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本文主要实现以下功能：
系统配置为外部16MHZ时钟，并且PLL到144MHZ； 官方的demo用的阻塞方式点灯，即就是死等，在等待期间mcu干不了其他事情（中断除外），这种方式不太友好，本文使用非阻塞方式点灯； 普通定时器1ms一次中断，为整个系统应用层提供时钟，
代码实现： 1、系统配置为外部16MHZ时钟，并且PLL到144MHZ /**
* [url=home.php?mod=space&uid=247401]@brief[/url] system clock config program
* [url=home.php?mod=space&uid=536309]@NOTE[/url] the system clock is configured as follow:
* - system clock = heck * pll_mult
* - system clock source = pll (hick)
* - heck = 16000000
* - sclk = 144000000
* - ahbdiv = 1
* - ahbclk = 144000000
* - apb2div = 2
* - apb2clk = 72000000
* - apb1div = 2
* - apb1clk = 72000000
* - pll_mult = 9
* - flash_wtcyc = 4 cycle
* @param none
* @retval none
*/
void system_clock_config(void)
{
/* config flash psr register */
flash_psr_set(FLASH_WAIT_CYCLE_4);
/* reset crm */
crm_reset();
crm_clock_source_enable(CRM_CLOCK_SOURCE_HEXT, TRUE);
/* wait till heck is ready */
while(crm_flag_get(CRM_HEXT_STABLE_FLAG) != SET)
{
}
/* config pll clock resource */
crm_pll_config(CRM_PLL_SOURCE_HEXT, CRM_PLL_MULT_9);
/* enable pll */
crm_clock_source_enable(CRM_CLOCK_SOURCE_PLL, TRUE);
/* wait till pll is ready */
while(crm_flag_get(CRM_PLL_STABLE_FLAG) != SET)
{
}
/* config ahbclk */
crm_ahb_div_set(CRM_AHB_DIV_1);
/* config apb2clk */
crm_apb2_div_set(CRM_APB2_DIV_2);
/* config apb1clk */
crm_apb1_div_set(CRM_APB1_DIV_2);
/* enable auto step mode */
crm_auto_step_mode_enable(TRUE);
/* select pll as system clock source */
crm_sysclk_switch(CRM_SCLK_PLL);
/* wait till pll is used as system clock source */
while(crm_sysclk_switch_status_get() != CRM_SCLK_PLL)
{
}
/* disable auto step mode */
crm_auto_step_mode_enable(FALSE);
/* update system_core_clock global variable */
system_core_clock_update();
}
2、定时器3配置为1ms中断一次 static uint32_t SystemTick=0;
void TimerInit(void)
{
crm_periph_clock_enable(CRM_TMR3_PERIPH_CLOCK, TRUE);
tmr_base_init(TMR3, 71, 999); //72000000/72/999
tmr_cnt_dir_set(TMR3, TMR_COUNT_UP);
tmr_interrupt_enable(TMR3, TMR_OVF_INT, TRUE);
/* tmr3 overflow interrupt nvic init */
nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);
nvic_irq_enable(TMR3_GLOBAL_IRQn, 0, 0);
/* enable tmr3 */
tmr_counter_enable(TMR3, TRUE);
}
uint32_t SystemGetTick(void)
{
return SystemTick;
}
void TMR3_GLOBAL_IRQHandler(void)
{
if(tmr_flag_get(TMR3, TMR_OVF_FLAG) != RESET)
{
SystemTick++;
tmr_flag_clear(TMR3, TMR_OVF_FLAG);
}
}
3、非阻塞点灯，500ms闪烁一次 void LedInit(void)
{
gpio_init_type gpio_init_struct;
/* enable the led clock */
crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
/* set default parameter */
gpio_default_para_init(&gpio_init_struct);
/* configure the led gpio */
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
gpio_init_struct.gpio_mode = GPIO_MODE_OUTPUT;
gpio_init_struct.gpio_pins = GPIO_PINS_7|GPIO_PINS_8|GPIO_PINS_9;
gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
gpio_init(GPIOB, &gpio_init_struct);
}
void McuRun(void)
{
static uint32_t curtick=0;
if(SystemGetTick()-curtick>=500)
{
gpio_bits_write(GPIOB, GPIO_PINS_7|GPIO_PINS_8|GPIO_PINS_9, !gpio_output_data_bit_read(GPIOB, GPIO_PINS_7));
curtick=SystemGetTick();
}
}
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