/* * File: Breathe-Easy EEG System (eeg.c) * Author: Vasudharini Mannar (vkm22), Namita Kumar (nk437) * Target PIC: PIC32MX250F128B */ //////////////////////////////////// // clock AND protoThreads configure! // You MUST check this file! #include "config.h" // threading library #include "pt_cornell_1_2_1.h" //////////////////////////////////// // graphics libraries #include "tft_master.h" #include "tft_gfx.h" // need for rand function #include #include //////////////////////////////////// /* Main code that runs the Breathe-Easy EEG */ // string buffer char buffer[60]; //FFT Defines #define N_WAVE 512 /* size of FFT 512 */ #define LOG2_N_WAVE 9 /* log2(N_WAVE) 0 */ #define begin { #define end } //Define alpha (calm) and beta (excited) wave bands #define CALM_BEGIN 5*512/(333.3) #define CALM_END 16*512/(333.3) #define EXCITED_BEGIN 17*512/(333.3) #define EXCITED_END 40*512/(333.3) //Debouncing Defines #define NoPush 0 #define MaybePush 1 #define Pushed 2 #define MaybeRelease 3 //Pull Down/Up Resistors for PORT B #define EnablePullDownB(bits) CNPUBCLR=bits; CNPDBSET=bits; #define DisablePullDownB(bits) CNPDBCLR=bits; #define EnablePullUpB(bits) CNPDBCLR=bits; CNPUBSET=bits; #define DisablePullUpB(bits) CNPUBCLR=bits; void FFTfix(int fr[], int fi[], int m); float arr_avg (float arr[], int size); //=== fixed conversion macros ========================================= // for 16.16 fixed point typedef signed int fix ; #define int2fix(a) (((fix)(a))<<16) //Convert char to fix. a is a char #define fix2int(a) ((signed int)((a)>>16)) //Convert fix to int. a is an int #define float2fix(a) ((fix)((a)*65536.0)) //Convert float to fix. a is a float #define fix2float(a) (((float)(a))/65536.0) //Convert fix to float. a is an int //#define multfix(a,b) ((fix)(((( signed long long)(a))*(( signed long long)(b)))>>16)) //multiply two fixed 16.16 #define multfix(a,b) ((fix)(((( signed long)(a))*(( signed long)(b)))>>16)) //multiply two fixed 16.16 // === thread structures ============================================ // thread control structs static struct pt pt_adc, pt_FFT, pt_control; //Mode control int main_control = 0; //Control Variables/Iterators int draw_iter = 0; int x_val=0; int adc_ready=0; int ratio_iter = 0; int switch_ = 0; int PushState = 0; int push_button, prev_push = 0; //ADC variables static int adc_9, adc_fft; short wav_buf[N_WAVE]; float ratio_filter[3]; int timer_adc = 60000; static short shifted; //Ratio Variables float ratio, avg_ratio=0; int num_calm_samples, num_excited_samples = 0; int max_freq = 0; fix calm, excited = 0; float calm_avg, excited_avg = 0; //FFT variables int Sinewave[N_WAVE]; // a table of sines for the FFT int window[N_WAVE]; // a table of window values for the FFT int fr[N_WAVE], fi[N_WAVE]; int max_fr, max_fr_index, abs_fr, abs_fi; // == Timer 3 ISR ===================================================== void __ISR(_TIMER_3_VECTOR, ipl2) Timer3Handler(void) { mT3ClearIntFlag(); // clear the timer interrupt flag //Take FFT measurement adc_fft = ReadADC10(0); // read the result of channel 9 conversion from the idle buffer AcquireADC10(); // not needed if ADC_AUTO_SAMPLING_ON below //Store ADC samples in temp buffer until we get 512 samples for FFT wav_buf[x_val] = adc_fft; x_val++; if (x_val > N_WAVE-1) { x_val = 0; adc_ready = 1; } } /**The following helper function takes the average of an array */ float arr_avg (float arr[], int size) { float sum; int i; for (i=0; i < size; i++) { sum += arr[i]; } return sum/size; } // === PUSHBUTTON CONTROL THREAD ============================================= static PT_THREAD (protothread_control(struct pt *pt)) { PT_BEGIN(pt); while(main_control == 0) { //PT_YIELD_TIME_msec(500); push_button = mPORTBReadBits(BIT_9); //DEBOUNCING CODE switch (PushState) { case NoPush: if (push_button > 0) { PushState=MaybePush; } else PushState=NoPush; break; case MaybePush: if (push_button > 0) { PushState=Pushed; tft_fillScreen(ILI9340_BLACK); main_control = 1; } else PushState=NoPush; break; case Pushed: if (push_button > 0) PushState=Pushed; else PushState=MaybeRelease; break; case MaybeRelease: if (push_button > 0) PushState=Pushed; else PushState=NoPush; break; } prev_push = push_button; } PT_END(pt); } // animation thread // === FFT & DISPLAY Thread ============================================= static PT_THREAD (protothread_FFT(struct pt *pt)) { PT_BEGIN(pt); while(main_control > 0) { // yield time 1 second // variables for magnitude int abs_fr, abs_fi, max_fr, max_fr_index ; switch_ = mPORTBReadBits(BIT_8); if (switch_) { adc_9 = ReadADC10(0); // read the result of channel 9 conversion from the idle buffer AcquireADC10(); // not needed if ADC_AUTO_SAMPLING_ON below draw_iter++; if (draw_iter > 320) draw_iter = 0; shifted = adc_9 >> 2; tft_fillRoundRect(draw_iter+1,0, 1, 180, 1, ILI9340_BLACK);// x,y,w,h,radius,color tft_drawPixel(draw_iter,shifted-140 , ILI9340_CYAN); // print raw ADC, floating voltage, fixed voltage } //Set variables to 0 for next iteration calm = 0; excited = 0; calm_avg = 0; excited_avg = 0; num_calm_samples = 0; num_excited_samples = 0; if (adc_ready) { // compute and display fft int sample_number; for (sample_number=0; sample_number<512; sample_number++){ fr[sample_number] = multfix(wav_buf[sample_number]<<4, window[sample_number]); // 10 bit to fixed pt fraction <<5 for signal gen fi[sample_number] = 0 ; } FFTfix(fr, fi, LOG2_N_WAVE); // get magnitude max_fr = 0 ; // peak magnitude for freq calc max_fr_index = 0 ; fr[1] = 0 ; // dc scatter // compute approx magnitude, then find the peak for (sample_number=2; sample_number<630/2; sample_number++) { abs_fr = abs(fr[sample_number]) ; //>>9 abs_fi = abs(fi[sample_number]) ; // reuse fr to hold magnitude fr[sample_number] = max(abs_fr, abs_fi) + multfix(min(abs_fr,abs_fi), 26214 ); //0.4 is 26214 in 16:16 fixed if (sample_number > CALM_BEGIN && sample_number < CALM_END) { calm += fr[sample_number]; num_calm_samples += 1; } //Sum all bins between 17 Hz and 40 Hz (Alpha Waves) else if (sample_number > EXCITED_BEGIN && sample_number < EXCITED_END) { excited += fr[sample_number]; num_excited_samples += 1; } if (fr[sample_number]>max_fr) { //Determine largest FFT index for max freq max_fr = fr[sample_number]; max_fr_index = sample_number; } if (!switch_) { //FFT DISPLAY CODE tft_fillRoundRect(sample_number+1,0, 1, 200, 1, ILI9340_BLACK);// x,y,w,h,radius,color tft_drawPixel(sample_number, 240-(fr[sample_number]+60), ILI9340_MAGENTA); } } //Get maximum frequency from FFT index max_freq = max_fr_index * 333/(512); if (max_freq > 3 && max_freq < 58) { //HIGH/LOW PASS FILTER IN SOFTWARE calm_avg = (fix2float(calm))/num_calm_samples; excited_avg = (fix2float(excited))/num_excited_samples; ratio = calm_avg/excited_avg; ratio_filter[ratio_iter] = ratio; ratio_iter++; //3-point Averaging Filter for Ratio if (ratio_iter > 2) { ratio_iter = 0; avg_ratio = (ratio_filter[0]+ratio_filter[1]+ratio_filter[2])/3; } //SET LED Based on Ratio if (avg_ratio < 0.9) { //red LED mPORTAClearBits (BIT_0); //yellow mPORTASetBits(BIT_1); //red mPORTBClearBits(BIT_5); //green } else if (avg_ratio > 0.9 && avg_ratio < 1.2) { //yellow LED mPORTASetBits (BIT_0); //yellow mPORTAClearBits(BIT_1); //red mPORTBClearBits(BIT_5); //green } else if (avg_ratio > 1.2) { //green LED mPORTAClearBits (BIT_0); //yellow mPORTAClearBits(BIT_1); //red mPORTBSetBits(BIT_5); //green } } //Code for displaying wave stats (frequency & ratio) tft_setTextColor(ILI9340_YELLOW); tft_setTextSize(1); tft_setCursor(0, 220); tft_fillRoundRect(0,220, 320, 20, 1, ILI9340_BLACK);// x,y,w,h,radius,color sprintf(buffer, "PEAK FREQ = %d, Calm = %f, \n Exc = %f, AVG_RATIO = %1.1f", max_fr_index * 333/(512), calm_avg, excited_avg, avg_ratio); tft_writeString(buffer); } adc_ready = 0; // NEVER exit while } // END WHILE(1) PT_END(pt); } // animation thread //==================================================================== // FFT void FFTfix(int fr[], int fi[], int m) //Adapted from code by: //Tom Roberts 11/8/89 and Malcolm Slaney 12/15/94 malcolm@interval.com //fr[n],fi[n] are real,imaginary arrays, INPUT AND RESULT. //size of data = 2**m // This routine does foward transform only begin int mr,nn,i,j,L,k,istep, n; int qr,qi,tr,ti,wr,wi; mr = 0; n = 1<>= 1; while(mr+L > nn); mr = (mr & (L-1)) + L; if(mr <= m) continue; tr = fr[m]; fr[m] = fr[mr]; fr[mr] = tr; //ti = fi[m]; //for real inputs, don't need this //fi[m] = fi[mr]; //fi[mr] = ti; end L = 1; k = LOG2_N_WAVE-1; while(L < n) begin istep = L << 1; for(m=0; m>= 1; wi >>= 1; for(i=m; i> 1; qi = fi[i] >> 1; fr[j] = qr - tr; fi[j] = qi - ti; fr[i] = qr + tr; fi[i] = qi + ti; end end --k; L = istep; end end // === Main ====================================================== void main(void) { //SYSTEMConfigPerformance(PBCLK); ANSELA = 0; ANSELB = 0; // === config threads ========== // turns OFF UART support and debugger pin, unless defines are set PT_setup(); // === setup system wide interrupts ======== INTEnableSystemMultiVectoredInt(); // the ADC /////////////////////////////////////// // configure and enable the ADC CloseADC10(); // ensure the ADC is off before setting the configuration // define setup parameters for OpenADC10 // Turn module on | ouput in integer | trigger mode auto | enable autosample // ADC_CLK_AUTO -- Internal counter ends sampling and starts conversion (Auto convert) // ADC_AUTO_SAMPLING_ON -- Sampling begins immediately after last conversion completes; SAMP bit is automatically set // ADC_AUTO_SAMPLING_OFF -- Sampling begins with AcquireADC10(); #define PARAM1 ADC_FORMAT_INTG16 | ADC_CLK_AUTO | ADC_AUTO_SAMPLING_OFF // // define setup parameters for OpenADC10 // ADC ref external | disable offset test | disable scan mode | do 1 sample | use single buf | alternate mode off #define PARAM2 ADC_VREF_AVDD_AVSS | ADC_OFFSET_CAL_DISABLE | ADC_SCAN_OFF | ADC_SAMPLES_PER_INT_1 | ADC_ALT_BUF_OFF | ADC_ALT_INPUT_OFF // // Define setup parameters for OpenADC10 // use peripherial bus clock | set sample time | set ADC clock divider // ADC_CONV_CLK_Tcy2 means divide CLK_PB by 2 (max speed) // ADC_SAMPLE_TIME_5 seems to work with a source resistance < 1kohm #define PARAM3 ADC_CONV_CLK_PB | ADC_SAMPLE_TIME_5 | ADC_CONV_CLK_Tcy2 //ADC_SAMPLE_TIME_15| ADC_CONV_CLK_Tcy2 // define setup parameters for OpenADC10 // set AN11 and as analog inputs #define PARAM4 ENABLE_AN11_ANA // pin 24 // define setup parameters for OpenADC10 // do not assign channels to scan #define PARAM5 SKIP_SCAN_ALL // use ground as neg ref for A | use AN11 for input A // configure to sample AN11 SetChanADC10( ADC_CH0_NEG_SAMPLEA_NVREF | ADC_CH0_POS_SAMPLEA_AN11 ); // configure to sample AN4 OpenADC10( PARAM1, PARAM2, PARAM3, PARAM4, PARAM5 ); // configure ADC using the parameters defined above EnableADC10(); // Enable the ADC /////////////////////////////////////////////////////// //Timer for ADC measurement OpenTimer3(T3_ON | T3_SOURCE_INT | T3_PS_1_2, timer_adc); ConfigIntTimer3(T3_INT_ON | T3_INT_PRIOR_2); mT3ClearIntFlag(); // and clear the interrupt flag //Turn off LEDs initially mPORTASetBits(BIT_0 | BIT_1); mPORTBSetBits(BIT_5); //Set pins 2, 3 and 14 as output pins for LEDs mPORTASetPinsDigitalOut(BIT_0 | BIT_1); //Set pins 2 & 3 as output mPORTBSetPinsDigitalOut(BIT_5); //Set pin 14 as output //Set pins 17 and 18 for switches mPORTBSetPinsDigitalIn(BIT_8); //Set pin 17 as input mPORTBSetPinsDigitalIn(BIT_9); //Set pin 18 as input // === init FFT data ===================================== // one cycle sine table // required for FFT int ii; for (ii=0; ii