The. Net Micro Framework Portingkit

On the two "modify startup code & rewrite vector table" SRAM initialization & Set Nvic Interrupt table offset article, we set the interrupt vector table, initialized the RAM, and reset the address of the vector table, this article is a relatively important one, we will set the chip clock.

1. New CortexM3.h header File

Create a new CortexM3.h file in the. \devicecode\targets\native\cortexm3 directory and write the following code:

#ifndef _cortexm3_h_


#define _CORTEXM3_H_1





#include <cores\arm\include\cpu.h>





typedef volatile unsigned long VU32;


typedef volatile unsigned short VU16;


typedef volatile unsigned char VU8;





extern "C"


{


void Bootstrapcode_clocks ();


}





/*------------------------Reset and Clock control---------------------------*/


struct CORTEXM3_RCC


{


static const UINT32 c_base = 0x40021000;





static const UINT8 Flag_hsirdy = ((UINT8) 0x20);


static const UINT8 Flag_hserdy = ((UINT8) 0x31);





/****/volatile UINT32 CR;


static const UINT32 Cr_hsebyp_reset = ((UINT32) 0xFFFBFFFF);


static const UINT32 Cr_hsebyp_set = ((UINT32) 0x00040000);


static const UINT32 Cr_hseon_reset = ((UINT32) 0xFFFEFFFF);


static const UINT32 Cr_hseon_set = ((UINT32) 0x00010000);


static const UINT32 Cr_hsitrim_mask = ((UINT32) 0xffffff07);





/****/volatile UINT32 cfgr;


static const UINT32 CFGR_SYSCLK_DIV1 = ((UINT32) 0x00000000);


static const UINT32 CFGR_SYSCLK_DIV2 = ((UINT32) 0x00000080);


static const UINT32 CFGR_SYSCLK_DIV4 = ((UINT32) 0x00000090);


static const UINT32 CFGR_SYSCLK_DIV8 = ((UINT32) 0x000000a0);


static const UINT32 CFGR_SYSCLK_DIV16 = ((UINT32) 0x000000b0);


static const UINT32 CFGR_HCLK_DIV1 = ((UINT32) 0x00000000);


static const UINT32 CFGR_HCLK_DIV2 = ((UINT32) 0x00000400);


static const UINT32 CFGR_HCLK_DIV4 = ((UINT32) 0x00000500);





//Omitting part of the code ...





/****/volatile UINT32 apb1rstr;


/****/volatile UINT32 ahbenr;


/****/volatile UINT32 bdcr;


/****/volatile UINT32 CSR;





static void Initialize ();


static bool Getflagstatus (UINT8 Flag);


};





struct CortexM3


{


static CORTEXM3_RCC & RCC () {return * (CORTEXM3_RCC *) (size_t) (cortexm3_rcc::c_base);


};





#endif//_cortexm3_h_1