Encoder: Add debounce

firmware/src/buzzer.cpp

@@ -2,19 +2,12 @@
 #include "constants.h"
 #include <Arduino.h>
 
-void buzzOff() {
-  noTone(BUZZER_PIN);
-  pinMode(BUZZER_PIN, INPUT);
-}
-
 void helloBuzz() {
   tone(BUZZER_PIN, 500, 100);
   delay(100);
   tone(BUZZER_PIN, 1000, 100);
   delay(100);
   tone(BUZZER_PIN, 4000, 100);
-  delay(100);
-  buzzOff();
 }
 
 void happyBuzz() {
@@ -22,23 +15,18 @@ void happyBuzz() {
   delay(75);
   tone(BUZZER_PIN, 2000, 100);
   delay(100);
-  buzzOff();
 }
 
 void sadBuzz() {
   tone(BUZZER_PIN, 330, 250);
   delay(300);
   tone(BUZZER_PIN, 311, 250);
-  delay(250);
-  buzzOff();
 }
 
 void beep() {
   tone(BUZZER_PIN, 1000, 50);
-  delay(50);
-  buzzOff();
 }
 
 void tick() {
-  tone(BUZZER_PIN, 200, 5);
+  tone(BUZZER_PIN, 200, 10);
 }

firmware/src/buzzer.h

@@ -4,5 +4,4 @@ void helloBuzz();
 void happyBuzz();
 void sadBuzz();
 void beep();
-void buzzOff();
 void tick();

firmware/src/constants.h

@@ -24,3 +24,12 @@
 // --- Keyboard config
 
 #define KBD_I2C_ADDR 0x21
+
+// Used by keyboard and encoder switch
+#define DEBOUNCE_MS 10
+
+// --- Z axis motor
+
+#define STEPPER_ENABLE 8
+#define STEPPER_DIR 9
+#define STEPPER_STEP 10

firmware/src/encoder.cpp

@@ -13,8 +13,6 @@ When rotated clockwise, CLK changes before DT; when rotated counter-clockwise, D
 
 */
 
-#define SW_DEBOUNCE_MS 10
-
 bool previousClk = false;
 bool previousDt = false;
 
@@ -40,8 +38,8 @@ SwitchEvent handleSwitch() {
   }
 
   // debounce
-  unsigned long now = millis();
-  if (now - lastChangeAt < SW_DEBOUNCE_MS) {
+  auto now = millis();
+  if (now - lastChangeAt < DEBOUNCE_MS) {
     return SWITCH_NONE;
   }
 
@@ -53,6 +51,8 @@ SwitchEvent handleSwitch() {
   return isPressed ? SWITCH_PRESSED : SWITCH_RELEASED;
 }
 
+unsigned long lastEncoderChangeAt = 0;
+
 EncoderEvent handleEncoder() {
   bool clk = digitalRead(CLK_PIN);
   bool dt = digitalRead(DT_PIN);
@@ -62,7 +62,11 @@ EncoderEvent handleEncoder() {
     return ENCODER_NONE;
   }
 
-  // TODO: Do we need to debounce encoder?
+  // debounce
+  auto now = millis();
+  if (now - lastEncoderChangeAt < DEBOUNCE_MS) {
+    return SWITCH_NONE;
+  }
 
   // clockwise pattern:
   // clk: 1001 1001
@@ -78,6 +82,7 @@ EncoderEvent handleEncoder() {
   // save state
   previousClk = clk;
   previousDt = dt;
+  lastEncoderChangeAt = now;
 
   // return event
   return event;

firmware/src/keyboard.cpp

@@ -3,6 +3,8 @@
 
 #include "constants.h"
 #include "debug.h"
+#include "buzzer.h"
+#include "keyboard.h"
 
 PCF8574 kbd(KBD_I2C_ADDR, &Wire);
 
@@ -15,15 +17,10 @@ row/col 0 1 2 3
   1     4 5 6 B
   2     7 8 9 C
   3     * 0 # D
-
-  Keys, in order:
-  123A 456B 789C *0#D
 */
 
-typedef uint8_t Key;
-
 const char *allKeys = "123A456B789C*0#D";
-#define KEY_NONE 255
+
 const uint8_t digits[16] =
   { 1, 2, 3, KEY_NONE,
     4, 5, 6, KEY_NONE,
@@ -43,30 +40,35 @@ bool setupKeyboard() {
   return true;
 }
 
+Key previousKey = KEY_NONE;
+unsigned long lastPressedAt = 0;
+
 Key getPressedKey();
-uint8_t getPressedDigit(Key key);
+Key handleKeyboard() {
+  auto key = getPressedKey();
+
+  // only handle change
+  if (key == previousKey) {
+    return KEY_NONE;
+  }
+
+  // debounce
+  auto now = millis();
+  if (now - lastPressedAt < DEBOUNCE_MS) {
+    return KEY_NONE;
+  }
+
+  // save state
+  previousKey = key;
+  lastPressedAt = now;
+
+  // return event
+  return key;
+}
 
 #define KBD_COL_MASK 0b11110000
 #define KBD_ROW_MASK 0b00001111
 
-void demoKeyboard() {
-  auto key = getPressedKey();
-  if (key != KEY_NONE) {
-    Serial.print("Key pressed: ");
-    Serial.print(allKeys[key]);
-
-    auto digit = getPressedDigit(key);
-    if (digit != KEY_NONE) {
-      Serial.print(", digit: ");
-      Serial.print(digit);
-    } else {
-      Serial.print(" (Not a digit)");
-    }
-
-    Serial.println();
-  }
-}
-
 /**
  * Returns pressed key or KEY_NONE if no key is pressed
  *
@@ -89,27 +91,40 @@ Key getPressedKey() {
   else if (colState & 0b0100) colPressed = 1;
   else if (colState & 0b0010) colPressed = 2;
   else if (colState & 0b0001) colPressed = 3;
-  else fatal();
+  else {
+    Serial.print("Invalid kbd column state: ");
+    Serial.println(cols, BIN);
+    sadBuzz();
+    return KEY_NONE;
+  }
 
   // check pressed row
   // last 4 bits are rows, low when pressed
   kbd.write8(KBD_ROW_MASK);
 
-  uint8_t rowState = ~kbd.read8();
+  uint8_t rows = kbd.read8();
+  if (rows == KBD_ROW_MASK) {
+    // between col and row read, a key could be released
+    return KEY_NONE;
+  }
+
+  uint8_t rowState = ~rows;
   uint8_t rowPressed = 0;
   if (rowState & 0b1000) rowPressed = 0;
   else if (rowState & 0b0100) rowPressed = 1;
   else if (rowState & 0b0010) rowPressed = 2;
   else if (rowState & 0b0001) rowPressed = 3;
-  else fatal();
+  else {
+    Serial.print("Invalid kbd row state: ");
+    Serial.println(rowState, BIN);
+    sadBuzz();
+    return KEY_NONE;
+  }
 
   // return key
   return (rowPressed * 4) + colPressed;
 }
 
-/**
- * Returns pressed digit or KEY_NONE if the key is not a digit
- */
 uint8_t getPressedDigit(Key key) {
   if (key == KEY_NONE) return KEY_NONE;
   return digits[key];

firmware/src/keyboard.h

@@ -1,4 +1,32 @@
 #pragma once
 
+/*
+  Keys, in order:
+  123A 456B 789C *0#D
+ */
+typedef uint8_t Key;
+#define KEY_NONE 255
+#define KEY_A 3
+#define KEY_B 7
+#define KEY_C 11
+#define KEY_D 15
+#define KEY_ASTERISK 12
+#define KEY_HASH 14
+
+extern const char *allKeys;
+
 bool setupKeyboard();
-void demoKeyboard();
+
+/**
+ * Returns pressed key once upon its release
+ * or KEY_NONE if no key is pressed
+ *
+ * NOTE: Only one key can be pressed at a time;
+ * if multiple keys are pressed, the behavior is undefined
+ */
+Key handleKeyboard();
+
+/**
+ * Returns pressed digit or KEY_NONE if the key is not a digit
+ */
+uint8_t getPressedDigit(Key key);

firmware/src/main.cpp

@@ -7,10 +7,14 @@
 #include "keyboard.h"
 #include "encoder.h"
 #include "debug.h"
+#include "timer.h"
+#include "stepper.h"
 
 void setup() {
   setupDebug();
   setupEncoder();
+  setupTimer();
+  setupStepper();
 
   Wire.begin();
 
@@ -22,11 +26,39 @@ void setup() {
 }
 
 void loop() {
-  // tick();
-
   // debugScanI2C();
   // demoScreen();
-  // demoKeyboard();
+  // demoStepper();
+
+  demoTimer();
+
+  auto key = handleKeyboard();
+  if (key != KEY_NONE) {
+    Serial.print("Key pressed: ");
+    Serial.print(allKeys[key]);
+
+    auto digit = getPressedDigit(key);
+    if (digit != KEY_NONE) {
+      Serial.print(", digit: ");
+      Serial.print(digit);
+    } else {
+      Serial.print(" (Not a digit)");
+    }
+
+    Serial.println();
+
+    if (key == KEY_A) {
+      happyBuzz();
+    } else if (key == KEY_B) {
+      sadBuzz();
+    } else if (key == KEY_C) {
+      beep();
+    } else if (key == KEY_D) {
+      tick();
+    } else {
+      tick();
+    }
+  }
 
   if (auto event = handleSwitch()) {
     tick();

firmware/src/stepper.cpp

@@ -0,0 +1,25 @@
+#include <Arduino.h>
+#include "constants.h"
+
+void setupStepper() {
+  pinMode(STEPPER_ENABLE, OUTPUT);
+  pinMode(STEPPER_DIR, OUTPUT);
+  pinMode(STEPPER_STEP, OUTPUT);
+
+  // low = enabled
+  digitalWrite(STEPPER_ENABLE, LOW);
+}
+
+bool stepperDir = HIGH;
+
+void demoStepper() {
+  Serial.println("Demoing stepper motor - rotating 200 steps");
+  stepperDir = !stepperDir;
+  digitalWrite(STEPPER_DIR, stepperDir);
+  for (int i = 0; i < 200; i++) {
+    digitalWrite(STEPPER_STEP, HIGH);
+    delay(2);
+    digitalWrite(STEPPER_STEP, LOW);
+    delay(7);
+  }
+}

firmware/src/stepper.h

@@ -0,0 +1,4 @@
+#pragma once
+
+void setupStepper();
+void demoStepper();

firmware/src/timer.cpp

@@ -0,0 +1,46 @@
+#include <Arduino.h>
+
+#define DEMO_TRIGGER_MS 1500
+
+void setupTimer() {
+  // Set up Timer 0 to trigger interrupt every 1ms
+  // Timer 0 is already used and configured by Arduino for millis()
+  // however it uses TOIE0 (overflow interrupt), so we'll use OCIE0A:
+  //   When this bit is written to one, and the I-flag in the Status Register is set
+  //   (interrupts globally enabled), the Timer/Counter0 Output Compare A Match interrupt is enabled
+  //   The corresponding Interrupt Vector is executed when the OCF0A Flag, located in TIFR0, is set.
+  OCR0A = 0xAF; // any number is OK, it will trigger at some point during the counter
+  TIMSK0 |= _BV(OCIE0A);
+}
+
+// incremented every DEMO_TRIGGER_MS by interrupt,
+// read and decremented by main loop
+volatile uint8_t timerEvents = 0;
+
+void demoTimer() {
+  bool shouldTrigger = false;
+
+  noInterrupts();
+  if (timerEvents > 0) {
+    timerEvents--;
+    shouldTrigger = true;
+  }
+  interrupts();
+
+  if (shouldTrigger) {
+    Serial.println("Timer tick!");
+  }
+}
+
+volatile uint16_t timerMillis = 0;
+
+// triggers every 1ms
+ISR(TIMER0_COMPA_vect) {
+  timerMillis++;
+  if (timerMillis >= DEMO_TRIGGER_MS) {
+    timerMillis -= DEMO_TRIGGER_MS;
+    timerEvents++;
+  }
+
+  // TODO: Add motor encoder reading, calculate required carriage offset, control stepper
+}

firmware/src/timer.h

@@ -0,0 +1,2 @@
+void setupTimer();
+void demoTimer();