calculate cpu usage with a hardware timer

had to bump the display stack size to keep snprintf from crashing

buttons.c

@@ -6,6 +6,17 @@
  *
  * ECE 3849 Lab button handling
  */
+
+/* XDCtools Header files */
+#include <xdc/std.h>
+#include <xdc/runtime/System.h>
+#include <xdc/cfg/global.h>
+
+/* BIOS Header files */
+#include <ti/sysbios/BIOS.h>
+#include <ti/sysbios/knl/Task.h>
+#include <ti/sysbios/knl/Semaphore.h>
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <math.h>
@@ -32,17 +43,6 @@ extern volatile uint32_t gTime; // time in hundredths of a second
 // initialize all button and joystick handling hardware
 void ButtonInit(void)
 {
-    // initialize a general purpose timer for periodic interrupts
-    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
-    TimerDisable(TIMER0_BASE, TIMER_BOTH);
-    TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC);
-    TimerLoadSet(TIMER0_BASE, TIMER_A, roundf((float)gSystemClock / BUTTON_SCAN_RATE) - 1);
-    TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
-    TimerEnable(TIMER0_BASE, TIMER_BOTH);
-
-    // initialize interrupt controller to respond to timer interrupts
-    IntPrioritySet(INT_TIMER0A, BUTTON_INT_PRIORITY);
-    IntEnable(INT_TIMER0A);
     // GPIO PJ0 and PJ1 = EK-TM4C1294XL buttons 1 and 2
     SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOJ);
     GPIOPinTypeGPIOInput(GPIO_PORTJ_BASE, GPIO_PIN_0 | GPIO_PIN_1);
@@ -153,9 +153,19 @@ uint32_t ButtonAutoRepeat(void)
     return presses;
 }
 
-// ISR for scanning and debouncing buttons
-void ButtonISR(void) {
-    TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT); // clear interrupt flag
+void clock_buttons(void) {
+    Semaphore_post(button_clock_sem);
+}
+
+void button_task(void) {
+    while(1) {
+        Semaphore_pend(button_clock_sem, BIOS_WAIT_FOREVER);
+        handle_buttons();
+    }
+}
+
+// Task for scanning and debouncing buttons
+void handle_buttons(void) {
     // read hardware button state
     uint32_t gpio_buttons =
             ~GPIOPinRead(GPIO_PORTJ_BASE, 0xff) & (GPIO_PIN_1 | GPIO_PIN_0); // EK-TM4C1294XL buttons in positions 0 and 1
@@ -181,25 +191,12 @@ 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
-        running = !running;
-    }
-    if (presses & 2) { // EK-TM4C1294XL button 2 pressed
-        gTime = 0;
-    }
-    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]);
+        Mailbox_post(button_mailbox,buttons+i, BIOS_WAIT_FOREVER);
     }
 }
 
@@ -217,39 +214,3 @@ uint8_t buttons_from_mask(Button *array, uint32_t buttons) {
 
     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

@@ -69,9 +69,6 @@ typedef enum {
 // 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);
+void handle_buttons(void);
 
 #endif /* BUTTONS_H_ */

main.c

@@ -34,6 +34,10 @@
 
 uint32_t gSystemClock = 120000000; // [Hz] system clock frequency
 
+tContext sContext;
+
+uint32_t cputime_unloaded;
+
 #define LOCAL_BUF_LEN 128
 uint16_t adc_buffer_sample[LOCAL_BUF_LEN]; // copy of g adc buffer
 uint8_t adc_buffer_processed[LOCAL_BUF_LEN]; // copy of g adc buffer
@@ -98,6 +102,26 @@ 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();
+}
+
 /*
  *  ======== main ========
  */
@@ -108,6 +132,14 @@ int main(void)
     // hardware initialization goes here
     start_signal();
     start_sampler();
+    ButtonInit();
+    start_cputimer();
+
+    Crystalfontz128x128_Init(); // Initialize the LCD display driver
+    Crystalfontz128x128_SetOrientation(LCD_ORIENTATION_UP); // set screen orientation
+
+    GrContextInit(&sContext, &g_sCrystalfontz128x128); // Initialize the grlib graphics context
+    GrContextFontSet(&sContext, &g_sFontFixed6x8); // select font
 
     /* Start BIOS */
     BIOS_start();
@@ -126,6 +158,7 @@ void task0_func(UArg arg1, UArg arg2)
 
 void capture_waveform(UArg arg1, UArg arg2)
 {
+    IntMasterEnable();
     while(true) {
         Semaphore_pend(capture_sem, BIOS_WAIT_FOREVER);
 
@@ -168,8 +201,111 @@ void process_waveform(UArg arg1, UArg arg2) {
     }
 }
 
+void handle_user_input() {
+    // handle buttons
+    Button button = (Button) 0;
+    while (true) {
+        Mailbox_pend(button_mailbox, &button, BIOS_WAIT_FOREVER);
+
+        switch (button) {
+            case S1: // toggle edge
+                trigger_mode++;
+                trigger_mode %= 3;
+                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;
+        }
+    }
+}
+
 void display_waveform(UArg arg1, UArg arg2)
 {
+    char str[50];   // string buffer
+    tRectangle rectFullScreen = {0, 0, GrContextDpyWidthGet(&sContext)-1, GrContextDpyHeightGet(&sContext)-1};
+
+    while(1) {
+        Semaphore_pend(display_sem, BIOS_WAIT_FOREVER);
+
+        // 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.;
+
+        GrContextForegroundSet(&sContext, ClrBlack);
+        GrRectFill(&sContext, &rectFullScreen); // fill screen with black
+
+        GrContextForegroundSet(&sContext, ClrBlue);
+
+        // draw gridlines from the center out
+        uint8_t xy_pos;
+        for (xy_pos = HEIGHT/2; xy_pos < HEIGHT; xy_pos += PIXELS_PER_DIV) {
+            GrLineDrawV(&sContext, xy_pos, 0, 128); // right
+            GrLineDrawV(&sContext, HEIGHT - xy_pos, 0, 128); // left
+
+            GrLineDrawH(&sContext, 0, 128, xy_pos); // down
+            GrLineDrawH(&sContext, 0, 128, HEIGHT - xy_pos); // up
+        }
+
+
+        // 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);
+
+        switch (trigger_mode) {
+            case 1:
+                GrStringDraw(&sContext, "^", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
+                break;
+            case 0:
+                GrStringDraw(&sContext, "v", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
+                break;
+            case 2:
+                GrStringDraw(&sContext, "-", /*length*/ -1, /*x*/ WIDTH - 10, /*y*/ 0, /*opaque*/ false);
+                break;
+        }
+
+        // display graph
+        GrContextForegroundSet(&sContext, ClrYellow);
+        int j;
+        for(j=0; j<LOCAL_BUF_LEN; j++) {
+            #define MIN(a,b) (((a)<(b))?(a):(b))
+            #define MAX(a,b) (((a)>(b))?(a):(b))
+            uint32_t upper,lower, current, last;
+
+            if (j==0) {
+                upper = adc_buffer_processed[j];
+                lower = upper;
+                last = upper;
+            } else {
+                current = adc_buffer_processed[j];
+
+                upper = MAX(current, last);
+                lower = MIN(current, last);
+
+                last = current;
+            }
+
+            GrLineDrawV(&sContext, j, lower, upper);
+        }
+
+        GrFlush(&sContext); // flush the frame buffer to the LCD
+
+    }
 }
 
 

rtos.cfg

@@ -566,10 +566,30 @@ task2Params.priority = 2;
 Program.global.processing = Task.create("&process_waveform", task2Params);
 var task3Params = new Task.Params();
 task3Params.instance.name = "display";
-task3Params.priority = 3;
-task3Params.stackSize = 1024;
+task3Params.priority = 5;
+task3Params.stackSize = 2048;
 Program.global.display = Task.create("&display_waveform", task3Params);
 var semaphore2Params0 = new Semaphore.Params();
 semaphore2Params0.instance.name = "display_sem";
 semaphore2Params0.mode = Semaphore.Mode_BINARY;
 Program.global.display_sem = Semaphore.create(null, semaphore2Params0);
+var clock0Params = new Clock.Params();
+clock0Params.instance.name = "button_clock";
+clock0Params.period = 5;
+clock0Params.startFlag = true;
+Program.global.button_clock = Clock.create("&clock_buttons", 1, clock0Params);
+var semaphore3Params = new Semaphore.Params();
+semaphore3Params.instance.name = "button_clock_sem";
+semaphore3Params.mode = Semaphore.Mode_BINARY;
+Program.global.button_clock_sem = Semaphore.create(null, semaphore3Params);
+var task4Params = new Task.Params();
+task4Params.instance.name = "button";
+task4Params.priority = 14;
+Program.global.button = Task.create("&button_task", task4Params);
+var mailbox0Params = new Mailbox.Params();
+mailbox0Params.instance.name = "button_mailbox";
+Program.global.button_mailbox = Mailbox.create(1, 9, mailbox0Params);
+var task5Params = new Task.Params();
+task5Params.instance.name = "user_input";
+task5Params.priority = 6;
+Program.global.user_input = Task.create("&handle_user_input", task5Params);