ISSUE #21: Problems on clearDisplay and setupDisplay

CHANGES.txt

@@ -1,3 +1,5 @@
+- ISSUE #21: Problems on clearDisplay and setupDisplay;
+
 Version 2.1.0
 
 - ISSUE #20: Support for negative decimal numbers;

TM1640.cpp

@@ -36,3 +36,13 @@ void TM1640::sendChar(byte pos, byte data, boolean dot)
 {
   sendData(pos, data | (dot ? 0b10000000 : 0));
 }
+
+void TM1640::clearDisplay()
+{
+  digitalWrite(strobePin, LOW);
+  send(0xC0);
+  for (int i = 0; i < 16; i++) {
+    send(0x00);
+  }
+  digitalWrite(strobePin, HIGH);
+}

TM1640.h

@@ -33,6 +33,8 @@ class TM1640 : public TM16XX
   public:
 	/** Instantiate a tm1640 module specifying the display state, the starting intensity (0-7) data and clock pins. */
   	TM1640(byte dataPin, byte clockPin, boolean activateDisplay = true, byte intensity = 7);
+    /** Clear the display */
+	virtual void clearDisplay();
 
   protected:
     virtual void sendChar(byte pos, byte data, boolean dot);

TM16XX.cpp

@@ -54,6 +54,12 @@ TM16XX::TM16XX(byte dataPin, byte clockPin, byte strobePin, byte displays, boole
 void TM16XX::setupDisplay(boolean active, byte intensity)
 {
   sendCommand(0x80 | (active ? 8 : 0) | min(7, intensity));
+
+  // necessary for the TM1640
+  digitalWrite(strobePin, LOW);
+  digitalWrite(clockPin, LOW);
+  digitalWrite(clockPin, HIGH);
+  digitalWrite(strobePin, HIGH);
 }
 
 void TM16XX::setDisplayDigit(byte digit, byte pos, boolean dot, const byte numberFont[])