Encoder: Move handling encoder events to main

firmware/src/encoder.cpp

@@ -1,6 +1,7 @@
 #include <Arduino.h>
 
 #include "constants.h"
+#include "encoder.h"
 
 /*
 
@@ -12,21 +13,72 @@ When rotated clockwise, CLK changes before DT; when rotated counter-clockwise, D
 
 */
 
+#define SW_DEBOUNCE_MS 10
+
+bool previousClk = false;
+bool previousDt = false;
+
 void setupEncoder() {
   pinMode(CLK_PIN, INPUT);
   pinMode(DT_PIN, INPUT);
   pinMode(SW_PIN, INPUT_PULLUP);
+
+  // save initial state
+  previousClk = digitalRead(CLK_PIN);
+  previousDt = digitalRead(DT_PIN);
 }
 
-void demoEncoder() {
+bool previousPressed = false;
+unsigned long lastChangeAt = 0;
+
+SwitchEvent handleSwitch() {
+  bool isPressed = !digitalRead(SW_PIN);
+
+  // only handle change
+  if (isPressed == previousPressed) {
+    return SWITCH_NONE;
+  }
+
+  // debounce
+  unsigned long now = millis();
+  if (now - lastChangeAt < SW_DEBOUNCE_MS) {
+    return SWITCH_NONE;
+  }
+
+  // save state
+  previousPressed = isPressed;
+  lastChangeAt = now;
+
+  // return event
+  return isPressed ? SWITCH_PRESSED : SWITCH_RELEASED;
+}
+
+EncoderEvent handleEncoder() {
   bool clk = digitalRead(CLK_PIN);
   bool dt = digitalRead(DT_PIN);
-  bool sw = digitalRead(SW_PIN);
 
-  Serial.print("CLK: ");
-  Serial.print(clk);
-  Serial.print(" DT: ");
-  Serial.print(dt);
-  Serial.print(" SW: ");
-  Serial.println(sw);
+  // only handle change
+  if (clk == previousClk && dt == previousDt) {
+    return ENCODER_NONE;
+  }
+
+  // TODO: Do we need to debounce encoder?
+
+  // clockwise pattern:
+  // clk: 1001 1001
+  // dt:  1100 1100
+  // counter-clockwise pattern:
+  // clk: 1100 1100
+  // dt:  1001 1001
+  EncoderEvent event = ENCODER_NONE;
+  if (clk == dt) {
+    event = clk == previousClk ? ENCODER_CLOCKWISE : ENCODER_COUNTER_CLOCKWISE;
+  }
+
+  // save state
+  previousClk = clk;
+  previousDt = dt;
+
+  // return event
+  return event;
 }

firmware/src/encoder.h

@@ -1,4 +1,16 @@
 #pragma once
 
+typedef uint8_t SwitchEvent;
+#define SWITCH_NONE 0
+#define SWITCH_PRESSED 1
+#define SWITCH_RELEASED 2
+
+typedef int8_t EncoderEvent;
+#define ENCODER_NONE 0
+#define ENCODER_CLOCKWISE 1
+#define ENCODER_COUNTER_CLOCKWISE -1
+
 void setupEncoder();
-void demoEncoder();
+
+SwitchEvent handleSwitch();
+EncoderEvent handleEncoder();

firmware/src/keyboard.cpp

@@ -2,9 +2,34 @@
 #include <Wire.h>
 
 #include "constants.h"
+#include "debug.h"
 
 PCF8574 kbd(KBD_I2C_ADDR, &Wire);
 
+/*
+  Keyboard layout:
+
+row/col 0 1 2 3
+
+  0     1 2 3 A
+  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,
+    7, 8, 9, KEY_NONE,
+    KEY_NONE, 0, KEY_NONE, KEY_NONE};
+
 bool setupKeyboard() {
   if (!kbd.begin()) {
     Serial.println("Could not initialize keyboard");
@@ -18,10 +43,74 @@ bool setupKeyboard() {
   return true;
 }
 
+Key getPressedKey();
+uint8_t getPressedDigit(Key key);
+
+#define KBD_COL_MASK 0b11110000
+#define KBD_ROW_MASK 0b00001111
+
 void demoKeyboard() {
-  kbd.write8(0b11110000); // first 4 bits are columns, low when pressed
-  // kbd.write8(0b00001111); // last 4 bits are rows, low when pressed
-  int x = kbd.read8();
-  Serial.print("Keyboard: ");
-  Serial.println(x, BIN);
+  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
+ *
+ * NOTE: Only one key can be pressed at a time;
+ * if multiple keys are pressed, the result is undefined
+ */
+Key getPressedKey() {
+  // check pressed column
+  // first 4 bits are columns, low when pressed
+  kbd.write8(KBD_COL_MASK);
+
+  uint8_t cols = kbd.read8();
+  if (cols == KBD_COL_MASK) {
+    return KEY_NONE;
+  }
+
+  uint8_t colState = ~(cols >> 4);
+  uint8_t colPressed = 0;
+  if (colState & 0b1000) colPressed = 0;
+  else if (colState & 0b0100) colPressed = 1;
+  else if (colState & 0b0010) colPressed = 2;
+  else if (colState & 0b0001) colPressed = 3;
+  else fatal();
+
+  // check pressed row
+  // last 4 bits are rows, low when pressed
+  kbd.write8(KBD_ROW_MASK);
+
+  uint8_t rowState = ~kbd.read8();
+  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();
+
+  // 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/main.cpp

@@ -22,12 +22,19 @@ void setup() {
 }
 
 void loop() {
-  tick();
+  // tick();
 
-  debugScanI2C();
-  demoScreen();
+  // debugScanI2C();
+  // demoScreen();
   // demoKeyboard();
-  // demoEncoder();
 
-  delay(200);
+  if (auto event = handleSwitch()) {
+    tick();
+    Serial.println(event == SWITCH_PRESSED ? "Pressed" : "Released");
+  }
+
+  if (auto event = handleEncoder()) {
+    tick();
+    Serial.println(event == ENCODER_CLOCKWISE ? "Clockwise" : "Counter-clockwise");
+  }
 }