Remove SPI, add UART comm

Core/Inc/stm32f4xx_it.h

@@ -56,9 +56,10 @@ void DebugMon_Handler(void);
 void PendSV_Handler(void);
 void SysTick_Handler(void);
 void TIM2_IRQHandler(void);
+void USART1_IRQHandler(void);
 void DMA2_Stream0_IRQHandler(void);
 void DMA2_Stream2_IRQHandler(void);
-void DMA2_Stream3_IRQHandler(void);
+void DMA2_Stream7_IRQHandler(void);
 /* USER CODE BEGIN EFP */
 
 /* USER CODE END EFP */