Interfacing Osram SCDQ5541 dot-matrix display with an Arduino

scdq5541.pde

class SCDQ5541 {
  private:
    int m_clock, m_data, m_load;
  
    void bitbang(unsigned char code)
    {
      digitalWrite(m_load, LOW);
      for (int i = 0; i < 8; i++) {
           digitalWrite(m_clock, LOW);
           digitalWrite(m_data, code & 0x01);
           digitalWrite(m_clock, HIGH);
           code >>= 1;
      }
      digitalWrite(m_load, HIGH);
    }
  public:
    SCDQ5541(int clock, int data, int load)
      : m_clock(clock)
      , m_data(data)
      , m_load(load) {}
    void begin();
    void clear();
    void sendDigitData(int digit, char *digitData);
    void setBrightness(int percent);
    void setPowerdownMode(boolean on);
    void setLampTest(boolean on);
};

void SCDQ5541::clear()
{
  bitbang(0xc0);
}

void SCDQ5541::setBrightness(int percent)
{
  bitbang(0xf0 + map(percent, 0, 100, 6, 0));
}

void SCDQ5541::setPowerdownMode(boolean on)
{
  if (on)
    bitbang(0xff);
  else
    setBrightness(100);
}

void SCDQ5541::setLampTest(boolean on)
{
  if (on)
    bitbang(0xf8);
  else
    clear();
}

void SCDQ5541::begin()
{
  pinMode(m_clock, OUTPUT);
  pinMode(m_data, OUTPUT);
  pinMode(m_load, OUTPUT);
  clear();
}

void SCDQ5541::sendDigitData(int digit, char *rowData)
{
  if (digit < 0 || digit > 3)
    return;
  bitbang(0xa0 + digit);
  for (int row = 0; row < 5; row++) {
    bitbang(rowData[row] | row << 5);
  }
}

SCDQ5541 ledMatrix(5, 6, 7);

void setup() {
  ledMatrix.begin();
  ledMatrix.sendDigitData(0, (char[]){ 0b11111, 0b10001, 0b10001, 0b10001, 0b11111 });
  ledMatrix.sendDigitData(1, (char[]){ 0b10001, 0b01010, 0b00100, 0b01010, 0b10001 });
  ledMatrix.sendDigitData(2, (char[]){ 0b00100, 0b01010, 0b10001, 0b01010, 0b00100 });
  ledMatrix.sendDigitData(3, (char[]){ 0b00100, 0b01010, 0b01010, 0b10001, 0b11111 });
}

void loop() {
  static int b = 0;
  ledMatrix.setBrightness(b);
  b = (b + 5) % 100;
  delay(50);
}