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//***************************************************************************** // MSP430FG439-Heart Rate Monitor Demo // // Description; Uses one Instrumentation Amplifier INA321 and the three // internal opamps of the MSP430FG439 // // LSD ZHANGCHONG // MAY 2006 // Built with IAR Embedded Workbench Version: 3.20A //*****************************************************************************
//***************************************************************************** #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 c 0x01 // LSD 048 LCD SEGMENT DISPLAY #define f 0x02 #define e 0x04 #define h 0x08 #define a 0x10 #define b 0x20 #define g 0x40 #define d 0x80
// 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 LCDMEM[1]=0X61; // LSD048 LCD MARK DISP LCDMEM[2]=0X46; // LSD048 LCD MARK DISP counter = 0;} // Reset debounce counter if (counter == 128) // Allow 128 sample debounce time {//LCDM10 = 0x00; // Disable "^" on LCD for blinking effect LCDMEM[1]=0X00; // LSD048 LCD MARK DISP LCDMEM[2]=0X00; // LSD048 LCD MARK DISP 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[6] = char_gen[heartrate & 0x0f]; // Display current heart rate unitsn 0 LCDMEM[5] = char_gen[(heartrate & 0xf0) >> 4]; // tens 1 LCDMEM[4] = char_gen[(heartrate & 0xf00) >> 8];}} // hundreds 2 } }//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 //DAC12_1DAT = 0x0000; // 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
