#include "msp430g2553.h"

/*

* EC450 Final Project

* Leveling device

* Fall 2013

*

*/

#define LED_center 0x01 // on or off, level is flat indicator.

#define LED_Xaxis 0x02 // x-axis/horizontal LED array (local axis) (Timer 1 output) P2 output!

#define LED_Yaxis 0x04 // y-axis/vertical LED array (local axis) (Timer 0 output) P1 output!

#define BUTTON_BIT 0x08 // button bit

#define CS 0x10 //UCB0STE P1sel + p1sel2 both 1

#define SCLK 0x20 //UCB0CLK 1 + 1

#define SDO 0x40 //UCB0SOMI 1 + 1

#define SDI 0x80 //UCB0SIMO 1 + 1

#define DATAX0 0x32 //data address of accelerometer

#define DATAX1 0x33

#define DATAY0 0x34

#define DATAY1 0x35

#define DATAZ0 0x36

#define DATAZ1 0x37

#define wait_tm while ((UCB0STAT & UCBUSY));

#define wait_btw __delay_cycles(10);

volatile char val, xval0, xval1, yval0, yval1, zval0, zval1; //accelerometer intermediate variables

volatile char count; // counting variable to wait for a time for the device being level before turning on the LED.

const char scale = 200; // scaling factor to make brightness of LED's vary more over a small range

const int threshold = 0x1000; // threshold factor for how off from "flat" it can be while allowing the center LED to turn on

/* declarations of functions defined later */

void init_adc(void); // adc setup

void init_timer(void); // timer setup

void init_button(void); // button setup

void init_SPI();

void init_accel(void);

char read_byte(char addr);

void write_byte(char addr, char b);

/* global variables */

volatile unsigned int xaxis_calibrate; // calibration of the x-axis (used as a centering offset)

volatile unsigned int yaxis_calibrate; // calibration of the y-axis (used as a centering offset)

// note that "center" or 50-50 or level, is the value 32756.

// the 3 axis stored/received from the accelerometer... or should it be signed for our reference?

volatile signed int x_axis;

volatile signed int y_axis;

volatile signed int z_axis;

// main function

void main(){

WDTCTL = WDTPW + WDTTMSEL+ WDTCNTCL + 0; // setup using the watchdog timer, using the 8MHz clock, 00 us /32768

BCSCTL1 = CALBC1_8MHZ; // 8Mhz calibration for clock

DCOCTL = CALDCO_8MHZ;

init_timer(); // initialize timer

init_button(); // initialize the button

// clear/initialize the global variables

xaxis_calibrate=0;

yaxis_calibrate=0;

x_axis=0;

y_axis=0;

z_axis=1;

count= 100;

P1REN = BUTTON_BIT;

P1DIR |= LED_center; //(BUTTON_BIT+LED_Xaxis+LED_Yaxis+LED_center);

P1OUT &= ~LED_center;

init_SPI();

init_accel();

IE1 |= WDTIE; //enable the WDT interrupt

_bis_SR_register(GIE+LPM0_bits); // enable general interrupts and power down CPU

}

// Sound Production System

void init_timer(){ // initialization and start of timer

// setup of timer 1 & 0 overall

TA0CTL |= TACLR; // reset clock

TA0CTL = TASSEL_2+ID_0+MC_2; // clock source = SMCLK (TASSEL_2)

// clock divider=1 (ID_3 is /8)

// continuous mode (MC_2, MC_1 is up mode)

// timer A interrupt off (turn on, add TAIE interrupt enable)

TA1CTL |= TACLR; // reset clock

TA1CTL = TASSEL_2+ID_0+MC_2;

// setup the individual channels on Timer1

TA1CCTL1=OUTMOD_7; // second channel settings

P2SEL|= LED_Xaxis; // connect timer output to pin // connect other timer output to pin

P2DIR|= LED_Xaxis;

// setup the individual channels on Timer0

TA0CCTL1=OUTMOD_7; // second channel settings (channel 2 is not accessible)

P1SEL|= LED_Yaxis; // connect timer output to pin // connect other timer output to pin

P1DIR|= LED_Yaxis;

// registers set behavior for all of timer 0.

TA0CCR0 = 0xFFF0; // in up mode TAR=0... TACCRO-1

TA0CCR1 = 0x0FFF;

// registers set behavior for all of timer 1.

TA1CCR0 = 0xFFF0;

TA1CCR1 = 0x0FFF;

}

// Button input System

void init_button(){

P1OUT |= BUTTON_BIT; // pullup

P1REN |= BUTTON_BIT; // enable resistor

//P1IES &= ~BUTTON_BIT; // set for 1->0 transition

P1IFG &= ~(BUTTON_BIT);// clear interrupt flag

P1IE |= BUTTON_BIT; // enable interrupt

}

// button handler, for calibration

void interrupt button_handler(){

if (P1IFG & BUTTON_BIT){

// reset flag

P1IFG &= ~BUTTON_BIT;

// here we set the calibration values

xaxis_calibrate = TA1CCR1-32768+xaxis_calibrate;

yaxis_calibrate = TA0CCR1-32768+yaxis_calibrate;

}

}

ISR_VECTOR(button_handler, ".int02")

// communication setup, SPI

void init_SPI(void){

UCB0CTL1 = UCSWRST; // reset USCI logic

UCB0CTL1 |= UCSSEL_2; // SMCLK is clock source

UCB0BR0= 32; // USCI clock divisor low -- from parameters file

UCB0BR1=0; // USCI clock divisor high

UCB0CTL0 = UCCKPL

+UCMSB // MSB first

+UCMST // Master

+UCMODE_0 // 3 pin SPI

+UCSYNC;// sync mode (needed for SPI)

// configure port to connect to UCB0 (not the MISO pin though

P1SEL |= SCLK + SDO + SDI;

P1SEL2 |= SCLK + SDO + SDI;

P1DIR |= CS;

P1OUT |= CS;

UCB0CTL1 &= ~(UCSWRST); // exit reset state for USCI

}

void init_accel(void){

val = read_byte(0x00); //read dev id

write_byte(0x2D, 0x08); // set to measurement mode

write_byte(0x31, 0x00); // set data format - +/- 2g, right justified with SE

}

void write_byte(char addr, char b) {

P1OUT &= ~CS;

while((IFG2&UCB0TXIFG)==0); //wait for TX flag to be set

UCB0TXBUF=addr; //put address into TX buffer to write it

wait_tm;

UCB0TXBUF=b; //write data

wait_tm;

P1OUT |= CS;

}

char read_byte(char addr) {

P1OUT &= ~CS;

while((IFG2&UCB0TXIFG)==0); //wait for TX flag to be set

UCB0TXBUF=addr+0x80; //put address into TX buffer to write it

wait_tm;

UCB0TXBUF=0xFF; //dummy data to get read value

wait_tm;

P1OUT |= CS;

return UCB0RXBUF; //return read value

}

interrupt void WDT_interval_handler(){

// send/get the data from the accelerometer

xval0 = read_byte(DATAX0);

xval1 = read_byte(DATAX1);

x_axis = xval0 + (xval1<<8);

yval0 = read_byte(DATAY0);

yval1 = read_byte(DATAY1);

y_axis = yval0 + (yval1<<8);

zval0 = read_byte(DATAZ0);

zval1 = read_byte(DATAZ1);

z_axis = zval0 + (zval1<<8);

// state machine for the accelerometer

if (z_axis > 170 || z_axis < -170){

// it is flat on the table, set the x and y values to the timers

TA1CCR1 = (x_axis*scale + 32768);

TA0CCR1 = (-y_axis*scale + 32768);

}

else if (x_axis > 170 || x_axis < -170){

// it is on its side

TA1CCR1 = (z_axis*scale + 32768);

TA0CCR1 = (-y_axis*scale + 32768);

}

else if (y_axis > 170 || y_axis < -170){

// on its other side

TA1CCR1 = (x_axis*scale + 32768);

TA0CCR1 = (-z_axis*scale + 32768);

}

else{

// other in-between cases, have a neutral output

TA1CCR1 = 0x8000;

TA0CCR1 = 0x8000;

}

// calibration, affect the currently selected axis in the timers

TA1CCR1 -= xaxis_calibrate;

TA0CCR1 -= yaxis_calibrate;

// logic for turning on the center LED

if ( (TA1CCR1 < 32768+threshold) && (TA1CCR1 > 32768-threshold) && (TA0CCR1 < 32768+threshold) && (TA0CCR1 > 32768-threshold)){

if (count--==0){

// LED on

P1OUT|=LED_center;

count = 100;

}

}

else{

//LED off

count = 100;

P1OUT&= ~LED_center;

}

}

ISR_VECTOR(WDT_interval_handler, ".int10") //declare watchdog interrupt