GD32E103怎么使用外部晶振配置到时钟120M？

只看该作者 · 2020-11-17 20:47

如题，下载了官方的demo，进入main函数没看见有初始化配置时钟的部分，但是却能打印出系统时钟是120Mhz，有摸索过的老铁，如果有空劳您宝贵时间给解答一二
/* configure systick */
systick_config();

/* initilize the LEDs, USART and key */
/* enable the led clock */
rcu_periph_clock_enable(RCU_GPIOB);
/* configure led GPIO port */
gpio_init(GPIOB, GPIO_MODE_OUT_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_12);

gpio_bit_write(GPIOB,GPIO_PIN_12,SET);

gd_eval_com_init(EVAL_COM0);
/* print out the clock frequency of system, AHB, APB1 and APB2 */
printf("\r\nCK_SYS is %d", rcu_clock_freq_get(CK_SYS));
printf("\r\nCK_AHB is %d", rcu_clock_freq_get(CK_AHB));
printf("\r\nCK_APB1 is %d", rcu_clock_freq_get(CK_APB1));
printf("\r\nCK_APB2 is %d", rcu_clock_freq_get(CK_APB2));
main函数在这了，这里打印的信息看到时钟是120Mhz，但是main函数没有任何配置时钟的代码，怎么就直接配置到了120M呢？