| falleaf |
17-01-2008 12:42 PM |
Lôi System.h ra coi chơi nhỉ :)
Code:
/********************************************************************
* FileName: System.h
* Dependencies:
* Processor: PIC32
* Hardware: N/A
* Assembler: N/A
* Linker: N/A
* Company: Microchip Technology, Inc.
********************************************************************/
#ifndef _SYSTEM_HEADER_FILE
#define _SYSTEM_HEADER_FILE
#include <p32xxxx.h>
#include <peripheral/int.h>
#include <peripheral/pcache.h>
#include <peripheral/osc.h>
#include <peripheral/dma.h>
#include <peripheral/bmx.h>
#include <peripheral/lock.h>
#define FLASH_ACCESS_TIME_HZ 20000000
#define PB_BUS_ACCESS_TIME_HZ 50000000
Code:
/*********************************************************************
* Function: void SYSTEMConfigPB(unsigned int sys_clock)
*
* PreCondition: None
*
* Input: sys_clock - system clock in Hz
*
* Output: the PB divider value
*
* Side Effects: Sets the PB divider to the optimum value
********************************************************************/
extern inline unsigned int __attribute__((always_inline)) SYSTEMConfigPB(unsigned int sys_clock)
{
unsigned int dma_status;
unsigned int int_status;
unsigned int pb_clock;
pb_clock = sys_clock;
mSYSTEMUnlock(int_status, dma_status);
// set the PB Div
if(sys_clock > PB_BUS_ACCESS_TIME_HZ)
{
mOSCSetPBDIV(OSC_PB_DIV_2);
pb_clock >>= 1;
}
else
{
mOSCSetPBDIV(OSC_PB_DIV_1);
}
mSYSTEMLock(int_status, dma_status);
return pb_clock;
}
Code:
/*********************************************************************
* Function: void SYSTEMConfigWaitStatesAndPB(unsigned int sys_clock)
*
* PreCondition: None
*
* Input: sys_clock - system clock in Hz
*
* Output: None
*
* Side Effects: Sets the PB and Flash Wait states
********************************************************************/
extern inline unsigned int __attribute__((always_inline)) SYSTEMConfigWaitStatesAndPB(unsigned int sys_clock)
{
#ifdef _PCACHE
unsigned int wait_states;
#endif
unsigned int pb_clock;
unsigned int int_status;
pb_clock = SYSTEMConfigPB(sys_clock);
// set the flash wait states based on 1 wait state
// for every 25 MHz
#ifdef _PCACHE
wait_states = 0;
while(sys_clock >= FLASH_ACCESS_TIME_HZ)
{
wait_states++;
sys_clock -= FLASH_ACCESS_TIME_HZ;
}
int_status=INTDisableInterrupts();
mCheConfigure(wait_states);
INTRestoreInterrupts(int_status);
#endif
return pb_clock;
}
Code:
/*********************************************************************
* Function: void SYSTEMConfigPerformance(unsigned int sys_clock, unsigned int flag)
*
* PreCondition: None
*
* Input: sys_clock - system clock in Hz
*
* Output: None
*
* Side Effects: Sets the PB and Flash Wait states
********************************************************************/
extern inline unsigned int __attribute__((always_inline)) SYSTEMConfigPerformance(unsigned int sys_clock)
{
// set up the wait states
unsigned int pb_clk;
#ifdef _PCACHE
unsigned int cache_status;
#endif
unsigned int int_status;
pb_clk = SYSTEMConfigWaitStatesAndPB(sys_clock);
int_status=INTDisableInterrupts();
mBMXDisableDRMWaitState();
#ifdef _PCACHE
cache_status = mCheGetCon();
cache_status |= CHE_CONF_PF_ALL;
mCheConfigure(cache_status);
CheKseg0CacheOn();
#endif
INTRestoreInterrupts(int_status);
return pb_clk;
}
#endif
Cái chúng ta dùng là cái hàm SYSTEMConfigPerformance cuối cùng này. Có đồng chí nào phân tích cái này giúp F với.
Chúc vui |
