Fixed character output

Added placeholders for centered/right-aligned text
Added text mode toggle for testing purposes
Added serial debug option

NerfStatTrek.ino

@@ -1,11 +1,18 @@
 #include "SegmentDisplay.h"
 
+#define ASCIIUppercaseA 65
+#define ASCIIUppercaseZ 90
+
 SegmentDisplay* display;
 
+char* text = new char[7];
+
+
 void setup()
 {
+  pinMode(2, INPUT_PULLUP);
   pinMode(A3, INPUT);
-  
+
   display = new SegmentDisplay();
   //display->setClockSpeed(4000000UL);
   display->setClockPin(12);
@@ -13,6 +20,14 @@ void setup()
   display->setLatchPin(10);
   display->setDigits(6);
   display->begin();
+
+  text[0] = '\0';
+  text[1] = '\0';
+  text[2] = '\0';
+  text[3] = '\0';
+  text[4] = '\0';
+  text[5] = '\0';
+  text[6] = '\0';
 }
 
 unsigned long currentTime;
@@ -20,21 +35,76 @@ unsigned long lastCounterTime = 0;
 uint32_t counter = 0;
 uint32_t delayValue;
 
+bool showChars = true;
+byte character = ASCIIUppercaseA - 1;
+
+int buttonValue;
+bool buttonDown = false;
+unsigned long lastButtonChange = 0;
+
+
+
 void loop()
 {
   currentTime = millis();
 
-  if (currentTime - lastCounterTime > 100UL)
+  buttonValue = digitalRead(2);
+  if (buttonValue == LOW)
   {
-    counter++;
-    if (counter > 999999)
-      counter = 0;
-
-    lastCounterTime = currentTime;
-
-    delayValue = ((uint32_t)analogRead(A3) * 100);
-    display->setDigitDelayMicroseconds(delayValue);
+    if (!buttonDown && (currentTime - lastButtonChange) > 50)
+    {
+      buttonDown = true;
+      showChars = !showChars;
+      lastButtonChange = currentTime;
+    }
+  }
+  else
+  {
+    if (buttonDown && (currentTime - lastButtonChange) > 50)
+    {
+      buttonDown = false;
+      lastButtonChange = currentTime;
+    }
   }
 
-  display->writeNumber(counter);
+  if (showChars)
+  {
+    if (lastCounterTime == 0 || currentTime - lastCounterTime > 250UL)
+    {
+      character++;
+      if (character > ASCIIUppercaseZ)
+        character = ASCIIUppercaseA;
+
+      lastCounterTime = currentTime;
+
+      delayValue = ((uint32_t)analogRead(A3) * 100);
+      display->setDigitDelayMicroseconds(delayValue);
+    }
+
+    for (byte c = 0; c < 6; c++)
+    {
+      if (character + c > ASCIIUppercaseZ)
+        text[c] = ' ';
+      else
+        text[c] = character + c;
+    }
+
+    display->writeTextLeft(text);
+  }
+  else
+  {
+    if (currentTime - lastCounterTime > 100UL)
+    {
+      counter++;
+      if (counter > 999999)
+        counter = 0;
+
+      lastCounterTime = currentTime;
+
+      delayValue = ((uint32_t)analogRead(A3) * 100);
+      display->setDigitDelayMicroseconds(delayValue);
+    }
+
+    display->writeNumber(counter);
+  }
 }

SegmentDisplay.cpp

@@ -23,6 +23,11 @@ void SegmentDisplay::begin()
   #if defined(SDUseSPI)
   SPI.begin();
   #endif
+
+  #if defined(SDSerialDebug)
+  Serial.begin(9600);
+  Serial.print("SegmentDisplay::begin\n");
+  #endif
 }
 
 
@@ -36,6 +41,11 @@ void SegmentDisplay::end()
 
 void SegmentDisplay::writeNumber(uint32_t value)
 {
+  #if defined(SDSerialDebug)
+  String textValue = String(value);
+  Serial.print("SegmentDisplay::writeNumber: " + textValue + "\n");
+  #endif
+
   byte digitMask = 1;
 
   for (byte digit = digits; digit > 0; digit--)
@@ -48,96 +58,113 @@ void SegmentDisplay::writeNumber(uint32_t value)
 }
 
 
-#define ASCIIZero 48
-#define ASCIINine 57
-#define ASCIIUppercaseA 65
-#define ASCIIUppercaseZ 90
-#define ASCIILowercaseA 97
-#define ASCIILowercaseZ 122
-
-
-void SegmentDisplay::writeText(char* value)
+void SegmentDisplay::writeTextLeft(char* value)
 {
-  byte digitMask = 1;
-  byte digit = digits;
-  byte charValue;
+  #if defined(SDSerialDebug)
+  Serial.print("SegmentDisplay::writeTextLeft: " + value + "\n");
+  #endif
 
-  while (digit > 0 && value != '\0')
+  byte digitMask = 1 << (digits - 1);
+  byte charIndex = 0;
+
+  while (charIndex < digits && value[charIndex] != '\0')
   {
-    charValue = *value;
+    writeChar(value[charIndex], digitMask);
 
-    // Lowercase
-    if (charValue >= ASCIILowercaseA && charValue <= ASCIILowercaseZ)
-      writeDisplay(pgm_read_byte_near(SDCharacterSegments + (charValue - ASCIILowercaseA)), digitMask);
-
-    // Uppercase
-    else if  (charValue >= ASCIIUppercaseA && charValue <= ASCIIUppercaseZ)
-      writeDisplay(pgm_read_byte_near(SDCharacterSegments + (charValue - ASCIIUppercaseA)), digitMask);
-
-    // Numbers
-    else if (charValue >= ASCIIZero && charValue <= ASCIINine)
-      writeDisplay(pgm_read_byte_near(SDNumberSegments + (charValue - ASCIIZero)), digitMask);
-
-    // Space / unknown
-    else
-      writeDisplay(0, digitMask);
-
-    digit--;
-    digitMask <<= 1;
-    value++;
+    digitMask >>= 1;
+    charIndex++;
   }
 
-  while (digit > 0)
+  while (charIndex < digits)
   {
     writeDisplay(0, digitMask);
-
-    digit--;
-    digitMask <<= 1;
+    digitMask >>= 1;
+    charIndex++;
   }
 }
 
 
+void SegmentDisplay::writeTextCenter(char* value)
+{
+}
+
+
+void SegmentDisplay::writeTextRight(char* value)
+{
+}
+
+
 inline void SegmentDisplay::writeDigit(byte value, byte digitMask)
 {
   writeDisplay(pgm_read_byte_near(SDNumberSegments + value), digitMask);
+}
 
-  if (digitDelayMicroseconds > 1000)
+
+inline void SegmentDisplay::writeChar(char value, byte digitMask)
+{
+  // Lowercase
+  if (value >= ASCIILowercaseA && value <= ASCIILowercaseZ)
+    writeDisplay(pgm_read_byte_near(SDCharacterSegments + (value - ASCIILowercaseA)), digitMask);
+
+  // Uppercase
+  else if  (value >= ASCIIUppercaseA && value <= ASCIIUppercaseZ)
+    writeDisplay(pgm_read_byte_near(SDCharacterSegments + (value - ASCIIUppercaseA)), digitMask);
+
+  // Numbers
+  else if (value >= ASCIIZero && value <= ASCIINine)
+    writeDisplay(pgm_read_byte_near(SDNumberSegments + (value - ASCIIZero)), digitMask);
+
+  // Space / unknown
+  else
+    writeDisplay(0, digitMask);
+}
+
+
+inline void SegmentDisplay::writeDisplay(byte segmentMask, byte digitMask)
+{
+  // If no segments should be lit, clear the digit mask as well to prevent
+  // power leaking through (it's probably an issue in my circuit or with the
+  // specific displays I used, but it still makes sense to close both sides).
+  //
+  // Still push out the zeros though, if we don't the display will vary
+  // in brightness depending on what's on it.
+  if (segmentMask == 0)
+    digitMask = 0;
+
+  #if defined(SDSerialDebug)
+  String segmentValue = String(segmentMask);
+  String digitValue = String(digitMask);
+
+  Serial.print("SegmentDisplay::writeDisplay: " + segmentValue + " " + digitValue + "\n");
+  #endif
+
+  #if defined(SDUseSPI)
+    SPI.beginTransaction(SPISettings(clockSpeed, MSBFIRST, SPI_MODE0));
+    #if defined(SDPushSegmentsFirst)
+    SPI.transfer(segmentMask);
+    SPI.transfer(digitMask);
+    #else
+    SPI.transfer(digitMask);
+    SPI.transfer(segmentMask);
+    #endif
+    SPI.endTransaction();
+  #else
+    #if defined(SDPushSegmentsFirst)
+    shiftOut(dataPin, clockPin, MSBFIRST, segmentMask);
+    shiftOut(dataPin, clockPin, MSBFIRST, digitMask);
+    #else
+    shiftOut(dataPin, clockPin, MSBFIRST, digitMask);
+    shiftOut(dataPin, clockPin, MSBFIRST, segmentMask);
+    #endif
+
+    digitalWrite(latchPin, HIGH);
+    digitalWrite(latchPin, LOW);
+  #endif
+
+  #if defined(SPHandleLargeDelays)
+  if (digitDelayMicroseconds > 15000)
     delay(digitDelayMicroseconds / 1000);
   else
+  #endif
     delayMicroseconds(digitDelayMicroseconds);
 }
-
-
-#if defined(SDUseSPI)
-
-inline void SegmentDisplay::writeDisplay(byte segmentMask, byte digitMask)
-{
-  SPI.beginTransaction(SPISettings(clockSpeed, MSBFIRST, SPI_MODE0));
-  #if defined(SDPushSegmentsFirst)
-  SPI.transfer(segmentMask);
-  SPI.transfer(digitMask);
-  #else
-  SPI.transfer(digitMask);
-  SPI.transfer(segmentMask);
-  #endif
-  SPI.endTransaction();
-}
-
-#else
-
-inline void SegmentDisplay::writeDisplay(byte segmentMask, byte digitMask)
-{
-  digitalWrite(latchPin, LOW);
-
-  #if defined(SDPushSegmentsFirst)
-  shiftOut(dataPin, clockPin, MSBFIRST, segmentMask);
-  shiftOut(dataPin, clockPin, MSBFIRST, digitMask);
-  #else
-  shiftOut(dataPin, clockPin, MSBFIRST, digitMask);
-  shiftOut(dataPin, clockPin, MSBFIRST, segmentMask);
-  #endif
-
-  digitalWrite(latchPin, HIGH);
-}
-
-#endif

SegmentDisplay.h

@@ -29,7 +29,9 @@ class SegmentDisplay
     void end();
 
     void writeNumber(uint32_t value);
-    void writeText(char* value);
+    void writeTextLeft(char* value);
+    void writeTextCenter(char* value);
+    void writeTextRight(char* value);
 
     byte getDigits() { return digits; }
     void setDigits(byte value) { digits = value; }
@@ -55,6 +57,8 @@ class SegmentDisplay
 
   protected:
     void writeDigit(byte value, byte digitMask);
+    void writeChar(char value, byte digitMask);
+  public:
     void writeDisplay(byte characterMask, byte digitMask);
 
   private:

SegmentDisplayChars.h

@@ -13,6 +13,14 @@
 #define SegmentG 64 // Middle
 
 
+#define ASCIIZero 48
+#define ASCIINine 57
+#define ASCIIUppercaseA 65
+#define ASCIIUppercaseZ 90
+#define ASCIILowercaseA 97
+#define ASCIILowercaseZ 122
+
+
 const byte SDNumberSegments[10] PROGMEM =
 {
   /**
@@ -162,7 +170,7 @@ const byte SDCharacterSegments[26] PROGMEM =
    * | |
    *
   **/
-  SegmentB | SegmentC | SegmentD | SegmentF | SegmentG,
+  SegmentB | SegmentC | SegmentE | SegmentF | SegmentG,
 
   /**
    *

SegmentDisplayConfig.h

@@ -23,4 +23,28 @@
 **/
 //#define SDPushSegmentsFirst
 
+
+/**
+ * Support large digit delays (> 15000 microseconds)
+ *
+ * If not defined, delayMicroseconds() will always be used,
+ * which is currently only accurate up to 16383, but it saves
+ * the cost of checking the value.
+ *
+ * If you want to delay the digits further, most likely
+ * for multiplexing demonstration purposes only, enable this
+ * to automatically fall back to delay().
+**/
+#define SPHandleLargeDelays
+
+
+/**
+ * Debug output
+ *
+ * If defined, outputs a trace of every call using Serial.print.
+ * The performance cost is of course massive, you probably
+ * only want to enable this while debugging the library.
+**/
+//#define SDSerialDebug
+
 #endif