[lcd] add support for operating on virtual framebuffers

Current implementation contains full support for:
- transparent switching between direct and framebuffer rendering modes
- writing characters to framebuffers
- loading frame from memory to physical display

As well as partial support for instruction writes including:
- resetting the display (clears memory, sets cursor at 0:0, switches to increment mode)
- switching between increment/decrement modes
- setting cursor position

Core/Src/main.c

@@ -30,7 +30,6 @@
 #include "CS43L22.h"
 #include "SST25VF016B.h"
 #include "LIS302DL.h"
-#include "DHT11.h"
 #include "MP45DT02.h"
 #include "LSM9DS1.h"
 
@@ -65,6 +64,8 @@ SPI_HandleTypeDef hspi1;
 
 TIM_HandleTypeDef htim2;
 
+extern size_t display_current_frame;
+
 /* USER CODE BEGIN PV */
 
 void ((*executors[])(void)) = {
@@ -305,10 +306,30 @@ int main(void)
   GPIOD->ODR = 0xF000;
   button_init_and_test();
 
+  // perform all tests
+  display_to_framebuffer();
+
+  for (display_current_frame = 0; display_current_frame < 11; display_current_frame++)
+  {
+	  executors[display_current_frame]();
+  }
+
+  display_to_direct();
+  display_current_frame = 0;
+
+  while (1) {
+	  display_load(display_current_frame);
+	  display_current_frame++;
+	  display_current_frame %= 11;
+	  HAL_Delay(1000);
+  }
+
   /* USER CODE END 2 */
 
   /* Infinite loop */
   /* USER CODE BEGIN WHILE */
+
+  /*
   while (1)
   {
 	if (delay_between_runs[current_executor_id] == -1 && buttons_interrupt_enabled)
@@ -334,10 +355,11 @@ int main(void)
 	} else {
 		HAL_Delay(delay_between_runs[current_executor_id]);
 	}
+	*/
     /* USER CODE END WHILE */
 
     /* USER CODE BEGIN 3 */
-  }
+  //}
   /* USER CODE END 3 */
 }