completely rewrite the driver.

using one class to descripe two kinds of display.
add two displays used simultaneously example.
use : setTubeType() to select which type of display is going to be used.
add : add comment ,modify configuration files.

examples/display_custom/display_custom.ino

@@ -0,0 +1,81 @@
+/*
+ * display_custom_4.ino
+ * Example for digital tube.
+ *  
+ * Copyright (c) 2018 Seeed Technology Co., Ltd.
+ * Website    : www.seeed.cc
+ * Author     : downey
+ * Create Time: sep. 2018
+ * Change Log :
+ *
+ * The MIT License (MIT)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <Wire.h>
+
+
+/*********************************************************/
+/*****NOTICE : This example only for qual_alphanumeric****/
+/*********************************************************/
+#include "grove_alphanumeric_display.h"
+
+Seeee_Digital_Tube tube;
+
+
+void setup()
+{
+    Wire.begin();
+    
+    // If using two digital tubes, use this configuration.
+    // tube.setTubeType(TYPE_2,TYPE_2_DEFAULT_I2C_ADDR);
+
+    // If using four digital tubes, use this configuration.
+    tube.setTubeType(TYPE_4,TYPE_4_DEFAULT_I2C_ADDR);
+    
+
+    tube.setBrightness(15);
+    tube.setBlinkRate(BLINK_1HZ);
+    
+    
+}
+
+
+void displayCustom()
+{
+    tube.clearBuf();
+    tube.setTubeSingleChar(FIRST_TUBE,'t');
+    tube.setTubeSingleChar(SECOND_TUBE,'T');
+
+    //if using two digital tubes,there's no third&fourth channel.
+
+    tube.setTubeSingleNum(THIRD_TUBE,5);
+    tube.setTubeSingleNum(FOURTH_TUBE,5);
+
+    // The location of point is different between two&four digital tubes.
+    tube.setPoint(true,false);
+
+    tube.display();
+}
+
+void loop()
+{
+    displayCustom();
+    delay(2000);
+}