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分亨一下龙丘的K60超频函数:
//锁相环频率为50/12*54=225M测试函数
void pllinit225M(void)
{
uint32_t temp_reg;
//使能IO端口时钟
SIM_SCGC5 |= (SIM_SCGC5_PORTA_MASK | SIM_SCGC5_PORTB_MASK | SIM_SCGC5_PORTC_MASK |
SIM_SCGC5_PORTD_MASK | SIM_SCGC5_PORTE_MASK );
//这里处在默认的FEI模式
//首先移动到FBE模式
MCG_C2 = 0;
//初始化晶振后释放锁定状态的振荡器和GPIO
SIM_SCGC4 |= SIM_SCGC4_LLWU_MASK;
LLWU_CS |= LLWU_CS_ACKISO_MASK;
//选择外部晶振，参考分频器，清IREFS来启动外部晶振
//011 If RANGE = 0, Divide Factor is 8; for all other RANGE values, Divide Factor is 256.
MCG_C1 = MCG_C1_CLKS(2) | MCG_C1_FRDIV(3);
//等待晶振稳定
while (MCG_S & MCG_S_IREFST_MASK){} //等待时钟切换到外部参考时钟
while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x2){}
//进入FBE模式,
//0x18==25分频=2M,
//0x08==15分频=3.333M
//0x09==16分频=3.125M,
//0x10==17分频=2.94M
//0x11==18分频=2.7778M
//0x12==19分频=2.63M,
//0x13==20分频=2.5M
MCG_C5 = MCG_C5_PRDIV(0x0b);
//确保MCG_C6处于复位状态，禁止LOLIE、PLL、和时钟控制器，清PLL VCO分频器
MCG_C6 = 0x0;
//保存FMC_PFAPR当前的值
temp_reg = FMC_PFAPR;
//通过M&PFD置位M0PFD来禁止预取功能
FMC_PFAPR |= FMC_PFAPR_M7PFD_MASK | FMC_PFAPR_M6PFD_MASK | FMC_PFAPR_M5PFD_MASK
| FMC_PFAPR_M4PFD_MASK | FMC_PFAPR_M3PFD_MASK | FMC_PFAPR_M2PFD_MASK
| FMC_PFAPR_M1PFD_MASK | FMC_PFAPR_M0PFD_MASK;
///设置系统分频器
//MCG=PLL, core = MCG, bus = MCG/3, FlexBus = MCG/3, Flash clock= MCG/9
SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1(0) | SIM_CLKDIV1_OUTDIV2(2)
| SIM_CLKDIV1_OUTDIV3(2) | SIM_CLKDIV1_OUTDIV4(8);
//从新存FMC_PFAPR的原始值
FMC_PFAPR = temp_reg;
//设置VCO分频器，使能PLL为100MHz, LOLIE=0, PLLS=1, CME=0, VDIV=26
MCG_C6 = MCG_C6_PLLS_MASK | MCG_C6_VDIV(30); //VDIV = 31 (x54)
//VDIV = 26 (x50)
while (!(MCG_S & MCG_S_PLLST_MASK)){}; // wait for PLL status bit to set
while (!(MCG_S & MCG_S_LOCK_MASK)){}; // Wait for LOCK bit to set
//进入PBE模式
//通过清零CLKS位来进入PEE模式
// CLKS=0, FRDIV=3, IREFS=0, IRCLKEN=0, IREFSTEN=0
MCG_C1 &= ~MCG_C1_CLKS_MASK;
//等待时钟状态位更新
while (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) != 0x3){};
//SIM_CLKDIV2 |= SIM_CLKDIV2_USBDIV(1);
//设置跟踪时钟为内核时钟
SIM_SOPT2 |= SIM_SOPT2_TRACECLKSEL_MASK;
//在PTA6引脚上使能TRACE_CLKOU功能
PORTA_PCR6 = ( PORT_PCR_MUX(0x7));
//使能FlexBus模块时钟
SIM_SCGC7 |= SIM_SCGC7_FLEXBUS_MASK;
//在PTA6引脚上使能FB_CLKOUT功能
PORTC_PCR3 = ( PORT_PCR_MUX(0x5));
}
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发表于 2014-5-9 22:30:48
和K60的超频相比，老产品真是悲剧啊。
楼主
