IAR是5.30版本，从官网上下的基于UCOSII2.84版本的移植范例（LPC2378），用J-LINK V6调试，为了节省空间，优化选项选择最高程度的代码量优化（之前选不优化，结果也是跑飞），结果发现在这里会跑飞（在flash中调，开发板SmartARM2300）
static void Tmr_TickInit (void)
{
CPU_INT32U pclk_freq;
CPU_INT32U rld_cnts;
/* VIC timer #0 Initialization */
VICIntSelect &= ~(1 << VIC_TIMER0); /* Configure the timer interrupt as an IRQ source */
VICVectAddr4 = (CPU_INT32U)Tmr_TickISR_Handler; /* Set the vector address */
VICIntEnable = (1 << VIC_TIMER0); /* Enable the timer interrupt source */
pclk_freq = BSP_CPU_PclkFreq(PCLK_TIMER0); /* Get the peripheral clock frequency */
rld_cnts = pclk_freq / OS_TICKS_PER_SEC; /* Calculate the # of counts necessary for the OS ticker */
T0TCR = (1 << 1); /* Disable and reset counter 0 and the prescale counter 0 */
T0TCR = 0; /* Clear the reset bit */
T0PC = 0; /* Prescaler is set to no division */
T0MR0 = rld_cnts;
T0MCR = 3; /* Interrupt on MR0 (reset TC), stop TC */
T0CCR = 0; /* Capture is disabled. */
T0EMR = 0; /* No external match output. */
T0TCR = 1; /* Enable timer 0 */
}
就是在上面这个函数的pclk_freq = BSP_CPU_PclkFreq(PCLK_TIMER0);这一行，并且按F11跟进去，发现这个函数：
CPU_INT32U BSP_CPU_ClkFreq (void)
{
CPU_INT32U msel;
CPU_INT32U nsel=0x10000000;
CPU_INT32U fin;
CPU_INT32U pll_clk_feq; /* When the PLL is enabled, this is Fcco */
CPU_INT32U clk_div;
CPU_INT32U clk_freq;
switch (CLKSRCSEL & 0x03) { /* Determine the current clock source */
case 0:
fin = IRC_OSC_FRQ;
break;
case 1:
fin = MAIN_OSC_FRQ;
break;
case 2:
fin = RTC_OSC_FRQ;
break;
default:
fin = IRC_OSC_FRQ;
break;
}
if ((PLLSTAT & (1 << 25)) > 0) { /* If the PLL is currently enabled and connected */
msel = (CPU_INT32U)(PLLSTAT & 0x3FFF) + 1; /* Obtain the PLL multiplier */
nsel = (CPU_INT32U)((PLLSTAT >> 16) & 0x0F) + 1; /* Obtain the PLL divider */
pll_clk_feq = (2 * msel * (fin / nsel)); /* Compute the PLL output frequency */
} else {
pll_clk_feq = (fin); /* The PLL is bypassed */
}
clk_div = (CPU_INT32U)(CCLKCFG & 0xFF) + 1; /* Obtain the CPU core clock divider */
clk_freq = (CPU_INT32U)(pll_clk_feq / clk_div); /* Compute the ARM Core clock frequency */
return (clk_freq);
}
跟踪到nsel = (CPU_INT32U)((PLLSTAT >> 16) & 0x0F) + 1;这一行时候，发现nsel为unavailable，即使在这之前已经给nsel取了0作为初值。在这一行再往下跟，就飞了。 |
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