diff --git a/README.md b/README.md
index 8aeceb7..e6b65df 100644
--- a/README.md
+++ b/README.md
@@ -26,10 +26,9 @@ Virtual FPGA需要使用Verilator生成的一些接口。
 当你在虚拟FPGA上改变输入（比如拨动一个开关）的时候，
 虚拟FPGA会自动调用`update_input()`，让你编写的模块能够收到这个改变。
 模块得到新的输出之后，虚拟FPGA会调用`update_output()`，把模块的输出同步到GUI上。
-
 ##### 体验虚拟FPGA
 
-要改变某个按键或开关的状态，可以使用键盘快捷键，也可以点击鼠标。
+要改变某个按键或开关的状态，可以使用键盘快捷键，将来也可以点击鼠标。
 
 #### 参与贡献
 
diff --git a/build/emu_board b/build/emu_board
deleted file mode 100755
index 834930f..0000000
Binary files a/build/emu_board and /dev/null differ
diff --git a/include/configs.h b/include/configs.h
index 019f806..db9dc7f 100644
--- a/include/configs.h
+++ b/include/configs.h
@@ -5,7 +5,7 @@
 // You can replace pictures used in GUI
 
 // 640*480 png
-#define BG_PATH "vbg_1.png"
+#define BG_PATH "vbg_2.png"
 
 // png
 #define VBTN_ON_PATH "vbtn_on.png"
@@ -17,7 +17,7 @@
 
 // png
 #define SEG_BKGND_ENA
-//#define SEG_BKGND_CUSTOM
+#define SEG_BKGND_CUSTOM
 #define VSEGLED_BG_PATH "vsegled_bg.png"
 
 #endif
\ No newline at end of file
diff --git a/include/constrs.h b/include/constrs.h
index 9fe7738..0baff2c 100644
--- a/include/constrs.h
+++ b/include/constrs.h
@@ -28,9 +28,10 @@ void init_output();
 
 #define RGB_LEDS "r16", "g16", "b16", "r17", "g17", "b17"
 
-#define SEG7_LEDS "an0", "an1", "an2", "an3", \
-                  "an4", "an5", "an6", "an7", \
-                  "sega", "segb", "segc", "segd", \
+#define SEG7_ENBS "an0", "an1", "an2", "an3", \
+                  "an4", "an5", "an6", "an7"
+
+#define SEG7_SEGS "sega", "segb", "segc", "segd", \
                   "sege", "segf", "segg", "decp"
 
 //#define UART_OUTPUT
diff --git a/include/render.h b/include/render.h
index 207a5fd..6fe263b 100644
--- a/include/render.h
+++ b/include/render.h
@@ -31,14 +31,13 @@
 #define SEG_VER_HEIGHT 40
 #define SEG_HOR_WIDTH  40
 #define SEG_HOR_HEIGHT 2
-#define SEG_DOT_WIDTH  2
-#define SEG_DOT_HEIGHT 2
+#define SEG_DOT_WIDTH  SEG_VER_WIDTH
+#define SEG_DOT_HEIGHT SEG_HOR_HEIGHT
 
-#define SEG_WIDTH_MARGIN  2
-#define SEG_HEIGHT_MARGIN 2
+#define SEG_SEP        2
 
-#define SEG_TOT_WIDTH  (SEG_WIDTH_MARGIN * 17 + SEG_VER_WIDTH * 24 + SEG_HOR_WIDTH * 8)
-#define SEG_TOT_HEIGHT (SEG_HEIGHT_MARGIN * 2 + SEG_VER_HEIGHT * 2 + SEG_HOR_HEIGHT)
+#define SEG_TOT_WIDTH  (SEG_SEP * 17 + SEG_VER_WIDTH * 24 + SEG_HOR_WIDTH * 8)
+#define SEG_TOT_HEIGHT (SEG_SEP * 2 + SEG_VER_HEIGHT * 2 + SEG_HOR_HEIGHT * 3)
 
 void load_background(SDL_Renderer *renderer);
 
diff --git a/pic/vbg_2.png b/pic/vbg_2.png
new file mode 100644
index 0000000..cacbdf3
Binary files /dev/null and b/pic/vbg_2.png differ
diff --git a/pic/vbtn_off.png b/pic/vbtn_off.png
index be74056..0dba63b 100644
Binary files a/pic/vbtn_off.png and b/pic/vbtn_off.png differ
diff --git a/pic/vbtn_on.png b/pic/vbtn_on.png
index 36d83ec..065e3cd 100644
Binary files a/pic/vbtn_on.png and b/pic/vbtn_on.png differ
diff --git a/src/constrs.cpp b/src/constrs.cpp
index ce724a1..bab90ef 100644
--- a/src/constrs.cpp
+++ b/src/constrs.cpp
@@ -14,7 +14,7 @@ std::string input_pins[] = {
 const int input_size = sizeof(input_pins) / sizeof(std::string);
 
 std::string output_pins[] = {
-  NAIVE_LEDS, RGB_LEDS, SEG7_LEDS
+  NAIVE_LEDS, RGB_LEDS, SEG7_ENBS, SEG7_SEGS
 };
 
 const int output_size = sizeof(output_pins) / sizeof(std::string);
diff --git a/src/main.cpp b/src/main.cpp
index 1cffcb0..909c3f8 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -11,6 +11,7 @@ TOP_NAME *dut_ptr;
 std::string nboard_home;
 
 int main() {
+  printf("nboard v0.1\n");
   // init verilog module
   dut_ptr = new TOP_NAME;
   
@@ -43,7 +44,6 @@ int main() {
       update_input(dut_ptr);
       update_gui_input(render);
       dut_ptr->eval();
-      printf("out : %d %d %d %d\n", (dut_ptr->out >> 3) & 1, (dut_ptr->out >> 2) & 1, (dut_ptr->out >> 1) & 1, (dut_ptr->out >> 0) & 1);
       update_output(dut_ptr);
       update_gui_output(render);
     }
diff --git a/src/render.cpp b/src/render.cpp
index 28fc2a7..bea7f51 100644
--- a/src/render.cpp
+++ b/src/render.cpp
@@ -27,6 +27,26 @@ static SDL_Texture *tled_off, *tled_r, *tled_g, *tled_b,
 static SDL_Texture *tfpga_background;
 static SDL_Texture *tseg7_background;
 
+static SDL_Rect segs_rect[8] = {
+  {SEG_X + SEG_SEP + SEG_VER_WIDTH, SEG_Y + SEG_SEP, SEG_HOR_WIDTH, SEG_HOR_HEIGHT},
+  {SEG_X + SEG_SEP + SEG_VER_WIDTH + SEG_HOR_WIDTH, SEG_Y + SEG_SEP + SEG_HOR_HEIGHT, SEG_VER_WIDTH, SEG_VER_HEIGHT},
+  {SEG_X + SEG_SEP + SEG_VER_WIDTH + SEG_HOR_WIDTH, SEG_Y + SEG_SEP + 2 * SEG_HOR_HEIGHT + SEG_VER_HEIGHT, SEG_VER_WIDTH, SEG_VER_HEIGHT},
+  {SEG_X + SEG_SEP + SEG_VER_WIDTH, SEG_Y + SEG_SEP + 2 * SEG_HOR_HEIGHT + 2 * SEG_VER_HEIGHT, SEG_HOR_WIDTH, SEG_HOR_HEIGHT},
+  {SEG_X + SEG_SEP, SEG_Y + SEG_SEP + 2 * SEG_HOR_HEIGHT + SEG_VER_HEIGHT, SEG_VER_WIDTH, SEG_VER_HEIGHT},
+  {SEG_X + SEG_SEP, SEG_Y + SEG_SEP + SEG_HOR_HEIGHT, SEG_VER_WIDTH, SEG_VER_HEIGHT},
+  {SEG_X + SEG_SEP + SEG_VER_WIDTH, SEG_Y + SEG_SEP + SEG_HOR_HEIGHT + SEG_VER_HEIGHT, SEG_HOR_WIDTH, SEG_HOR_HEIGHT},
+  {SEG_X + 2 * SEG_SEP + 2 * SEG_VER_WIDTH + SEG_HOR_WIDTH, SEG_Y + SEG_SEP + 2 * SEG_HOR_HEIGHT + 2 * SEG_VER_HEIGHT, SEG_DOT_WIDTH, SEG_DOT_HEIGHT}
+};
+
+SDL_Rect operator+(const SDL_Rect &A, const SDL_Rect &B) {
+  SDL_Rect ret;
+  ret.x = A.x + B.x;
+  ret.y = A.y + B.y;
+  ret.w = A.w + B.w;
+  ret.h = A.h + B.h;
+  return ret;
+}
+
 extern std::string nboard_home;
 
 void load_background(SDL_Renderer *renderer) {
@@ -131,7 +151,7 @@ std::string input_switches[] = {
 static const int switches_cnt = sizeof(input_switches) / sizeof(std::string);
 
 static void update_gui_switch(SDL_Renderer *renderer, int index, bool val) {
-  index = 15 - index;
+  index = switches_cnt - 1 - index;
   SDL_Rect rect = {SWITCH_X + (SWITCH_WIDTH + SWITCH_SEP) * index, SWITCH_Y, SWITCH_WIDTH, SWITCH_HEIGHT};
   SDL_RenderCopy(renderer, val ? tswitch_on : tswitch_off, NULL, &rect);
 }
@@ -192,13 +212,19 @@ std::string output_rgb_leds[] = {
   RGB_LEDS
 };
 
-std::string output_seg7_leds[] = {
-  SEG7_LEDS
+std::string output_seg7_enbs[] = {
+  SEG7_ENBS
 };
+const int seg7_enbs_cnt = sizeof(output_seg7_enbs) / sizeof(std::string);
+
+std::string output_seg7_segs[] = {
+  SEG7_SEGS
+};
+const int seg7_segs_cnt = sizeof(output_seg7_segs) / sizeof(std::string);
 
 static void update_gui_naive_led(SDL_Renderer *renderer, int index, bool val) {
   //std::cout << "update " << index << std::endl;
-  index = 15 - index;
+  index = naive_leds_cnt - 1 - index;
   SDL_Rect rect = {LED_X + (LED_WIDTH + LED_SEP) * index, LED_Y, LED_WIDTH, LED_HEIGHT};
   SDL_RenderCopy(renderer, val ? tled_g : tled_off, NULL, &rect);
 }
@@ -237,6 +263,22 @@ static void update_gui_rgb_led(SDL_Renderer *renderer, int index, int color) {
   }
 }
 
+static void update_gui_7segs(SDL_Renderer *renderer, int index, bool enable) {
+  SDL_Rect move = {index * (SEG_HOR_WIDTH + SEG_DOT_WIDTH + SEG_SEP * 4), 0, 0, 0};
+  SDL_Rect dst_rect[8];
+  for (int i = 0; i < 8; ++i) {
+    dst_rect[i] = move + segs_rect[i];
+  }
+  SDL_RenderCopy(renderer, (enable && !output_map["sega"]) ? tsegled_hor_on : tsegled_hor_off, NULL, &dst_rect[0]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segb"]) ? tsegled_ver_on : tsegled_ver_off, NULL, &dst_rect[1]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segc"]) ? tsegled_ver_on : tsegled_ver_off, NULL, &dst_rect[2]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segd"]) ? tsegled_hor_on : tsegled_hor_off, NULL, &dst_rect[3]);
+  SDL_RenderCopy(renderer, (enable && !output_map["sege"]) ? tsegled_ver_on : tsegled_ver_off, NULL, &dst_rect[4]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segf"]) ? tsegled_ver_on : tsegled_ver_off, NULL, &dst_rect[5]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segg"]) ? tsegled_hor_on : tsegled_hor_off, NULL, &dst_rect[6]);
+  SDL_RenderCopy(renderer, (enable && !output_map["segb"]) ? tsegled_dot_on : tsegled_dot_off, NULL, &dst_rect[7]);
+}
+
 // After SDL receives the changes of inputs, call update_gui_input() 
 
 // After updating the outputs of module, call update_gui_output()
@@ -268,6 +310,14 @@ void update_gui_output(SDL_Renderer *renderer) {
   }
   
   // check seg7s
+  for (int i = 0; i < seg7_enbs_cnt; ++i) {
+    std::string &str = output_seg7_enbs[i];
+    if (output_map.count(str)) {
+      if (output_map[str] || (prev_output_map[str] != output_map[str])) {
+        update_gui_7segs(renderer, i, output_map[str]);
+      }
+    }
+  }
 
   SDL_RenderPresent(renderer);
   return;
@@ -288,6 +338,10 @@ void init_gui(SDL_Renderer *renderer) {
   for (int i = 0; i < naive_leds_cnt; ++i) {
     update_gui_naive_led(renderer, i, 0);
   }
+
+  for (int i = 0; i < seg7_enbs_cnt; ++i) {
+    update_gui_7segs(renderer, i, 0);
+  }
  
   SDL_RenderPresent(renderer);
 }
\ No newline at end of file