From 7a4ca0d663390446b2e17d25352d14c0306beeab Mon Sep 17 00:00:00 2001
From: Fredrik Thulin <fredrik@thulin.net>
Date: Thu, 12 May 2016 19:48:47 +0200
Subject: Enable HSE (external clock oscillator).

---
 stm-init.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 stm-init.h |  2 ++
 2 files changed, 45 insertions(+)

diff --git a/stm-init.c b/stm-init.c
index 051a755..0c0fd0f 100644
--- a/stm-init.c
+++ b/stm-init.c
@@ -48,6 +48,9 @@
 /* Private variables ---------------------------------------------------------*/
 
 /* Private function prototypes -----------------------------------------------*/
+#ifdef CRYPTECH_USE_HSE_CLOCK
+static void SystemClock_Config(void);
+#endif
 #ifdef HAL_GPIO_MODULE_ENABLED
 static void MX_GPIO_Init(void);
 #endif
@@ -61,6 +64,10 @@ void stm_init(void)
 
   /* MCU Configuration----------------------------------------------------------*/
 
+#ifdef CRYPTECH_USE_HSE_CLOCK
+  SystemClock_Config();
+#endif
+
   /* System interrupt init*/
   /* Sets the priority grouping field */
   HAL_NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_0);
@@ -76,6 +83,42 @@ void stm_init(void)
 #endif
 }
 
+#ifdef CRYPTECH_USE_HSE_CLOCK
+/** System Clock Configuration
+ *
+ * HSE crystal at 25 MHz, end result is 180 MHz clock.
+ */
+void SystemClock_Config(void)
+{
+  RCC_ClkInitTypeDef RCC_ClkInitStruct;
+  RCC_OscInitTypeDef RCC_OscInitStruct;
+
+  __PWR_CLK_ENABLE();
+
+  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
+
+  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
+  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
+  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
+  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+  RCC_OscInitStruct.PLL.PLLM = 25;
+  RCC_OscInitStruct.PLL.PLLN = 360;
+  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
+  RCC_OscInitStruct.PLL.PLLQ = 4;
+  HAL_RCC_OscConfig(&RCC_OscInitStruct);
+
+  HAL_PWREx_ActivateOverDrive();
+
+  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
+  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
+  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_5);
+}
+#endif
+
+
 #ifdef HAL_UART_MODULE_ENABLED
 /* USART1 init function */
 static void MX_USART1_UART_Init(void)
diff --git a/stm-init.h b/stm-init.h
index ed80d01..489a2c6 100644
--- a/stm-init.h
+++ b/stm-init.h
@@ -43,4 +43,6 @@ extern void Error_Handler(void);
 
 #define HAL_Delay osDelay
 
+#define CRYPTECH_USE_HSE_CLOCK
+
 #endif /* __STM_INIT_H */
-- 
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