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CMSIS-Core (Cortex-M)
Version 5.6.0
CMSIS-Core support for Cortex-M processor-based devices
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CMSIS-Core (Cortex-M)
Version 5.6.0
CMSIS-Core support for Cortex-M processor-based devices
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The Startup File startup_<device>.c contains:
The file exists for each supported toolchain and is the only tool-chain specific CMSIS file.
To adapt the file to a new device only the interrupt vector table needs to be extended with the device-specific interrupt handlers. The naming convention for the interrupt handler names are <interrupt_name>_IRQHandler. This table needs to be consistent with IRQn_Type that defines all the IRQ numbers for each interrupt.
Example:
The following example shows the extension of the interrupt vector table for the LPC1100 device family.
A compiler agnostic startup_Device.c Template File for an Armv7-M processor like Cortex-M3 is shown below. The C startup file relys on certain compiler specific preprocessor defines specified in CMSIS compiler headers:
/******************************************************************************
* @file startup_<Device>.c
* @brief CMSIS-Core(M) Device Startup File for
* Device <Device>
* @version V1.0.0
* @date 20. January 2021
******************************************************************************/
/*
* Copyright (c) 2009-2021 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 "<Device>.h"
/*---------------------------------------------------------------------------
External References
*---------------------------------------------------------------------------*/
extern uint32_t __INITIAL_SP;
extern uint32_t __STACK_LIMIT;
#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
extern uint32_t __STACK_SEAL;
#endif
extern __NO_RETURN void __PROGRAM_START(void);
/*---------------------------------------------------------------------------
Internal References
*---------------------------------------------------------------------------*/
__NO_RETURN void Reset_Handler (void);
__NO_RETURN void Default_Handler(void);
/* ToDo: Add Cortex exception handler according the used Cortex-Core */
/*---------------------------------------------------------------------------
Exception / Interrupt Handler
*---------------------------------------------------------------------------*/
/* Exceptions */
void NMI_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void HardFault_Handler (void) __attribute__ ((weak));
void MemManage_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void BusFault_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void UsageFault_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void SecureFault_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void SVC_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void DebugMon_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void PendSV_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
void SysTick_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
/* ToDo: Add your device specific interrupt handler */
void <DeviceInterrupt first>_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
...
void <DeviceInterrupt last>_Handler (void) __attribute__ ((weak, alias("Default_Handler")));
/*----------------------------------------------------------------------------
Exception / Interrupt Vector table
*----------------------------------------------------------------------------*/
#if defined ( __GNUC__ )
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
#endif
/* ToDo: Add Cortex exception vectors according the used Cortex-Core */
extern const VECTOR_TABLE_Type __VECTOR_TABLE[<Device vector table entries>];
const VECTOR_TABLE_Type __VECTOR_TABLE[<Device vector table entries>] __VECTOR_TABLE_ATTRIBUTE = {
(VECTOR_TABLE_Type)(&__INITIAL_SP), /* Initial Stack Pointer */
Reset_Handler, /* Reset Handler */
NMI_Handler, /* -14 NMI Handler */
HardFault_Handler, /* -13 Hard Fault Handler */
MemManage_Handler, /* -12 MPU Fault Handler */
BusFault_Handler, /* -11 Bus Fault Handler */
UsageFault_Handler, /* -10 Usage Fault Handler */
SecureFault_Handler, /* -9 Secure Fault Handler */
0, /* Reserved */
0, /* Reserved */
0, /* Reserved */
SVC_Handler, /* -5 SVCall Handler */
DebugMon_Handler, /* -4 Debug Monitor Handler */
0, /* Reserved */
PendSV_Handler, /* -2 PendSV Handler */
SysTick_Handler, /* -1 SysTick Handler */
/* ToDo: Add your device specific interrupt vectors */
/* Interrupts */
<DeviceInterrupt first>_Handler, /* first Device Interrupt */
...
<DeviceInterrupt last>_Handler /* last Device Interrupt */
};
#if defined ( __GNUC__ )
#pragma GCC diagnostic pop
#endif
/*---------------------------------------------------------------------------
Reset Handler called on controller reset
*---------------------------------------------------------------------------*/
__NO_RETURN void Reset_Handler(void)
{
__set_PSP((uint32_t)(&__INITIAL_SP));
/* ToDo: Initialize stack limit register for Armv8-M Main Extension based processors*/
__set_MSPLIM((uint32_t)(&__STACK_LIMIT));
__set_PSPLIM((uint32_t)(&__STACK_LIMIT));
/* ToDo: Add stack sealing for Armv8-M based processors */
#if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
__TZ_set_STACKSEAL_S((uint32_t *)(&__STACK_SEAL));
#endif
SystemInit(); /* CMSIS System Initialization */
__PROGRAM_START(); /* Enter PreMain (C library entry point) */
}
#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-noreturn"
#endif
/*---------------------------------------------------------------------------
Hard Fault Handler
*---------------------------------------------------------------------------*/
void HardFault_Handler(void)
{
while(1);
}
/*---------------------------------------------------------------------------
Default Handler for Exceptions / Interrupts
*---------------------------------------------------------------------------*/
void Default_Handler(void)
{
while(1);
}
#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050)
#pragma clang diagnostic pop
#endif
The C-startup file for an Armv8-M/v8.1-M processor is similar to the one for an Armv7-M processor except that it offers the possibility of stack sealing for the Main Stack Pointer (MSP). The following preprocessor defines and CMSIS functions are used:
The stack sealing and the initialization fof the Stack Limit register is done in function void Reset_Handler(void):