diff --git a/Downstream/Drivers/CMSIS/Include/core_cm4.h b/Downstream/Drivers/CMSIS/Include/core_cm4.h
index 827dc38..d62032c 100644
--- a/Downstream/Drivers/CMSIS/Include/core_cm4.h
+++ b/Downstream/Drivers/CMSIS/Include/core_cm4.h
@@ -1706,7 +1706,7 @@ __STATIC_INLINE uint32_t SysTick_Config(uint32_t ticks)
   if ((ticks - 1) > SysTick_LOAD_RELOAD_Msk)  return (1);      /* Reload value impossible */
 
   SysTick->LOAD  = ticks - 1;                                  /* set reload register */
-  NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1);  /* set Priority for Systick Interrupt */
+  //NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1);  /* set Priority for Systick Interrupt */
   SysTick->VAL   = 0;                                          /* Load the SysTick Counter Value */
   SysTick->CTRL  = SysTick_CTRL_CLKSOURCE_Msk |
                    SysTick_CTRL_TICKINT_Msk   |
diff --git a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal.c b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal.c
index 35d9379..8e1c314 100644
--- a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal.c
+++ b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal.c
@@ -266,7 +266,7 @@ __weak HAL_StatusTypeDef HAL_InitTick(uint32_t TickPriority)
   HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
 
   /*Configure the SysTick IRQ priority */
-  HAL_NVIC_SetPriority(SysTick_IRQn, TickPriority ,0);
+  //HAL_NVIC_SetPriority(SysTick_IRQn, TickPriority ,0);
 
   /* Return function status */
   return HAL_OK;
diff --git a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_rcc.c b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_rcc.c
index 46b4d6d..803979c 100644
--- a/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_rcc.c
+++ b/Downstream/Drivers/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_rcc.c
@@ -280,10 +280,10 @@ __weak HAL_StatusTypeDef HAL_RCC_OscConfig(RCC_OscInitTypeDef  *RCC_OscInitStruc
     if((__HAL_RCC_GET_SYSCLK_SOURCE() == RCC_CFGR_SWS_HSE)                                                                     ||\
       ((__HAL_RCC_GET_SYSCLK_SOURCE() == RCC_CFGR_SWS_PLL) && ((RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC) == RCC_PLLCFGR_PLLSRC_HSE)))
     {
-      if((__HAL_RCC_GET_FLAG(RCC_FLAG_HSERDY) != RESET) && (RCC_OscInitStruct->HSEState == RCC_HSE_OFF))
-      {
+//      if((__HAL_RCC_GET_FLAG(RCC_FLAG_HSERDY) != RESET) && (RCC_OscInitStruct->HSEState == RCC_HSE_OFF))
+//      {
         return HAL_ERROR;
-      }
+//      }
     }
     else
     {
diff --git a/Downstream/Inc/board_config.h b/Downstream/Inc/board_config.h
new file mode 100644
index 0000000..5b2c897
--- /dev/null
+++ b/Downstream/Inc/board_config.h
@@ -0,0 +1,52 @@
+/*
+ * board_config.h
+ *
+ *  Created on: 25/03/2015
+ *      Author: Robert Fisk
+ */
+
+#ifndef INC_BOARD_CONFIG_H_
+#define INC_BOARD_CONFIG_H_
+
+
+#define BSRR_SHIFT_HIGH			0
+#define BSRR_SHIFT_LOW			16
+
+#define PA_JTMS					GPIO_PIN_13
+#define PA_JTCK					GPIO_PIN_14
+#define PA_JTDI					GPIO_PIN_15
+#define PB_JTDO					GPIO_PIN_3
+#define PB_NJTRST				GPIO_PIN_4
+
+#define USB_FS_VBUS_PIN			GPIO_PIN_9
+#define USB_FS_VBUS_PORT		GPIOA
+#define USB_FS_VBUSON_PIN		GPIO_PIN_10
+#define USB_FS_VBUSON_PORT		GPIOA
+#define USB_FS_FAULT_PIN		GPIO_PIN_6
+#define USB_FS_FAULT_PORT		GPIOB
+
+#define USB_HS_VBUS_PIN			GPIO_PIN_13
+#define USB_HS_VBUS_PORT		GPIOB
+#define USB_HS_VBUSON_PIN		GPIO_PIN_8
+#define USB_HS_VBUSON_PORT		GPIOA
+
+#define STAT_LED_PIN			GPIO_PIN_13
+#define STAT_LED_PORT			GPIOC
+#define STAT_LED_ON				(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_LOW))	//Stat LED is active-low
+#define STAT_LED_OFF			(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_HIGH))
+
+//#define SPI_DMA_ACTIVE_PIN		GPIO_PIN_5		/////////Temporary indicator of SPI & DMA activity
+//#define SPI_DMA_ACTIVE_PORT		GPIOB
+//#define SPI_DMA_ACTIVE_ON		SPI_DMA_ACTIVE_PORT->BSRR = (SPI_DMA_ACTIVE_PIN << BSRR_SHIFT_LOW)
+//#define SPI_DMA_ACTIVE_OFF		SPI_DMA_ACTIVE_PORT->BSRR = (SPI_DMA_ACTIVE_PIN << BSRR_SHIFT_HIGH)
+
+#define SPI1_NSS_PIN			GPIO_PIN_4
+#define SPI1_NSS_PORT			GPIOA
+
+#define UPSTREAM_TX_REQUEST_PIN			GPIO_PIN_3
+#define UPSTREAM_TX_REQUEST_PORT		GPIOA
+#define UPSTREAM_TX_REQUEST_ASSERT		(UPSTREAM_TX_REQUEST_PORT->BSRR = (UPSTREAM_TX_REQUEST_PIN << BSRR_SHIFT_LOW))
+#define UPSTREAM_TX_REQUEST_DEASSERT	(UPSTREAM_TX_REQUEST_PORT->BSRR = (UPSTREAM_TX_REQUEST_PIN << BSRR_SHIFT_HIGH))
+
+
+#endif /* INC_BOARD_CONFIG_H_ */
diff --git a/Downstream/Inc/interrupts.h b/Downstream/Inc/interrupts.h
index 862d2df..3d94804 100644
--- a/Downstream/Inc/interrupts.h
+++ b/Downstream/Inc/interrupts.h
@@ -42,7 +42,13 @@
 /* Includes ------------------------------------------------------------------*/
 /* Exported types ------------------------------------------------------------*/
 /* Exported constants --------------------------------------------------------*/
-/* Exported macro ------------------------------------------------------------*/
+
+#define INT_PRIORITY_SYSTICK	2
+#define INT_PRIORITY_SPI_DMA	10			//SPI interacts heavily with USB_OTG,
+#define INT_PRIORITY_OTG_FS		10			//so set them at the same priority.
+
+
+ /* Exported macro ------------------------------------------------------------*/
 /* Exported functions ------------------------------------------------------- */
 
 void SysTick_Handler(void);
diff --git a/Downstream/Src/hal_msp.c b/Downstream/Src/hal_msp.c
index cb71dbf..dbead96 100644
--- a/Downstream/Src/hal_msp.c
+++ b/Downstream/Src/hal_msp.c
@@ -33,45 +33,27 @@
   */
 /* Includes ------------------------------------------------------------------*/
 #include "stm32f4xx_hal.h"
+#include "interrupts.h"
 
-extern DMA_HandleTypeDef hdma_spi1_rx;
 
+extern DMA_HandleTypeDef hdma_spi1_rx;
 extern DMA_HandleTypeDef hdma_spi1_tx;
 
-/* USER CODE BEGIN 0 */
 
-/* USER CODE END 0 */
 
-/**
-  * Initializes the Global MSP.
-  */
 void HAL_MspInit(void)
 {
-  /* USER CODE BEGIN MspInit 0 */
-
-  /* USER CODE END MspInit 0 */
 
-  HAL_NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);
-
-  /* System interrupt init*/
-/* SysTick_IRQn interrupt configuration */
-  HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
-
-  /* USER CODE BEGIN MspInit 1 */
-
-  /* USER CODE END MspInit 1 */
+  HAL_NVIC_SetPriority(SysTick_IRQn, INT_PRIORITY_SYSTICK, 0);
 }
 
+
 void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
 {
 
   GPIO_InitTypeDef GPIO_InitStruct;
   if(hspi->Instance==SPI1)
   {
-  /* USER CODE BEGIN SPI1_MspInit 0 */
-
-  /* USER CODE END SPI1_MspInit 0 */
-    /* Peripheral clock enable */
     __SPI1_CLK_ENABLE();
   
     /**SPI1 GPIO Configuration    
@@ -82,12 +64,11 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
     GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7;
     GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
     GPIO_InitStruct.Pull = GPIO_NOPULL;
-    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
+    GPIO_InitStruct.Speed = GPIO_SPEED_MEDIUM;
     GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
     HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
     /* Peripheral DMA init*/
-  
     hdma_spi1_rx.Instance = DMA2_Stream2;
     hdma_spi1_rx.Init.Channel = DMA_CHANNEL_3;
     hdma_spi1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
@@ -122,9 +103,6 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
 
     __HAL_LINKDMA(hspi,hdmatx,hdma_spi1_tx);
 
-  /* USER CODE BEGIN SPI1_MspInit 1 */
-
-  /* USER CODE END SPI1_MspInit 1 */
   }
 
 }
@@ -134,10 +112,6 @@ void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
 
   if(hspi->Instance==SPI1)
   {
-  /* USER CODE BEGIN SPI1_MspDeInit 0 */
-
-  /* USER CODE END SPI1_MspDeInit 0 */
-    /* Peripheral clock disable */
     __SPI1_CLK_DISABLE();
   
     /**SPI1 GPIO Configuration    
@@ -151,19 +125,9 @@ void HAL_SPI_MspDeInit(SPI_HandleTypeDef* hspi)
     HAL_DMA_DeInit(hspi->hdmarx);
     HAL_DMA_DeInit(hspi->hdmatx);
   }
-  /* USER CODE BEGIN SPI1_MspDeInit 1 */
-
-  /* USER CODE END SPI1_MspDeInit 1 */
 
 }
 
-/* USER CODE BEGIN 1 */
-
-/* USER CODE END 1 */
-
-/**
-  * @}
-  */
 
 /**
   * @}
diff --git a/Downstream/Src/interrupts.c b/Downstream/Src/interrupts.c
index 36194b0..914b71c 100644
--- a/Downstream/Src/interrupts.c
+++ b/Downstream/Src/interrupts.c
@@ -35,9 +35,6 @@
 #include "stm32f4xx.h"
 #include "interrupts.h"
 
-/* USER CODE BEGIN 0 */
-
-/* USER CODE END 0 */
 
 /* External variables --------------------------------------------------------*/
 extern HCD_HandleTypeDef hhcd_USB_OTG_FS;
@@ -53,14 +50,7 @@ extern DMA_HandleTypeDef hdma_spi1_tx;
 */
 void SysTick_Handler(void)
 {
-  /* USER CODE BEGIN SysTick_IRQn 0 */
-
-  /* USER CODE END SysTick_IRQn 0 */
   HAL_IncTick();
-  HAL_SYSTICK_IRQHandler();
-  /* USER CODE BEGIN SysTick_IRQn 1 */
-
-  /* USER CODE END SysTick_IRQn 1 */
 }
 
 /******************************************************************************/
@@ -75,13 +65,7 @@ void SysTick_Handler(void)
 */
 void DMA2_Stream2_IRQHandler(void)
 {
-  /* USER CODE BEGIN DMA2_Stream2_IRQn 0 */
-
-  /* USER CODE END DMA2_Stream2_IRQn 0 */
   HAL_DMA_IRQHandler(&hdma_spi1_rx);
-  /* USER CODE BEGIN DMA2_Stream2_IRQn 1 */
-
-  /* USER CODE END DMA2_Stream2_IRQn 1 */
 }
 
 /**
@@ -89,13 +73,7 @@ void DMA2_Stream2_IRQHandler(void)
 */
 void DMA2_Stream3_IRQHandler(void)
 {
-  /* USER CODE BEGIN DMA2_Stream3_IRQn 0 */
-
-  /* USER CODE END DMA2_Stream3_IRQn 0 */
   HAL_DMA_IRQHandler(&hdma_spi1_tx);
-  /* USER CODE BEGIN DMA2_Stream3_IRQn 1 */
-
-  /* USER CODE END DMA2_Stream3_IRQn 1 */
 }
 
 /**
@@ -103,16 +81,8 @@ void DMA2_Stream3_IRQHandler(void)
 */
 void OTG_FS_IRQHandler(void)
 {
-  /* USER CODE BEGIN OTG_FS_IRQn 0 */
-
-  /* USER CODE END OTG_FS_IRQn 0 */
   HAL_HCD_IRQHandler(&hhcd_USB_OTG_FS);
-  /* USER CODE BEGIN OTG_FS_IRQn 1 */
-
-  /* USER CODE END OTG_FS_IRQn 1 */
 }
 
-/* USER CODE BEGIN 1 */
 
-/* USER CODE END 1 */
 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
diff --git a/Downstream/Src/main.c b/Downstream/Src/main.c
index 618af68..e37e5a9 100644
--- a/Downstream/Src/main.c
+++ b/Downstream/Src/main.c
@@ -33,20 +33,15 @@
 /* Includes ------------------------------------------------------------------*/
 #include "stm32f4xx_hal.h"
 #include "usb_host.h"
+#include "board_config.h"
 
-/* USER CODE BEGIN Includes */
-
-/* USER CODE END Includes */
 
 /* Private variables ---------------------------------------------------------*/
 SPI_HandleTypeDef hspi1;
 DMA_HandleTypeDef hdma_spi1_rx;
 DMA_HandleTypeDef hdma_spi1_tx;
 
-/* USER CODE BEGIN PV */
-/* Private variables ---------------------------------------------------------*/
 
-/* USER CODE END PV */
 
 /* Private function prototypes -----------------------------------------------*/
 void SystemClock_Config(void);
@@ -55,54 +50,33 @@ static void MX_DMA_Init(void);
 static void MX_SPI1_Init(void);
 void MX_USB_HOST_Process(void);
 
-/* USER CODE BEGIN PFP */
-/* Private function prototypes -----------------------------------------------*/
-
-/* USER CODE END PFP */
-
-/* USER CODE BEGIN 0 */
 
-/* USER CODE END 0 */
 
 int main(void)
 {
-
-  /* USER CODE BEGIN 1 */
-
-  /* USER CODE END 1 */
-
   /* MCU Configuration----------------------------------------------------------*/
 
-  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
-  HAL_Init();
-
-  /* Configure the system clock */
-  SystemClock_Config();
-
-  /* Initialize all configured peripherals */
-  MX_GPIO_Init();
-  MX_DMA_Init();
-  MX_SPI1_Init();
-  MX_USB_HOST_Init();
+	/* Configure the system clock */
+	SystemClock_Config();
 
-  /* USER CODE BEGIN 2 */
+	/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
+	HAL_Init();
 
-  /* USER CODE END 2 */
+	/* Initialize all configured peripherals */
+	MX_GPIO_Init();
+	MX_DMA_Init();
+	MX_SPI1_Init();
+	MX_USB_HOST_Init();
 
-  /* Infinite loop */
-  /* USER CODE BEGIN WHILE */
-  while (1)
-  {
-  /* USER CODE END WHILE */
-    MX_USB_HOST_Process();
 
-  /* USER CODE BEGIN 3 */
-
-  }
-  /* USER CODE END 3 */
+	while (1)
+	{
+		MX_USB_HOST_Process();
 
+	}
 }
 
+
 /** System Clock Configuration
 */
 void SystemClock_Config(void)
@@ -123,7 +97,7 @@ void SystemClock_Config(void)
   RCC_OscInitStruct.PLL.PLLN = 336;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
   RCC_OscInitStruct.PLL.PLLQ = 7;
-  HAL_RCC_OscConfig(&RCC_OscInitStruct);
+  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) while (1);
 
   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1
                               |RCC_CLOCKTYPE_PCLK2;
@@ -131,18 +105,15 @@ void SystemClock_Config(void)
   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
-  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2);
-
-  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
+  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) while (1);
 
   HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
-
 }
 
+
 /* SPI1 init function */
 void MX_SPI1_Init(void)
 {
-
   hspi1.Instance = SPI1;
   hspi1.Init.Mode = SPI_MODE_SLAVE;
   hspi1.Init.Direction = SPI_DIRECTION_2LINES;
@@ -156,9 +127,9 @@ void MX_SPI1_Init(void)
   hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLED;
   hspi1.Init.CRCPolynomial = 10;
   HAL_SPI_Init(&hspi1);
-
 }
 
+
 /** 
   * Enable DMA controller clock
   */
@@ -184,12 +155,58 @@ void MX_DMA_Init(void)
 */
 void MX_GPIO_Init(void)
 {
-
-  /* GPIO Ports Clock Enable */
-  __GPIOH_CLK_ENABLE();
-  __GPIOA_CLK_ENABLE();
-  __GPIOB_CLK_ENABLE();
-
+	GPIO_InitTypeDef GPIO_InitStruct;
+
+	/* GPIO Ports Clock Enable */
+	//__GPIOH_CLK_ENABLE();
+	__HAL_RCC_GPIOA_CLK_ENABLE();
+	__HAL_RCC_GPIOB_CLK_ENABLE();
+	__HAL_RCC_GPIOC_CLK_ENABLE();
+	__HAL_RCC_GPIOD_CLK_ENABLE();
+	__HAL_RCC_GPIOE_CLK_ENABLE();
+	__HAL_RCC_GPIOF_CLK_ENABLE();
+	__HAL_RCC_GPIOG_CLK_ENABLE();
+
+	//Bulk initialise all ports as inputs with pullups active,
+	//excluding JTAG pins which must remain as AF0!
+	GPIO_InitStruct.Pin = (GPIO_PIN_All & ~(PA_JTMS | PA_JTCK | PA_JTDI));
+	GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+	GPIO_InitStruct.Pull = GPIO_PULLUP;
+	GPIO_InitStruct.Speed = GPIO_SPEED_LOW;
+	GPIO_InitStruct.Alternate = 0;
+	HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+	GPIO_InitStruct.Pin = (GPIO_PIN_All & ~(PB_JTDO | PB_NJTRST));
+	HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
+	GPIO_InitStruct.Pin = GPIO_PIN_All;
+	HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
+	HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
+	HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
+	HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);
+	HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);
+
+	//USB VBUS pins are analog input
+	GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
+	GPIO_InitStruct.Pin = USB_FS_VBUS_PIN;
+	HAL_GPIO_Init(USB_FS_VBUS_PORT, &GPIO_InitStruct);
+	GPIO_InitStruct.Pin = USB_HS_VBUS_PIN;
+	HAL_GPIO_Init(USB_HS_VBUS_PORT, &GPIO_InitStruct);
+
+	//Enable USB_FS power
+	USB_FS_VBUSON_PORT->BSRR = (USB_FS_VBUSON_PIN << BSRR_SHIFT_HIGH);
+	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
+	GPIO_InitStruct.Pull = GPIO_NOPULL;
+	GPIO_InitStruct.Pin = USB_FS_VBUSON_PIN;
+	HAL_GPIO_Init(USB_FS_VBUSON_PORT, &GPIO_InitStruct);
+
+	//Disable USB_HS power
+	USB_HS_VBUSON_PORT->BSRR = (USB_HS_VBUSON_PIN << BSRR_SHIFT_LOW);
+	GPIO_InitStruct.Pin = USB_HS_VBUSON_PIN;
+	HAL_GPIO_Init(USB_HS_VBUSON_PORT, &GPIO_InitStruct);
+
+	//STAT_LED is output
+	STAT_LED_OFF;
+	GPIO_InitStruct.Pin = STAT_LED_PIN;
+	HAL_GPIO_Init(STAT_LED_PORT, &GPIO_InitStruct);
 }
 
 /* USER CODE BEGIN 4 */
diff --git a/Upstream/Inc/board_config.h b/Upstream/Inc/board_config.h
index 6b904bb..2c848d1 100644
--- a/Upstream/Inc/board_config.h
+++ b/Upstream/Inc/board_config.h
@@ -23,8 +23,8 @@
 
 #define STAT_LED_PIN			GPIO_PIN_12
 #define STAT_LED_PORT			GPIOC
-#define STAT_LED_ON				STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_LOW)	//Stat LED is active-low
-#define STAT_LED_OFF			STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_HIGH)
+#define STAT_LED_ON				(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_LOW))	//Stat LED is active-low
+#define STAT_LED_OFF			(STAT_LED_PORT->BSRR = (STAT_LED_PIN << BSRR_SHIFT_HIGH))
 
 #define SPI_DMA_ACTIVE_PIN		GPIO_PIN_5		/////////Temporary indicator of SPI & DMA activity
 #define SPI_DMA_ACTIVE_PORT		GPIOB
diff --git a/Upstream/Inc/interrupts.h b/Upstream/Inc/interrupts.h
index a937955..1fd97e9 100755
--- a/Upstream/Inc/interrupts.h
+++ b/Upstream/Inc/interrupts.h
@@ -58,6 +58,10 @@
 
 void OTG_FS_IRQHandler(void);
 void SysTick_Handler(void);
+void DMA2_Stream2_IRQHandler(void);
+void DMA2_Stream3_IRQHandler(void);
+void EXTI3_IRQHandler(void);
+
 
 #ifdef __cplusplus
 }
diff --git a/Upstream/Src/hal_msp.c b/Upstream/Src/hal_msp.c
index ab69075..e3696a4 100755
--- a/Upstream/Src/hal_msp.c
+++ b/Upstream/Src/hal_msp.c
@@ -78,10 +78,19 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
     GPIO_InitStruct.Speed = GPIO_SPEED_MEDIUM;
     GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
     HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+
+    SPI1_NSS_DEASSERT;
     GPIO_InitStruct.Pin = SPI1_NSS_PIN;
     GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
-    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
-    SPI1_NSS_DEASSERT;
+    HAL_GPIO_Init(SPI1_NSS_PORT, &GPIO_InitStruct);
+
+	//Configure downstream request pin and interrupt
+	GPIO_InitStruct.Pin = DOWNSTREAM_TX_OK_PIN;
+	GPIO_InitStruct.Mode = GPIO_MODE_INPUT | GPIO_MODE_IT_FALLING;
+	GPIO_InitStruct.Pull = GPIO_PULLUP;
+	HAL_GPIO_Init(DOWNSTREAM_TX_OK_PORT, &GPIO_InitStruct);
+	HAL_NVIC_SetPriority(EXTI3_IRQn, INT_PRIORITY_SPI_DMA, 0);
+	HAL_NVIC_EnableIRQ(EXTI3_IRQn);
 
 	//Prepare Tx DMA stream
 	hspi->hdmatx = &spiTxDmaHandle;
@@ -116,17 +125,6 @@ void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
 	HAL_DMA_Init(&spiRxDmaHandle);
 	HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, INT_PRIORITY_SPI_DMA, 0);
 	HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
-
-	//Configure downstream request pin and interrupt
-	GPIO_InitStruct.Pin = DOWNSTREAM_TX_OK_PIN;
-	GPIO_InitStruct.Mode = GPIO_MODE_INPUT | GPIO_MODE_IT_FALLING;
-
-	//GPIO_InitStruct.Pull = GPIO_PULLUP;
-	GPIO_InitStruct.Pull = GPIO_PULLDOWN;	////////////////////////////////////////////////!
-
-	HAL_GPIO_Init(DOWNSTREAM_TX_OK_PORT, &GPIO_InitStruct);
-	HAL_NVIC_SetPriority(EXTI3_IRQn, INT_PRIORITY_SPI_DMA, 0);
-	HAL_NVIC_EnableIRQ(EXTI3_IRQn);
   }
 }
 
diff --git a/Upstream/Src/main.c b/Upstream/Src/main.c
index f2227e4..5bc1c31 100755
--- a/Upstream/Src/main.c
+++ b/Upstream/Src/main.c
@@ -54,12 +54,12 @@ int main(void)
 {
   /* MCU Configuration----------------------------------------------------------*/
 
-  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
-  HAL_Init();
-
   /* Configure the system clock */
   SystemClock_Config();
 
+  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
+  HAL_Init();
+
   /* Initialize all configured peripherals */
   GPIO_Init();
   USB_Device_Init();
@@ -67,7 +67,6 @@ int main(void)
   Downstream_InitInterface();
 
 
-
   while (1)
   {
 
@@ -95,7 +94,7 @@ void SystemClock_Config(void)
   RCC_OscInitStruct.PLL.PLLN = 336;
   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
   RCC_OscInitStruct.PLL.PLLQ = 7;
-  if (HAL_RCC_OscConfig(&RCC_OscInitStruct)) while (1);
+  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) while (1);
 
   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1
                               |RCC_CLOCKTYPE_PCLK2;
@@ -104,6 +103,8 @@ void SystemClock_Config(void)
   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2)) while(1);
+
+  HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
 }