diff --git a/lib/src/oled/oled.cpp b/lib/src/oled/oled.cpp
index 547f8a3..e2077b0 100644
--- a/lib/src/oled/oled.cpp
+++ b/lib/src/oled/oled.cpp
@@ -45,6 +45,9 @@ void OLED_Turn(OLED_T *dev, bool e) {
 
 void OLED_Refresh(OLED_T *dev) {
     uint8_t i, cmd[3] = {0xb0, 0x00, 0x10};
+#if REFRESH_CALL_ENABLE
+    dev->call();
+#else
     if (dev->state == IDLE) {
         dev->state = REFRESH;
         for (i = 0; i < (dev->height >> 3); i++) {
@@ -52,10 +55,9 @@ void OLED_Refresh(OLED_T *dev) {
             dev->cmd(cmd, 3);
             dev->data(dev->buf + (i * dev->width), dev->width);
         }
-#if REFRESH_CALL_ENABLE
-        dev->call();
-#endif
+        dev->state=IDLE;
     }
+#endif
 }
 
 void OLED_DisplayTurn(OLED_T *dev, bool e) {
@@ -180,9 +182,22 @@ void OLED_ShowString(OLED_T *dev, uint8_t x, uint8_t y, uint8_t *chr, uint8_t si
     }
 }
 
+void OLED_Fill(OLED_T *dev, uint8_t data) {
+    uint8_t x, y;
+    for (y = 0; y < (dev->height >> 3); y++) {
+        for (x = 0; x < dev->width; x++) {
+            BUFPOINT(x, y) = data;
+        }
+    }
+}
+
+void OLED_CLS(OLED_T *dev) {
+    OLED_Fill(dev, 0x00);
+}
+
 void OLED_SPos(OLED_T *dev, uint8_t x, uint8_t y) {
     uint8_t cmd[3];
-    cmd[0] = (uint8_t) 0xb0 + y;
+    cmd[0] = 0xb0 + y;
     cmd[1] = ((x & 0xf0) >> 4) | 0x10;
     cmd[2] = (x & 0x0f) | 0x01;
     if (dev->state == IDLE) {