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 <div class="title">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h </div>  </div>
 </div><!--header-->
 <div class="contents">
 <div class="textblock"><p>The <a class="el" href="system_c_pg.html">System Configuration Files system_&lt;device&gt;.c and system_&lt;device&gt;.h</a> provides as a minimum the functions described under <a class="el" href="group__system__init__gr.html">System and Clock Configuration</a>. These functions are device specific and need adaptations. In addition, the file might have configuration settings for the device such as XTAL frequency or PLL prescaler settings.</p>
 <p>For devices with external memory BUS the system_&lt;device&gt;.c also configures the BUS system.</p>
 <p>The silicon vendor might expose other functions (i.e. for power configuration) in the system_&lt;device&gt;.c file. In case of additional features the function prototypes need to be added to the system_&lt;device&gt;.h header file.</p>
 <h1><a class="anchor" id="system_Device_sec"></a>
 system_Device.c Template File</h1>
 <p>The <a class="el" href="system_c_pg.html#system_Device_sec">system_Device.c Template File</a> for the Cortex-M3 is shown below.</p>
 <pre class="fragment">/**************************************************************************//**
  * @file     system_&lt;Device&gt;.c
  * @brief    CMSIS Cortex-M# Device Peripheral Access Layer Source File for
  *           Device &lt;Device&gt;
  * @version  V5.00
  * @date     10. January 2018
  ******************************************************************************/
 /*
  * Copyright (c) 2009-2018 Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the License); you may
  * not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include &lt;stdint.h&gt;
 #include "&lt;Device&gt;.h"


 /*----------------------------------------------------------------------------
   Define clocks
  *----------------------------------------------------------------------------*/
 /* ToDo: add here your necessary defines for device initialization
          following is an example for different system frequencies */
 #define XTAL            (12000000U)       /* Oscillator frequency             */

 #define SYSTEM_CLOCK    (5 * XTAL)


 /*----------------------------------------------------------------------------
   System Core Clock Variable
  *----------------------------------------------------------------------------*/
 /* ToDo: initialize SystemCoreClock with the system core clock frequency value
          achieved after system intitialization.
          This means system core clock frequency after call to SystemInit() */
 uint32_t SystemCoreClock = SYSTEM_CLOCK;  /* System Clock Frequency (Core Clock)*/


 /*----------------------------------------------------------------------------
   Clock functions
  *----------------------------------------------------------------------------*/

 void SystemCoreClockUpdate (void)            /* Get Core Clock Frequency      */
 {
 /* ToDo: add code to calculate the system frequency based upon the current
          register settings.
          This function can be used to retrieve the system core clock frequeny
          after user changed register sittings. */
   SystemCoreClock = SYSTEM_CLOCK;
 }

 void SystemInit (void)
 {
 /* ToDo: add code to initialize the system
          do not use global variables because this function is called before
          reaching pre-main. RW section maybe overwritten afterwards. */
   SystemCoreClock = SYSTEM_CLOCK;
 }
 </pre><h1><a class="anchor" id="system_Device_h_sec"></a>
 system_Device.h Template File</h1>
 <p>The system_&lt;device&gt;.h header file contains prototypes to access the public functions in the system_&lt;device&gt;.c file. The <a class="el" href="system_c_pg.html#system_Device_h_sec">system_Device.h Template File</a> is shown below.</p>
 <pre class="fragment">/**************************************************************************//**
  * @file     system_&lt;Device&gt;.h
  * @brief    CMSIS Cortex-M# Device Peripheral Access Layer Header File for
  *           Device &lt;Device&gt;
  * @version  V5.00
  * @date     10. January 2018
  ******************************************************************************/
 /*
  * Copyright (c) 2009-2018 Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the License); you may
  * not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef SYSTEM_&lt;Device&gt;_H   /* ToDo: replace '&lt;Device&gt;' with your device name */
 #define SYSTEM_&lt;Device&gt;_H

 #ifdef __cplusplus
 extern "C" {
 #endif

 #include &lt;stdint.h&gt;

 extern uint32_t SystemCoreClock;     /*!&lt; System Clock Frequency (Core Clock)  */


 /**
   \brief Setup the microcontroller system.

    Initialize the System and update the SystemCoreClock variable.
  */
 extern void SystemInit (void);


 /**
   \brief  Update SystemCoreClock variable.

    Updates the SystemCoreClock with current core Clock retrieved from cpu registers.
  */
 extern void SystemCoreClockUpdate (void);


 #ifdef __cplusplus
 }
 #endif

 #endif /* SYSTEM_&lt;Device&gt;_H */
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	<div class="header">
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	<div class="title">System Configuration Files system_<device>.c and system_<device>.h </div> </div>
	</div><!--header-->
	<div class="contents">
	<div class="textblock"><p>The <a class="el" href="system_c_pg.html">System Configuration Files system_<device>.c and system_<device>.h</a> provides as a minimum the functions described under <a class="el" href="group__system__init__gr.html">System and Clock Configuration</a>. These functions are device specific and need adaptations. In addition, the file might have configuration settings for the device such as XTAL frequency or PLL prescaler settings.</p>
	<p>For devices with external memory BUS the system_<device>.c also configures the BUS system.</p>
	<p>The silicon vendor might expose other functions (i.e. for power configuration) in the system_<device>.c file. In case of additional features the function prototypes need to be added to the system_<device>.h header file.</p>
	<h1><a class="anchor" id="system_Device_sec"></a>
	system_Device.c Template File</h1>
	<p>The <a class="el" href="system_c_pg.html#system_Device_sec">system_Device.c Template File</a> for the Cortex-M3 is shown below.</p>
	<pre class="fragment">/************************************************************************//
	* @file system_<Device>.c
	* @brief CMSIS Cortex-M# Device Peripheral Access Layer Source File for
	* Device <Device>
	* @version V5.00
	* @date 10. January 2018
	******************************************************************************/
	/*
	* Copyright (c) 2009-2018 Arm Limited. All rights reserved.
	*
	* SPDX-License-Identifier: Apache-2.0
	*
	* Licensed under the Apache License, Version 2.0 (the License); you may
	* not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an AS IS BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <stdint.h>
	#include "<Device>.h"


	/*----------------------------------------------------------------------------
	Define clocks
	----------------------------------------------------------------------------/
	/* ToDo: add here your necessary defines for device initialization
	following is an example for different system frequencies */
	#define XTAL (12000000U) /* Oscillator frequency */

	#define SYSTEM_CLOCK (5 * XTAL)


	/*----------------------------------------------------------------------------
	System Core Clock Variable
	----------------------------------------------------------------------------/
	/* ToDo: initialize SystemCoreClock with the system core clock frequency value
	achieved after system intitialization.
	This means system core clock frequency after call to SystemInit() */
	uint32_t SystemCoreClock = SYSTEM_CLOCK; /* System Clock Frequency (Core Clock)*/



	/*----------------------------------------------------------------------------
	Clock functions
	----------------------------------------------------------------------------/

	void SystemCoreClockUpdate (void) /* Get Core Clock Frequency */
	{
	/* ToDo: add code to calculate the system frequency based upon the current
	register settings.
	This function can be used to retrieve the system core clock frequeny
	after user changed register sittings. */
	SystemCoreClock = SYSTEM_CLOCK;
	}

	void SystemInit (void)
	{
	/* ToDo: add code to initialize the system
	do not use global variables because this function is called before
	reaching pre-main. RW section maybe overwritten afterwards. */
	SystemCoreClock = SYSTEM_CLOCK;
	}
	</pre><h1><a class="anchor" id="system_Device_h_sec"></a>
	system_Device.h Template File</h1>
	<p>The system_<device>.h header file contains prototypes to access the public functions in the system_<device>.c file. The <a class="el" href="system_c_pg.html#system_Device_h_sec">system_Device.h Template File</a> is shown below.</p>
	<pre class="fragment">/************************************************************************//
	* @file system_<Device>.h
	* @brief CMSIS Cortex-M# Device Peripheral Access Layer Header File for
	* Device <Device>
	* @version V5.00
	* @date 10. January 2018
	******************************************************************************/
	/*
	* Copyright (c) 2009-2018 Arm Limited. All rights reserved.
	*
	* SPDX-License-Identifier: Apache-2.0
	*
	* Licensed under the Apache License, Version 2.0 (the License); you may
	* not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an AS IS BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef SYSTEM_<Device>_H /* ToDo: replace '<Device>' with your device name */
	#define SYSTEM_<Device>_H

	#ifdef __cplusplus
	extern "C" {
	#endif

	#include <stdint.h>

	extern uint32_t SystemCoreClock; /!< System Clock Frequency (Core Clock) /


	/**
	\brief Setup the microcontroller system.

	Initialize the System and update the SystemCoreClock variable.
	*/
	extern void SystemInit (void);


	/**
	\brief Update SystemCoreClock variable.

	Updates the SystemCoreClock with current core Clock retrieved from cpu registers.
	*/
	extern void SystemCoreClockUpdate (void);


	#ifdef __cplusplus
	}
	#endif

	#endif /* SYSTEM_<Device>_H */
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