, MSB first, clock phase adjust
  	 //UCB0BR0 |= 0x02; //Divide SMCLK by 2 to clock at 500 kHz
	 UCB0BR0 |= 0x01; //1 MHz SPI clock
	 UCB0BR1 |= 0x00;
   }