void KEY_Init(void)//接按键的端口初始化程序
{
RCC->APB2ENR|=______________; //使能PORTA时钟
JTAG_Set(SWD_ENABLE);
GPIOA->CRL&=__________________; // PA3设置成下拉输入
GPIOA->CRL|=__________________;
}
void LED_Init(void)//接LED的端口初始化程序
{
RCC->APB2ENR__________________________; //使能PORTB时钟
GPIOB->CRL______________; // PB.1 设置成推挽输出, 50MHz
GPIOB->CRL______________;
GPIOB->ODR _____________________; //LED点亮
}
答案:
1<<2;
0XFFFF0FFF
0X00008000
|=1<<3;
&=0XFFFFFF0F
|=0X00000030
&=∼(1<<1) 或 &=0XFFFD