[main] add simple navigation between test reports

Core/Inc/lcd.h

@@ -29,5 +29,6 @@ void display_write_data_byte(uint8_t code);
 void display_write_data_seq(char *codes);
 void display_to_framebuffer(void);
 void display_to_direct(void);
+void display_load(uint32_t frame_no);
 
 #endif

Core/Src/main.c

@@ -315,13 +315,53 @@ int main(void)
   }
 
   display_to_direct();
+
   display_current_frame = 0;
 
+  if (buttons_interrupt_enabled)
+	  buttons_switch_to_input();
+
   while (1) {
+	  // wait until all buttons are released
+	  while (
+			  (GPIOA->IDR & GPIO_PIN_0) ||
+			  !(GPIOC->IDR & GPIO_PIN_11) ||
+			  !(GPIOC->IDR & GPIO_PIN_8) ||
+			  !(GPIOC->IDR & GPIO_PIN_9) ||
+			  !(GPIOC->IDR & GPIO_PIN_6) ||
+			  !(GPIOA->IDR & GPIO_PIN_15)
+	  ) { asm("nop"); }
+
 	  display_load(display_current_frame);
-	  display_current_frame++;
-	  display_current_frame %= 11;
-	  HAL_Delay(1000);
+
+	  while (1) {
+		  // go to next report
+		  if (
+				  (GPIOA->IDR & GPIO_PIN_0) ||
+				  !(GPIOC->IDR & GPIO_PIN_11) ||
+				  !(GPIOC->IDR & GPIO_PIN_8)
+		  ) {
+			  display_current_frame += 1;
+			  break;
+		  }
+
+		  // go to previous report
+		  else if (
+				  !(GPIOC->IDR & GPIO_PIN_9) ||
+		  	  	  !(GPIOC->IDR & GPIO_PIN_6)
+	  	  ) {
+			  display_current_frame -= 1;
+			  break;
+		  }
+
+		  // execute this test live
+		  else if (
+				  !(GPIOA->IDR & GPIO_PIN_15)
+		  ) {
+			  // not implemented
+			  continue;
+		  }
+	  }
   }
 
   /* USER CODE END 2 */