buttons.c

@@ -28,6 +28,7 @@ uint32_t gADCSamplingRate;      // [Hz] actual ADC sampling rate
 // imported globals
 extern uint32_t gSystemClock;   // [Hz] system clock frequency
 extern volatile uint32_t gTime; // time in hundredths of a second
+extern volatile uint8_t drawRequested;
 
 // initialize all button and joystick handling hardware
 void ButtonInit(void)
@@ -181,7 +182,6 @@ void ButtonISR(void) {
     ButtonReadJoystick();               // Convert joystick state to button presses. The result is in gButtons.
     uint32_t presses = ~old_buttons & gButtons;   // detect button presses (transitions from not pressed to pressed)
     presses |= ButtonAutoRepeat();      // autorepeat presses if a button is held long enough
-#ifdef DISPLAY_TIME
     static bool tic = false;
     static bool running = true;
     if (presses & 1) { // EK-TM4C1294XL button 1 pressed
@@ -190,66 +190,11 @@ void ButtonISR(void) {
     if (presses & 2) { // EK-TM4C1294XL button 2 pressed
         gTime = 0;
     }
+    if (presses & 4) { // boosterpack button 1 pressed
+        drawRequested = 1;
+    }
     if (running) {
         if (tic) gTime++; // increment time every other ISR call
         tic = !tic;
     }
-#endif // DISPLAY_TIME
-    Button buttons[9];
-    uint8_t length, i;
-    length = buttons_from_mask(buttons, presses);
-    for (i=0; i<length; i++) {
-        fifo_put(buttons[i]);
-    }
-}
-
-uint8_t buttons_from_mask(Button *array, uint32_t buttons) {
-    uint8_t i, len;
-    len = 0;
-
-    for(i=0; i<9; i++) {
-        if (buttons & 1) {
-            array[len++] = (Button) i;
-        }
-
-        buttons >>= 1;
-    }
-
-    return len;
-}
-
-volatile DataType button_fifo[FIFO_SIZE];  // FIFO storage array
-volatile int fifo_head = 0; // index of the first item in the FIFO
-volatile int fifo_tail = 0; // index one step past the last item
-
-// put data into the FIFO, skip if full
-// returns 1 on success, 0 if FIFO was full
-int fifo_put(DataType data)
-{
-    int new_tail = fifo_tail + 1;
-    if (new_tail >= FIFO_SIZE) new_tail = 0; // wrap around
-    if (fifo_head != new_tail) {    // if the FIFO is not full
-        button_fifo[fifo_tail] = data;     // store data into the FIFO
-        fifo_tail = new_tail;       // advance FIFO tail index
-        return 1;                   // success
-    }
-    return 0;   // full
-}
-
-// get data from the FIFO
-// returns 1 on success, 0 if FIFO was empty
-int fifo_get(DataType *data)
-{
-    if (fifo_head != fifo_tail) {   // if the FIFO is not empty
-        *data = button_fifo[fifo_head];    // read data from the FIFO
-        
-        if (fifo_head >= FIFO_SIZE-1) {
-            fifo_head = 0; // reset if past end
-        } else {
-            fifo_head++; // increment if within buffer
-        }
-
-        return 1;                   // success
-    }
-    return 0;   // empty
 }

buttons.h

@@ -27,8 +27,8 @@
 #define BUTTON_AUTOREPEAT_INITIAL 100   // how many samples must read pressed before autorepeat starts
 #define BUTTON_AUTOREPEAT_NEXT 10       // how many samples must read pressed before the next repetition
 
-#define JOYSTICK_UPPER_PRESS_THRESHOLD 2200     // above this ADC value, button is pressed
+#define JOYSTICK_UPPER_PRESS_THRESHOLD 2100     // above this ADC value, button is pressed
-#define JOYSTICK_UPPER_RELEASE_THRESHOLD 2100   // below this ADC value, button is released
+#define JOYSTICK_UPPER_RELEASE_THRESHOLD 2000   // below this ADC value, button is released
 #define JOYSTICK_LOWER_PRESS_THRESHOLD 1700      // below this ADC value, button is pressed
 #define JOYSTICK_LOWER_RELEASE_THRESHOLD 1800   // above this ADC value, button is released
 
@@ -52,26 +52,4 @@ void ButtonReadJoystick(void);
 // autorepeat button presses if a button is held long enough
 uint32_t ButtonAutoRepeat(void);
 
-typedef enum {
-    SW1 = 0,
-    SW2,
-    S1,
-    S2,
-    Select,
-    Right,
-    Left,
-    Up,
-    Down,
-} Button;
-
-// convert mask into array of buttons
-//
-// returns length
-uint8_t buttons_from_mask(Button *array, uint32_t buttons);
-
-#define FIFO_SIZE 11        // FIFO capacity is 1 item fewer
-typedef Button DataType;      // FIFO data type
-int fifo_put(DataType data);
-int fifo_get(DataType *data);
-
 #endif /* BUTTONS_H_ */

main.c

@@ -13,7 +13,6 @@
 #include "driverlib/fpu.h"
 #include "driverlib/sysctl.h"
 #include "driverlib/interrupt.h"
-#include "driverlib/timer.h"
 #include "Crystalfontz128x128_ST7735.h"
 #include <stdio.h>
 #include "grlib/grlib.h"
@@ -29,43 +28,7 @@
 
 uint32_t gSystemClock; // [Hz] system clock frequency
 volatile uint32_t gTime = 0; // time in hundredths of a second
-volatile uint8_t refresh = 1;
+volatile uint8_t drawRequested = 1;
-
-// assumming square lcd
-#define HEIGHT LCD_VERTICAL_MAX
-#define WIDTH LCD_HORIZONTAL_MAX
-#define PIXELS_PER_DIV 20
-
-#define VIN_RANGE 3.3 // volts
-#define ADC_BITS 12
-#define ADC_OFFSET 30
-
-#define VOLTAGE_SCALES 5
-const char * const gVoltageScaleStr[VOLTAGE_SCALES] = {
-"100 mV", "200 mV", "500 mV", " 1 V", " 2 V"
-};
-
-const float gVoltageScale[VOLTAGE_SCALES] = {
-    0.1, 0.2, 0.5, 1., 2.
-};
-
-#define TIME_SCALES 6
-const char * const gTimeScaleStr[TIME_SCALES] = {
-"100 ms", "50 ms", "20 ms", " 10 ms", "50 us", "20 us"
-};
-
-const uint64_t gTImeScale[TIME_SCALES] = {
-    100 * 1000 / PIXELS_PER_DIV,
-    50 * 1000 / PIXELS_PER_DIV,
-    20 * 1000 / PIXELS_PER_DIV,
-    10 * 1000 / PIXELS_PER_DIV,
-    50 / PIXELS_PER_DIV,
-    20 / PIXELS_PER_DIV,
-};
-
-uint32_t cputime_unloaded;
-
-int Trigger(bool rising);
 
 // start a pwm test signal
 void start_signal() {
@@ -89,26 +52,6 @@ void start_signal() {
   PWMGenEnable(PWM0_BASE, PWM_GEN_1);
 }
 
-uint32_t cpu_load_count(void)
-{
-    uint32_t i = 0;
-    TimerIntClear(TIMER1_BASE, TIMER_TIMA_TIMEOUT);
-    TimerEnable(TIMER1_BASE, TIMER_A); // start one-shot timer
-    while (!(TimerIntStatus(TIMER1_BASE, false) & TIMER_TIMA_TIMEOUT))
-        i++;
-    return i;
-}
-
-void start_cputimer() {
-    // initialize timer 1 in one-shot mode for polled timing
-    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);
-    TimerDisable(TIMER1_BASE, TIMER_BOTH);
-    TimerConfigure(TIMER1_BASE, TIMER_CFG_ONE_SHOT);
-    TimerLoadSet(TIMER1_BASE, TIMER_A, gSystemClock/100); // 10ms interval
-    // baseline load
-    cputime_unloaded = cpu_load_count();
-}
-
 int main(void) {
     IntMasterDisable();
 
@@ -128,60 +71,21 @@ int main(void) {
     GrContextInit(&sContext, &g_sCrystalfontz128x128); // Initialize the grlib graphics context
     GrContextFontSet(&sContext, &g_sFontFixed6x8); // select font
 
-#ifdef DISPLAY_TIME
     uint32_t time;  // local copy of gTime
-#endif // DISPLAY_TIME
     char str[50];   // string buffer
-    
     // full-screen rectangle
     tRectangle rectFullScreen = {0, 0, GrContextDpyWidthGet(&sContext)-1, GrContextDpyHeightGet(&sContext)-1};
 
     ButtonInit();
-
-    start_cputimer();
-
     IntMasterEnable();
 
-    uint8_t voltage_scale = 0;
-    uint8_t time_scale = 0;
-    uint8_t rising = 1;
-
     while (true) {
-        // calculate cpu usage
-        uint32_t cputime_loaded;
-        cputime_loaded = cpu_load_count();
-        float usage_percent;
-        usage_percent = (1.0 - (float) cputime_loaded / (float) cputime_unloaded) * (float) 100.;
-
-        // handle buttons
-        Button button = (Button) 0;
-        while (fifo_get(&button)) {
-            switch (button) {
-                case S1: // toggle edge
-                    rising = !rising;
-                    break;
-                case S2: // draw
-                    refresh = !refresh;
-                    break;
-                case Up: // next scale
-                    voltage_scale = (voltage_scale + 1) % VOLTAGE_SCALES;
-                    break;
-                case Down: // previous scale
-                    voltage_scale = (voltage_scale + VOLTAGE_SCALES - 1) % VOLTAGE_SCALES;
-                    break;
-                case Right: // next scale
-                    time_scale = (time_scale + 1) % TIME_SCALES;
-                    set_frequency(gTImeScale[time_scale]);
-                    break;
-                case Left: // previous scale
-                    time_scale = (time_scale + TIME_SCALES - 1) % TIME_SCALES;
-                    set_frequency(gTImeScale[time_scale]);
-                    break;
-            }
-        }
-
         GrContextForegroundSet(&sContext, ClrBlack);
         GrRectFill(&sContext, &rectFullScreen); // fill screen with black
+        
+        // assumming square lcd
+        #define HEIGHT LCD_VERTICAL_MAX
+        #define PIXELS_PER_DIV 20
 
         GrContextForegroundSet(&sContext, ClrBlue);
 
@@ -196,39 +100,22 @@ int main(void) {
         }
 
 
-        // info
-        GrContextForegroundSet(&sContext, ClrWheat);
-        GrStringDraw(&sContext, gVoltageScaleStr[voltage_scale], /*length*/ -1, /*x*/ 0, /*y*/ 0, /*opaque*/ false);
-        GrStringDraw(&sContext, gTimeScaleStr[time_scale], /*length*/ -1, /*x*/ 60, /*y*/ 0, /*opaque*/ false);
-        snprintf(str, sizeof(str), "CPU Load %.1f%%", usage_percent); 
-        GrStringDraw(&sContext, str, /*length*/ -1, /*x*/ 0, /*y*/ HEIGHT - 10, /*opaque*/ false);
-
-        if (rising) {
-            GrStringDraw(&sContext, "^", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
-        } else {
-            GrStringDraw(&sContext, "v", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
-        }
-
         // display graph
         #define LOCAL_BUF_LEN 128
         uint16_t local_adc_buffer[LOCAL_BUF_LEN]; // copy of adc buffer
         int32_t adc_current_index;
         int32_t j;
-        if (refresh) {
+        if (drawRequested) {
-            int trigger = Trigger(rising);
+            adc_current_index = gADCBufferIndex - 128;
-
-            adc_current_index = trigger - (WIDTH / 2);
             for (j=0; j<LOCAL_BUF_LEN; j++) {
                 local_adc_buffer[j] = gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + j)];
             }
+            drawRequested = 0;
         }
 
-        float fVoltsPerDiv = gVoltageScale[voltage_scale];
-        float fScale = (VIN_RANGE * PIXELS_PER_DIV)/((1 << ADC_BITS) * fVoltsPerDiv);
-
         GrContextForegroundSet(&sContext, ClrPink);
         for(j=0; j<LOCAL_BUF_LEN; j++) {
-            #define TRANSPOSE(x) (HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET));
+            #define TRANSPOSE(x) (HEIGHT/2) - (x >> 6) // reduce from twelve to six bits, then flip and center
             uint32_t upper,lower, current, last;
 
             if (j==0) {
@@ -284,25 +171,3 @@ int main(void) {
         GrFlush(&sContext); // flush the frame buffer to the LCD
     }
 }
-
-int Trigger(bool rising) // search for edge trigger
-{
-    int x = gADCBufferIndex - (WIDTH / 2); // half screen width
-    int x_stop = x - ADC_BUFFER_SIZE/2;
-    for (; x > x_stop; x--) {
-        if (rising) {
-            if ( gADCBuffer[ADC_BUFFER_WRAP(x)] >= ADC_OFFSET &&
-                gADCBuffer[ADC_BUFFER_WRAP(x-1)] < ADC_OFFSET) {
-                break;
-            }
-        } else { // falling edge trigger
-            if ( gADCBuffer[ADC_BUFFER_WRAP(x)] <= ADC_OFFSET &&
-                gADCBuffer[ADC_BUFFER_WRAP(x-1)] > ADC_OFFSET) {
-                break;
-            }
-        }
-    }
-    if (x == x_stop) // for loop ran to the end
-    x = x = gADCBufferIndex - (WIDTH / 2); // reset x back to how it was initialized
-    return x;
-}

sampling.c

@@ -6,7 +6,6 @@
 #include "driverlib/gpio.h"
 #include "driverlib/sysctl.h"
 #include "driverlib/interrupt.h"
-#include "driverlib/timer.h"
 #include "sysctl_pll.h"
 #include "inc/hw_types.h"
 #include "inc/hw_memmap.h"
@@ -14,8 +13,6 @@
 #include "buttons.h"
 #include "sampling.h"
 
-extern uint32_t gSystemClock;   // [Hz] system clock frequency
-
 // latest sample index
 void ADC_ISR(void)
 {
@@ -44,9 +41,6 @@ void start_sampler() {
     // initialize ADC peripherals
     SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
     SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC1);
-
-    // timer for low-speed
-    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER2);
     // ADC clock
     uint32_t pll_frequency = SysCtlFrequencyGet(CRYSTAL_FREQUENCY);
     uint32_t pll_divisor =
@@ -70,25 +64,3 @@ void start_sampler() {
     // enable ADC1 sequence 0 interrupt in int. controller
     IntEnable(INT_ADC1SS0);
 }
-
-void set_frequency(uint64_t microseconds) {
-    if (microseconds == 1) {
-        ADCSequenceDisable(ADC1_BASE, 0);
-        // don't use a timer for high speed
-        ADCSequenceConfigure(ADC1_BASE, 0, ADC_TRIGGER_ALWAYS, 0);
-        ADCSequenceEnable(ADC1_BASE, 0);
-        return;
-    }
-
-    // initialize timer 2 in periodic mode
-    TimerDisable(TIMER2_BASE, TIMER_BOTH);
-    TimerConfigure(TIMER2_BASE, TIMER_CFG_PERIODIC);
-    #define MICROSECONDS_PER_SECOND 1000000
-    TimerLoadSet(TIMER2_BASE, TIMER_A, (uint32_t) ((uint64_t) gSystemClock * microseconds / MICROSECONDS_PER_SECOND) - 1);
-    TimerControlTrigger(TIMER2_BASE, TIMER_A, true);
-    TimerEnable(TIMER2_BASE, TIMER_A);
-
-    ADCSequenceDisable(ADC1_BASE, 0);
-    ADCSequenceConfigure(ADC1_BASE, 0, ADC_TRIGGER_TIMER, 0);
-    ADCSequenceEnable(ADC1_BASE, 0);
-}

sampling.h

@@ -15,6 +15,4 @@ volatile uint32_t gADCErrors; // number of missed ADC deadlines
 // initialize ADC and ISR
 void start_sampler(void);
 
-void set_frequency(uint64_t microseconds);
-
 #endif /* SAMPLING_H_ */