NXP i.MX RT1052 RT-Thread实战：新建RT-Thread工程—软件仿真【基于Cortex-M3】

/**************************************************************************//** * @file system_ARMCM3.c * @brief CMSIS Device System Source File for * ARMCM3 Device Series * @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 "ARMCM3.h" /*---------------------------------------------------------------------------- Define clocks *----------------------------------------------------------------------------*/ #define XTAL ( 5000000UL) /* Oscillator frequency */ #define SYSTEM_CLOCK (5U * XTAL) /*---------------------------------------------------------------------------- Externals *----------------------------------------------------------------------------*/ #if defined (__VTOR_PRESENT) && (__VTOR_PRESENT == 1U) extern uint32_t __Vectors; #endif /*---------------------------------------------------------------------------- System Core Clock Variable *----------------------------------------------------------------------------*/ uint32_t SystemCoreClock = SYSTEM_CLOCK; /*---------------------------------------------------------------------------- System Core Clock update function *----------------------------------------------------------------------------*/ void SystemCoreClockUpdate (void) { SystemCoreClock = SYSTEM_CLOCK; } /*---------------------------------------------------------------------------- System initialization function *----------------------------------------------------------------------------*/ void SystemInit (void) { #if defined (__VTOR_PRESENT) && (__VTOR_PRESENT == 1U) SCB->VTOR = (uint32_t) &__Vectors; #endif SystemCoreClock = SYSTEM_CLOCK; }