Added solutions for many of the first exercises

9 files changed, 417 insertions, 48 deletions

diff --git a/sem4/embedded/eksamnen/M1f1.png b/sem4/embedded/eksamnen/M1f1.png
new file mode 100644
index 0000000..ef8238d
--- /dev/null
+++ b/sem4/embedded/eksamnen/M1f1.png
diff --git a/sem4/embedded/eksamnen/M7opg.adoc b/sem4/embedded/eksamnen/M7opg.adoc
index c4b32f6..4be491a 100644
--- a/sem4/embedded/eksamnen/M7opg.adoc
+++ b/sem4/embedded/eksamnen/M7opg.adoc
@@ -16,21 +16,8 @@ ____
 _Does utilization guarantee feasibility of an RMA schedule?_
 ____
 
-
-Først regner jeg utilization ud.
-
-----
-U = 20/50 + 20/80 = 0.65
-----
-
-Derefter kan man regne utilization critereon ud.
-
-----
-\overline{U} = 2 * (2^(1/2) - 1) = 0.82
-----
-
-Her kan man garantere at RMA er schedulable.
-
+Nej det kan man ikke.
+Hvis deadlines havde været samme som periode kunne man regne stem:[\overline{U}] ud.
 ____
 _Validate an RMA schedule with the exact schedulability criterion._
 ____
diff --git a/sem4/embedded/eksamnen/notes.adoc b/sem4/embedded/eksamnen/notes.adoc
index 5ff6874..736c275 100644
--- a/sem4/embedded/eksamnen/notes.adoc
+++ b/sem4/embedded/eksamnen/notes.adoc
@@ -9,6 +9,69 @@ ____
 
 TODO med arduino. Og debouncer.
 
+== Opgave løsning
+
+____
+_Design and implement an interrupt service routine which acts on digital pin 2._
+____
+
+Digital pin 2 i arduino er mapped til atmega328p pin PD2, og er koblet på INT0.
+Derfor starter vi med at enable INT0.
+
+Se for kode ../m1/int/int.ino
+
+----
+EIMSK |= 1 << INT0;
+----
+
+Derefter kan man lave en interrupt der trigger på rising edge, hvilket man ud
+fra datasheet kan se er ISC01 og ISC00 i EICRAfor INT0.
+
+----
+EICRA |= (1 << ISC01) | (1 << ISC00);
+----
+
+Hvis man har sat den rigtige pinmode på 2, vil interrupten nu være aktiveret.
+
+----
+ISR(INT0_vect) {
+    do_the_thing();
+}
+----
+
+Her bruger jeg en normal ISR, hvor gcc håndtere det med at push registre på
+stakken og sætte dem tilbage igen efter.
+
+Dette kan man også se i den compilede fil.
+
+image::M1f1.png[]
+
+____
+_Or add a timed decision in ISR to prevent more ISR response for the nex xx mseconds._
+____
+
+Dette er gjort ved at gemme tiden for hver gang den kører med millis.
+Derefter kan man check om det er over 100 ms siden at man sidst kørte.
+
+____
+_Design a tick routing which can run a function on given times (and explain code below_
+____
+
+Har lavet en function man kalder for hver tasks man vil tick route.
+Denne bruger millis() funktionen som bagved bruger timer0.
+
+____
+_What is limitations ? like timewise  starvation,..._
+____
+
+Man kan tydelig se problemet hvis man sætter task0 til at have et 10000 ms langt
+delay.
+
+Her vil man se starvation i at det hele bliver langsomere.
+
+Dette er fordi det ikke er preimtive hvilket betyder at hvis et job bare tager lang
+tid må de andre bare vente.
+
 === Noter
 
 Findes forskellige slags realtime afhængig af hvor vigtigt det er at man
@@ -26,9 +89,56 @@ ____
 Exercise 1-11
 ____
 
+=== Løsning
+
 See ../emb_m2/emb_m2.ino
 
-TODO med arduino
+____
+_Compute the mean relative error between da and mda_
+____
+
+0.0052564806 hvilket er okay for at den kun er 16 bit.
+
+____
+_Compute the mean relative error between da2 and mda2_
+____
+
+0.1998619556 her kan man se at fejlen stiger en del.
+
+____
+_Iterate "a*=da[i];" over the length of da and measure the execution time (micros())_
+____
+
+Exe time: 1272
+
+____
+_Iterate "mult_float(&f1,&mda[i],&f); memcpy(&f1,&f,2);" over the length of mda and measure the execution time_
+____
+
+Exe time: 828
+
+____
+_Compute the relative difference between results from (7) and (9)_
+____
+
+----
+Abs diff: 444
+Rel diff: 0.35
+----
+
+____
+_Implement the fastest version of the trigornometric function "sine" that has below 2% relative error._
+____
+
+Her brugte jeg tayler til at exporimere sin(x).
+Dette blev ret præcis men var meget langsomere end sin(x).
+
+----
+TOTAL STATS
+rel err : 0.0005467962
+own time: 2420
+ard time: 134
+----
 
 === Noter
 
@@ -56,7 +166,48 @@ ____
 Exercise 4-7
 ____
 
-TODO lav det her på arduino.
+=== Løsning
+
+Her har jeg lavet noget test data med to beskeder, dette løser den ret godt.
+
+Jeg bruger bare uint8_t til de to først typer.
+
+Se ../m3/m3.ino
+
+----
+DONE
+Type            :1
+Recvid          :514
+Transducerlevel :88
+Quiettime       :50
+Masters         :1
+
+MASTER: 0
+    rssi        :90
+    txid        :5
+    ixidtime    :600
+DONE
+Type            :65
+Recvid          :1
+Transducerlevel :136
+Quiettime       :16
+Masters         :3
+
+MASTER: 0
+    rssi        :23
+    txid        :68
+    ixidtime    :65535
+
+MASTER: 1
+    rssi        :11
+    txid        :171
+    ixidtime    :65534
+
+MASTER: 2
+    rssi        :3
+    txid        :64
+    ixidtime    :65535
+----
 
 === Noter
 
@@ -91,10 +242,15 @@ ____
 Show LED13 blink code and explain program.
 ____
 
+Se ../emb_m4/emb_m4.ino
+
 ____
 Explain interrupt
 ____
 
+Se ../emb_m4/jrnl/jrnl.ino
+Se ../m1/int/int.ino
+
 ____
 Lack of control maybe bq of non-interruptable ISRs
 ____
@@ -103,10 +259,27 @@ ____
 Procesmodel: running,ready,blocked
 ____
 
+Man kan se at processorne bruger k_sleep, hvilket gør dem blocked.
+Når de er færdige med at sleep kommer de i ready, og når de så bliver scheduled
+kommer de i running.
+
 ____
 semaphore wait and signal
 ____
 
+Dette kan man bruge til forskellige ting.
+
+Critical region::
+    Man har noget kode der tilgår noget data.
+    Dette kan man låse ved at lave en semafor med en start værdi på 1.
+    Når nogen låser den tager de den værdi.
+Periodisk timing::
+    Man kan sætte os til at signal ens semafor hvert x sekundt.
+    Her giver man start værdi 0.
+Timing og beskeder::
+    Det er en god måde at synkronisere forskellige task.
+    For eksempel kan en ISR sætte en semafor for at signalere at der er en ny besked.
+
 == J3 module 5
 
 ____
@@ -114,12 +287,16 @@ What is a semaphore, show code from above and eplaing critical region
 setup
 ____
 
+Se ../m5/m5.ino
+
 == J4 module 6
 
 ____
 Show code for and explain message queues as a buffering tool.
 ____
 
+Se ../m6/m6.ino
+
 == J5 module 6.5
 
 ____
diff --git a/sem4/embedded/emb_m2/emb_m2.ino b/sem4/embedded/emb_m2/emb_m2.ino
index c6a6a07..b90e7f0 100644
--- a/sem4/embedded/emb_m2/emb_m2.ino
+++ b/sem4/embedded/emb_m2/emb_m2.ino
@@ -55,15 +55,19 @@ double sine(double x) {
 	// Works by finding value in specific -pi/2 to pi/2 period.
 	int period = x / TAU;
 
+	// Remember to multiply with sign
+	int sign = x < 0 ? -1 : 1;
+
 	// One cycle of sin takes 4 periods.
 	// If 0 just return the sine approx x
 	// If 1 do negative sine approx on x - TAU
 	// If 2 do negative sine approx x
 	// If 3 do sine approx on period x - TAU
-	x = abs(x - TAU*period);
+	x = abs(x) - abs(TAU*period);
 
 	double res = 12;
 	
+    Serial.print("Period "); Serial.println(abs(period % 4));
 	switch( abs(period % 4) ) {
 		case 0:
 			res = sineTayler(x, TAYLORN);
@@ -78,8 +82,6 @@ double sine(double x) {
 			res = sineTayler(x - TAU, TAYLORN);
 			break;
 	}
-	// Remember to multiply with sign
-	int sign = period < 0 ? -1 : 1;
 
 	// Should never return because all cases are handled
 	return res * sign;
@@ -210,21 +212,42 @@ void setup() {
 	NEXT_OPG(opg_count);
 	// OPG11. Impl sine
 	// Hardest value should be TAU as it's the furthest from center.
-	unsigned long begin = micros();
-	double res = sine(TAU);
-	unsigned long time1 = micros() - begin;
-	Serial.print("own sin : "); Serial.println(res, PRINT_PRECISION);
-
-	begin = micros();
-	double correct = sin(TAU);
-	unsigned long time2 = micros() - begin;
-	Serial.print("ard sin : "); Serial.println(correct, PRINT_PRECISION);
-
-	double error = correct ? abs(correct - res) / abs(correct) : 0;
-	Serial.print("rel err : "); Serial.println(error, PRINT_PRECISION);
-
-	Serial.print("\nown time: "); Serial.println(time1);
-	Serial.print("ard time: "); Serial.println(time2);
+#define STEPS 100
+    double start = -100;
+    double end = 100;
+    double step = (end - start) / (STEPS-1);
+    unsigned long owntotaltime = 0;
+    unsigned long ardtotaltime = 0;
+    double totalerror = 0;
+    for (int i = 0; i < STEPS; i++) {
+        Serial.print("\n\nInput: "); Serial.println(start, PRINT_PRECISION);
+
+        unsigned long begin = micros();
+        double res = sine(start);
+        unsigned long time1 = micros() - begin;
+        Serial.print("own sin : "); Serial.println(res, PRINT_PRECISION);
+
+        begin = micros();
+        double correct = sin(start);
+        unsigned long time2 = micros() - begin;
+        Serial.print("ard sin : "); Serial.println(correct, PRINT_PRECISION);
+
+        double error = correct ? abs(correct - res) / abs(correct) : 0;
+        Serial.print("rel err : "); Serial.println(error, PRINT_PRECISION);
+
+        Serial.print("own time: "); Serial.println(time1);
+        Serial.print("ard time: "); Serial.println(time2);
+
+        owntotaltime += time1;
+        ardtotaltime += time2;
+        totalerror += error;
+
+        start += step;
+    }
+    Serial.println("\n\nTOTAL STATS");
+    Serial.print("rel err : "); Serial.println(totalerror / STEPS, PRINT_PRECISION);
+    Serial.print("own time: "); Serial.println(owntotaltime / STEPS);
+    Serial.print("ard time: "); Serial.println(ardtotaltime / STEPS);
 
 }
 
diff --git a/sem4/embedded/emb_m4/emb_m4.ino b/sem4/embedded/emb_m4/emb_m4.ino
index 179f2b6..7e5ff48 100644
--- a/sem4/embedded/emb_m4/emb_m4.ino
+++ b/sem4/embedded/emb_m4/emb_m4.ino
@@ -7,8 +7,9 @@ char stk2[STACK];
 struct k_t *tsk1, *tsk2;
 
 void f1() {
-	for(;;) {
-		Serial.println("Haha");
+	for(int i = 0;;i++) {
+		Serial.println(i);
+        k_sleep(400);
 	}
 }
 void f2() {
@@ -16,7 +17,7 @@ void f2() {
 	for(;;) {
 		digitalWrite(13, state);
 		state = !state;
-		k_sleep(1000);
+		k_sleep(100);
 	}
 }
 
diff --git a/sem4/embedded/m1/int/int.ino b/sem4/embedded/m1/int/int.ino
index 8978be7..c4a2c31 100644
--- a/sem4/embedded/m1/int/int.ino
+++ b/sem4/embedded/m1/int/int.ino
@@ -4,19 +4,21 @@
 #define DEBOUNCE 1
 
 ISR(INT0_vect) {
-	static bool state = 0;
+    static unsigned long last = 0;
 
-	// Toggle LEDPIN
-	digitalWrite(LEDPIN, state);
-	state = !state;
+    unsigned long now = millis();
+    if (now - last < 100) {
+        return;
+    }
+    last = now;
+
+	static unsigned char state = 0;
 
-	/*
-	for(long i = 0; i < 1000; i++) {
-		Serial.print("Hej ");
-		Serial.println(i);
+	// Toggle LEDPIN
+	digitalWrite(LEDPIN, state % 2 == 0);
+	state++;
+    Serial.print("Hej "); Serial.println(state);
 
-	}
-	*/
 }
 
 void setup() {
diff --git a/sem4/embedded/m1/router/router.ino b/sem4/embedded/m1/router/router.ino
new file mode 100644
index 0000000..ba0b375
--- /dev/null
+++ b/sem4/embedded/m1/router/router.ino
@@ -0,0 +1,47 @@
+#define LEDPIN 13
+
+int task1(void) {
+    static bool state = 0;
+
+    digitalWrite(LEDPIN, state);
+    state = !state;
+    return 0;
+}
+
+int task2(void) {
+    Serial.print("l");
+    return 0;
+}
+int task3(void) {
+    Serial.print("h");
+    return 0;
+}
+
+int runevery(int (*f)(), unsigned long *last, unsigned long period) {
+    unsigned long now = millis();
+    if (*last + period > now) {
+        return -1;
+    }
+
+    *last = now;
+    return (*f)();
+}
+
+
+#define TASKS 3
+unsigned long lasts[TASKS];
+
+void setup() {
+    Serial.begin(115200);
+    pinMode(LEDPIN, OUTPUT);
+    for (int i = 0; i < TASKS; i++) {
+        lasts[i] = 0;
+    }
+}
+
+void loop() {
+    unsigned i = 0;
+    runevery(task1, &lasts[i++], 1000);
+    runevery(task2, &lasts[i++], 100);
+    runevery(task3, &lasts[i++], 10);
+}
diff --git a/sem4/embedded/m5/m5.ino b/sem4/embedded/m5/m5.ino
new file mode 100644
index 0000000..496e33b
--- /dev/null
+++ b/sem4/embedded/m5/m5.ino
@@ -0,0 +1,65 @@
+#include <krnl.h>
+#define STACK 200
+
+char stk1[STACK];
+char stk2[STACK];
+struct k_t *tsk1, *tsk2, *sem;
+
+unsigned long shared1 = 0;
+unsigned long shared2 = 0;
+
+#define DELAY 100000
+void f1() {
+	for(;;) {
+        for (int i = 0; i < DELAY/4; i++);
+        unsigned long s1 = shared1;
+
+        // Lock
+        k_wait(sem, 0);
+        unsigned long s2 = shared2;
+        // Unlock
+        k_signal(sem);
+
+        if (s1 != 0) {
+            Serial.print("S1: "); Serial.println(s1);
+        }
+        if (s2 != 0) {
+            Serial.print("S2: "); Serial.println(s2);
+        }
+	}
+}
+
+void f2() {
+	for(;;) {
+        shared1 += 1;
+        for (int i = 0; i < DELAY; i++);
+        shared1 -= 1;
+
+        // Lock
+        k_wait(sem, 0);
+        shared2 += 1;
+        for (int i = 0; i < DELAY; i++);
+        shared2 -= 1;
+        // Unlock
+        k_signal(sem);
+	}
+}
+
+void setup() {
+    pinMode(13, OUTPUT);
+    Serial.begin(115200);
+    Serial.println("Starting");
+
+    k_init(2, 1, 0);
+
+    sem = k_crt_sem(1, 1);
+
+    tsk1 = k_crt_task(f1, 10, stk1, STACK);
+    tsk2 = k_crt_task(f2, 10, stk2, STACK);
+
+    k_start(1); 
+}
+
+void loop() {
+
+}
diff --git a/sem4/embedded/m6/m6.ino b/sem4/embedded/m6/m6.ino
new file mode 100644
index 0000000..949c3d4
--- /dev/null
+++ b/sem4/embedded/m6/m6.ino
@@ -0,0 +1,67 @@
+#include <krnl.h>
+#define STACK 100
+#define BUTTONPIN 2
+#define LEDPIN 13
+
+char stk1[STACK];
+struct k_t *tsk1;
+struct k_msg_t *pmsg;
+char msgbuff[10];
+
+ISR(INT0_vect) {
+    static unsigned long last = 0;
+
+    unsigned long now = millis();
+    if (now - last < 100) {
+        return;
+    }
+    last = now;
+
+    static char state = 0;
+    state = !state;
+
+    ki_send(pmsg, (void *)&state);
+
+}
+
+void f1() {
+    while(true) {
+        char state;
+        int lost;
+        if (k_receive(pmsg, &state, 0, &lost) < 0) {
+            continue;
+        }
+
+        //k_eat_msec_time(1000);
+
+        Serial.print("Lost: "); Serial.println(lost);
+
+        digitalWrite(LEDPIN, state);
+    }
+}
+
+void setup()
+{
+    pinMode(LEDPIN, OUTPUT);
+
+	pinMode(BUTTONPIN, INPUT_PULLUP);
+	// Enable interrupt 0
+	EIMSK |= 1 << INT0;
+	// Eable on rising edge
+	EICRA |= (1 << ISC01);
+
+    Serial.begin(115200);
+    Serial.println("Starting");
+
+    k_init(1, 0, 1);
+
+    pmsg = k_crt_send_Q(10, 1, msgbuff);
+    tsk1 = k_crt_task(f1, 10, stk1, STACK);
+
+    k_start(1);
+}
+
+void loop()
+{
+
+}