Code:
#include <msp430xG43x.h>
#include "math.h"
//defines
#define PB_2_0 (1 << 0) // Push Button on P2.0
#define PB_2_1 (1 << 1) // Push Button on P2.1
#define d 0x08
#define c 0x04
#define b 0x02
#define a 0x01
#define h 0x80
#define e 0x40
#define g 0x20
#define f 0x10
// variables declaration
static char beats;
int Datain, Dataout, Dataout_pulse, pulseperiod, counter, heartrate;
// Lowpass FIR filter coefficients for 17 taps to filter > 30Hz
static const int coeffslp[9] = {
5225, 5175, 7255, 9453, 11595, 13507, 15016, 15983, 16315 };
// Highpass FIR filter coefficients for 17 taps to filter < 2Hz
static const int coeffshp[9] = {
-763, -1267, -1091, -1867, -1969, -2507, -2619, -2911, 29908 };
// Character generator definition for display
const char char_gen[] = {
a+b+c+d+e+f, // 0 Displays "0"
b+c, // 1 Displays "1"
a+b+d+e+g, // 2 Displays "2"
a+b+c+d+g, // 3 Displays "3"
b+c+f+g, // 4 Displays "4"
a+c+d+f+g, // 5 Displays "5"
a+c+d+e+f+g, // 6 Displays "6"
a+b+c, // 7 Displays "7"
a+b+c+d+e+f+g, // 8 Displays "8"
a+b+c+d+f+g, // 9 Displays "9"
};
// undefines
#undef a
#undef b
#undef c
#undef d
#undef e
#undef f
#undef g
#undef h
// function prototypes
void Init(void); // Initializes device for the application
void ClearLCD(void); // Clears the LCD memory
int filterlp(int); // 17 tap lowpass FIR filter
int filterhp(int); // 17 tap highpass FIR filter
long mul16(register int x, register int y); // 16-bit signed multiplication
int itobcd(int i); // 16-bit hex to bcd conversion
// main function
void main(void)
{ Init (); // Initialize device for the application
while(1)
{LPM0; // Enter LPM0 needed for UART TX completion
Dataout = filterlp(Datain); // Lowpass FIR filter for filtering out 60Hz
Dataout_pulse = filterhp(Dataout)-128; // Highpass FIR filter to filter muscle artifacts
Dataout = Dataout >> 6; // Scale Dataout to use scope program
if(Dataout>255) // Set boundary 255 max
Dataout=255; //
if(Dataout<0) // Set boundary 0 min
Dataout=0; //
// DAC12_0DAT = Dataout; // For scope display
TXBUF0 = Dataout; // Transmit via UART0 for Scope display
counter++; // Debounce counter
pulseperiod++; // Pulse period counter
if (Dataout_pulse > 48) // Check if above threshold
{ LCDM10 |= 0x0f; // Heart beat detected enable "^" on LCD
counter = 0;} // Reset debounce counter
if (counter == 128) // Allow 128 sample debounce time
{LCDM10 = 0x00; // Disable "^" on LCD for blinking effect
beats++;
if (beats == 3)
{beats = 0;
// heartrate = itobcd(30720/pulseperiod); // Calculate beat to beat heart rate per min
heartrate = itobcd(92160/pulseperiod); // Calculate 3 beat average heart rate per min
pulseperiod = 0; // Reset pulse period for next measurement
LCDMEM[0] = char_gen[heartrate & 0x0f]; // Display current heart rate units
LCDMEM[1] = char_gen[(heartrate & 0xf0) >> 4]; // tens
LCDMEM[2] = char_gen[(heartrate & 0xf00) >> 8];}} // hundreds
}
}//main
// Initialization function
void Init( void )
{ FLL_CTL0 |= XCAP18PF; // Set load capacitance for xtal
WDTCTL = WDTPW | WDTHOLD; // Disable the Watchdog
while ( LFOF & FLL_CTL0); // wait for watch crystal to stabilize
SCFQCTL = 63; // 32 x 32768 x 2 = 2.097152MHz
BTCTL = BT_fLCD_DIV128; // Set LCD frame freq = ACLK/128
// Initialize and enable LCD peripheral
ClearLCD(); // Clear LCD memory
LCDCTL = LCDSG0_3 + LCD4MUX + LCDON ; // 4mux LCD, segs0-23 enabled
// Initialize and enable GPIO ports
P1OUT = 0x00 + BIT3; // Clear P1OUT register, INA turned ON
P1DIR = 0x3f; // Unused pins as outputs, Comparator pins as inputs
P2OUT = 0x00; // Clear P2OUT register
P2DIR = 0xff; // Unused pins as outputs
P2DIR = ~(PB_2_0+PB_2_1); // P2.0 and P2.1 push buttons
P2IES = 0x00; // Interrupt edge low to high transition
P2IFG = 0x00; // Clear pending P2 interrupts
P2IE = PB_2_0 | PB_2_1; // Enable intterupts for push buttons
P3OUT = 0x00; // Clear P3OUT register
P3DIR = 0xff; // Unused pins as outputs
P4OUT = 0x00; // Clear P4OUT register
P4DIR = 0xff; // Unused pins as outputs
P5OUT = 0x00; // Clear P5OUT register
P5DIR = 0xff; // Unused pins as outputs
P5SEL = 0xfc; // Set Rxx and COM pins for LCD
P6OUT = 0x00; // Clear P6OUT register
P6SEL = 0xff; // P6 = Analog
// Initialize and enable UART
P2SEL|=BIT4; // P2.4 = TXD
UCTL0 |= SWRST; // UART SWRST = 1
ME1 |= UTXE0; // Enable UART0 TXD
UCTL0 |= CHAR; // 8-bit char, SWRST=1
UTCTL0 |= SSEL1; // UCLK = SMCLK
UBR00 = 18; // 115200 from 2.097152MHz
UBR10 = 0;
UMCTL0 = 0x2c; // Modulation = 0.2044
UCTL0 &= ~SWRST; // UART SWRST = 0, enable UART
// Initialize and enable ADC12
ADC12CTL0 = ADC12ON + SHT0_4 + REFON + REF2_5V; // ADC12 ON, Reference = 2.5V for DAC0
ADC12CTL1 = SHP + SHS_1 + CONSEQ_2; // Use sampling timer, TA1 trigger
ADC12MCTL0 = INCH_1 + SREF_1; // Vref, channel = 1 = OA0 Out
ADC12IE = BIT0; // Enable interrupt for ADC12 MEM0
ADC12CTL0 |= ENC; // Enable conversions
// Initialize and enable Timer_A
TACTL = TASSEL0 + MC_1 + TACLR; // ACLK, Clear TAR, Up Mode
TACCTL1 = OUTMOD_2; // Set / Reset
TACCR0 = 63; // 512 samples per second
TACCR1 = 15; //
// Initialize and enable DAC12x
DAC12_0CTL = DAC12OPS + DAC12CALON + DAC12IR + DAC12AMP_2 + DAC12ENC;// DAC0 enable
DAC12_1CTL = DAC12CALON + DAC12IR + DAC12AMP_2 + DAC12ENC; // DAC1 enable
DAC12_1DAT = 0x099A; // Offset level = 1.5V for op amp bias
// Initialize and enable opamps
OA0CTL0 = OAP_1 + OAPM_1 + OAADC1; // OA0 enable power mode 1, OA0- = P6.0, 0A0+ = P6.2, OA0O = P6.1
OA0CTL1 = OARRIP; // General purpose mode, no Rail-to-Rail inputs
OA1CTL0 = OAP_3 + OAPM_1 + OAADC1; // OA1 enable power mode 1, OA1- = P6.4, OA1+ = DAC1, OA1O = P6.3
OA1CTL1 = OARRIP; // General purpose mode, no Rail-to-Rail inputs
OA2CTL0 = OAP_3 + OAPM_1 + OAADC1; // OA2 enable power mode 1, OA2+ = DAC1, OA2O = P6.5, Select inputs, power mode
OA2CTL1 = OAFC_1 + OARRIP; // Unit gain Mode, no Rail-to-Rail inputs
_EINT(); // Enable global Interrupts
} //init
void ClearLCD(void)
{ int i; //
for( i = 0; i < 16; i++){ // Clear LCDMEM
LCDMEM[i] = 0; //
}
}//clear LCD
int itobcd(int i) // Convert hex word to BCD.
{ int bcd = 0; //
char j = 0; //
while (i > 9) //
{bcd |= ((i % 10) << j); //
i /= 10; //
j += 4;} //
return (bcd | (i << j)); // Return converted value
}// itobcd(i)
int filterlp(int sample) // Lowpass FIR filter for EKG
{ static int buflp[32]; // Reserve 32 loactions for circular buffering
static int offsetlp = 0;
long z;
int i;
buflp[offsetlp] = sample;
z = mul16(coeffslp[8], buflp[(offsetlp - 8) & 0x1F]);
for (i = 0; i < 8; i++)
z += mul16(coeffslp[i], buflp[(offsetlp - i) & 0x1F] + buflp[(offsetlp - 16 + i) & 0x1F]);
offsetlp = (offsetlp + 1) & 0x1F;
return z >> 15; // Return filter output
}// int filter
int filterhp(int samplehp) // Highpass FIR filter for hear rate
{ static int bufhp[32]; // Reserve 32 loactions for circular buffering
static int offsethp = 0;
long z;
int i;
bufhp[offsethp] = samplehp;
z = mul16(coeffshp[8], bufhp[(offsethp - 8) & 0x1F]);
for (i = 0; i < 8; i++)
z += mul16(coeffshp[i], bufhp[(offsethp - i) & 0x1F] + bufhp[(offsethp - 16 + i) & 0x1F]);
offsethp = (offsethp + 1) & 0x1F;
return z >> 15; // Return filter output
}// int filterhp
#pragma vector = PORT2_VECTOR
__interrupt void Port2ISR (void)
{ P2IFG = 0;
}//Push buttons unused
#pragma vector = ADC_VECTOR // ADC12 ISR
__interrupt void ADC12ISR (void)
{ Datain = ADC12MEM0; // Store converted value in Datain
LPM0_EXIT; // Exit LPM0 on return
}// ADC12ISR
