refactor code

clock/README.md

@@ -36,8 +36,8 @@ States:
 
 - Rate CV input
 - Less jittery timer
-
-- Faster speeds for sequencers? Negative subdivisions?
+- Get working on bare ATMega328p
+- Faster speeds with negative subdivisions
 
 https://en.wikipedia.org/wiki/Swing_(jazz_performance_style)
 https://github.com/adafruit/TinyWireM/blob/master/USI_TWI_Master.h

clock/src/Button.h

@@ -1,4 +1,5 @@
 #pragma once
+
 #include <Arduino.h>
 
 // A push-button toggle switch. Supports debouncing.

clock/src/Display.h

@@ -1,4 +1,5 @@
 #pragma once
+
 #include "SevenSegment.h"
 
 // given a number, get the character at index `digit`
@@ -23,71 +24,92 @@ char getDigit(int16_t value, size_t digit)
   return '0' + value;
 }
 
-// A set of 7-segment displays.
-// Expects
+// An array of 7-segment displays.
+// Uses the same digit control port but only addresses one at a time,
+// round robbin. This means the more segments there are the worse
+// the brightness will be. Must call `tick` on a tight loop to
+// switch the digit displayed or else the display will clearly flicker.
+// Number of segments must be a compile time constant through `DIGITS`
+// template.
+// Displays signed 16-bit numbers.
 template <size_t DIGITS>
 class Display
 {
 private:
-  SevenSegment _digits[DIGITS];
-  size_t _index = 0;
+  SevenSegment _digits[DIGITS]; // LSB first
+  size_t _index = 0;            // which segment is currently addressed
   char _contents[DIGITS];
 
 public:
-  void begin(volatile uint8_t* segmentPort, uint8_t* ctrlPins)
+  void begin(uint8_t portNumber, uint8_t *ctrlPins)
   {
-    for(size_t i = 0; i < DIGITS; i++) {
-      _digits[i].begin(ctrlPins[i], segmentPort);
-      _contents[i] = ' ';
+    for (size_t i = 0; i < DIGITS; i++)
+    {
+      _digits[i].begin(portNumber, ctrlPins[i]);
+      setChar(i, ' ');
     }
     _index = 0;
   }
 
+  // set all the displays to blank
   void clear()
   {
-    for (size_t i = 0; i < DIGITS; i++) {
-      _contents[i] = ' ';
+    for (size_t i = 0; i < DIGITS; i++)
+    {
+      setChar(i, ' ');
     }
   }
 
-  void tick() {
+  // update which display is showing
+  void tick()
+  {
     _digits[_index].turnOff();
     _index = (_index + 1) % DIGITS;
     _digits[_index].display(_contents[_index]);
     _digits[_index].turnOn();
   }
 
-  void setChar(size_t i, char c) {
-    if (i < DIGITS) {
+  void setChar(size_t i, char c)
+  {
+    if (i < DIGITS)
+    {
       _contents[i] = c;
     }
   }
 
+  // display a signed number on the
   void displayNumber(int16_t number)
   {
-    for (size_t i = 0; i < DIGITS; i++) {
-      _contents[i] = getDigit(number, i);
+    for (size_t i = 0; i < DIGITS; i++)
+    {
+      setChar(i, getDigit(number, i));
     }
   }
 
+  // light up all segments (all 8's)
   void displayReset()
   {
-    for (size_t i = 0; i < DIGITS; i++) {
-      _contents[i] = '0';
+    for (size_t i = 0; i < DIGITS; i++)
+    {
+      setChar(i, '8');
     }
   }
 
-  void blinkReset()
+  // blink the reset a few times.
+  // NOTE: blocking, will return after `blinkCount * 2 * blinkTime` milliseconds.
+  void blinkReset(size_t blinkCount = 3, uint8_t blinkTime = 50)
   {
-    for (size_t i = 0; i < 3; i++)
+    for (size_t i = 0; i < blinkCount; i++)
     {
       clear();
-      for (size_t i = 0; i < 50; i++) {
+      for (size_t i = 0; i < blinkTime; i++)
+      {
         tick();
         delay(1);
       }
       displayReset();
-      for (size_t i = 0; i < 50; i++) {
+      for (size_t i = 0; i < blinkTime; i++)
+      {
         tick();
         delay(1);
       }

clock/src/Knob.h

@@ -1,4 +1,5 @@
 #pragma once
+
 #include <Arduino.h>
 
 // A continuous rotary switch with evenly-valued resistors between each

clock/src/SevenSegment.h

@@ -1,60 +1,83 @@
 #pragma once
+
 #include <Arduino.h>
 
 #define CHAR_BLANK 0b00000000
 #define CHAR_MINUS 0b00000010
+#define CHAR_UNDERSCORE 0b00001000
 
+// TODO: would switch be faster than
+// array index?
 const uint8_t LETTERS[] = {
-  // ABCDEGF
-  0b01111101,
-  0b00110000,
-  0b01101110,
-  0b01111010,
-  0b00110011,
-  0b01011011,
-  0b01011111,
-  0b01110000,
-  0b01111111,
-  0b01111011,
+    //_ABCDEGF
+    0b01111101,
+    0b00110000,
+    0b01101110,
+    0b01111010,
+    0b00110011,
+    0b01011011,
+    0b01011111,
+    0b01110000,
+    0b01111111,
+    0b01111011,
 };
 
-class SevenSegment {
-  private:
-    uint8_t _controlPin;
-    volatile uint8_t* _segmentPort;
-
-  public:
-    // NOTE: its up to the caller to set the segmentPort to an
-    // output since we don't know which registers to use
-    void begin(uint8_t controlPin, volatile uint8_t* segmentPort) {
-      _controlPin = controlPin;
-      _segmentPort = segmentPort;
-      pinMode(controlPin, OUTPUT);
-      turnOff();
-    }
+// Addresses a common-cathode 7-segment display without a
+// decimal.
+// Assumes ABCDEGF segments are connected to pins 0-6 of
+// a AVR port for faster addressing.
+// The control pin should be connected to the common cathode.
+// It is pulled low to turn on the LEDs.
+class SevenSegment
+{
+private:
+  uint8_t _controlPin;
+  volatile uint8_t *_segmentPort;
 
-    void turnOff() {
-      digitalWrite(_controlPin, HIGH);
-    }
+public:
+  void begin(uint8_t portNumber, uint8_t controlPin)
+  {
+    _controlPin = controlPin;
+    _segmentPort = portOutputRegister(portNumber);
+    pinMode(controlPin, OUTPUT);
+    volatile uint8_t *portModeRegister = portModeRegister(portNumber);
+    *portModeRegister = 0x7F;
+    turnOff();
+  }
 
-    void turnOn() {
-      digitalWrite(_controlPin, LOW);
-    }
+  void turnOff()
+  {
+    digitalWrite(_controlPin, HIGH);
+  }
 
-    bool display(char c) {
-      if (c >= '0' && c <= '9') {
-        *_segmentPort = LETTERS[c - '0'];
-        return true;
-      }
-      if (c == ' ')   {
-        *_segmentPort = CHAR_BLANK;
-        return true;
-      }
-      if (c == '-')   {
-        *_segmentPort = CHAR_MINUS;
-        return true;
-      }
-      // unsupported char
-      return false;
+  void turnOn()
+  {
+    digitalWrite(_controlPin, LOW);
+  }
+
+  bool display(char c)
+  {
+    if (c >= '0' && c <= '9')
+    {
+      *_segmentPort = LETTERS[c - '0'];
+      return true;
+    }
+    if (c == ' ')
+    {
+      *_segmentPort = CHAR_BLANK;
+      return true;
+    }
+    if (c == '-')
+    {
+      *_segmentPort = CHAR_MINUS;
+      return true;
+    }
+    if (c == '_')
+    {
+      *_segmentPort = CHAR_UNDERSCORE;
+      return true;
     }
+    // unsupported char
+    return false;
+  }
 };

clock/src/TapTempo.h

@@ -1,4 +1,5 @@
 #pragma once
+
 #include <Arduino.h>
 
 #define NO_TEMPO 0