主程序如下：
u8 key_num = 0; int main (void) { uart_init(115200); delay_init(); KEY44_Init(); while(1) { key_num = key44_Scan(); if(key_num != 0) { printf("Key Num is %d\r\n",key_num); } } } void KEY44_Init(void) { GPIO_InitTypeDef GPIO_InitStructure;//结构体声明 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);//使能APB2外设时钟 GPIO_InitStructure.GPIO_Pin = (GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3);//选用管脚1,2,3 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//设置管脚的速率 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//设置管脚为推挽式输出 GPIO_Init(GPIOA, &GPIO_InitStructure); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE); GPIO_InitStructure.GPIO_Pin = (GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7);//选用管脚5,6,7 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;//设置管脚为上拉式输入unsigned char key44_Scan(void) { H_1 = 0; H_2 = 1; H_3 = 1; H_4 = 1; if(L_1 == 0) { delay_ms(10); if(L_1 == 0) { while(!L_1); return 1; } } if(L_2 == 0) { delay_ms(10); if(L_2 == 0) { while(!L_2); return 2; } } if(L_3 == 0) { delay_ms(10); if(L_3 == 0) { while(!L_3); return 3; } } if(L_4 == 0) { delay_ms(10); if(L_4 == 0) { while(!L_4); return 4; } } H_1 = 1; H_2 = 0; H_3 = 1; H_4 = 1; if(L_1 == 0) { delay_ms(10); if(L_1 == 0) { while(!L_1); return 5; } } if(L_2 == 0) { delay_ms(10); if(L_2 == 0) { while(!L_2); return 6; } } if(L_3 == 0) { delay_ms(10); if(L_3 == 0) { while(!L_3); return 7; } } if(L_4 == 0) { delay_ms(10); if(L_4 == 0) { while(!L_4); return 8; } } H_1 = 1; H_2 = 1; H_3 = 0; H_4 = 1; if(L_1 == 0) { delay_ms(10); if(L_1 == 0) { while(!L_1); return 9; } } if(L_2 == 0) { delay_ms(10); if(L_2 == 0) { while(!L_2); return 10; } } if(L_3 == 0) { delay_ms(10); if(L_3 == 0) { while(!L_3); return 11; } } if(L_4 == 0) { delay_ms(10); if(L_4 == 0) { while(!L_4); return 12; } } H_1 = 1; H_2 = 1; H_3 = 1; H_4 = 0; if(L_1 == 0) { delay_ms(10); if(L_1 == 0) { while(!L_1); return 13; } } if(L_2 == 0) { delay_ms(10); if(L_2 == 0) { while(!L_2); return 14; } } if(L_3 == 0) { delay_ms(10); if(L_3 == 0) { while(!L_3); return 15; } } if(L_4 == 0) { delay_ms(10); if(L_4 == 0) { while(!L_4); return 16; } } return 0; }void uart_init(u32 bound) { //GPIO端口设置 GPIO_InitTypeDef GPIO_InitStructure; USART_InitTypeDef USART_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART3|RCC_APB2Periph_GPIOA, ENABLE); //使能USART3，GPIOA时钟 USART_DeInit(USART3); //复位串口3 //USART1_TX PA.9 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出 GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化PA9 //USART1_RX PA.10 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入 GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化PA10 //Usart1 NVIC 配置 NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;//抢占优先级3 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //子优先级3 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能 NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器 //USART 初始化设置 USART_InitStructure.USART_BaudRate = bound;//一般设置为115200; USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式 USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个停止位 USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位 USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制 USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收发模式 USART_Init(USART1, &USART_InitStructure); //初始化串口 USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//开启中断 USART_Cmd(USART1, ENABLE); //使能串口 } #if EN_USART1_RX //如果使能了接收 void USART1_IRQHandler(void) //串口3中断服务程序 { u8 Res; #ifdef OS_TICKS_PER_SEC //如果时钟节拍数定义了,说明要使用ucosII了. OSIntEnter(); #endif if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET) //接收中断(接收到的数据必须是0x0d 0x0a结尾) { Res =USART_ReceiveData(USART3);//(USART3->DR); //读取接收到的数据 if((USART_RX_STA&0x8000)==0)//接收未完成 { if(USART_RX_STA&0x4000)//接收到了0x0d { if(Res!=0x0a)USART_RX_STA=0;//接收错误,重新开始 else USART_RX_STA|=0x8000; //接收完成了 } else //还没收到0X0D { if(Res==0x0d)USART_RX_STA|=0x4000; else { USART_RX_BUF[USART_RX_STA&0X3FFF]=Res ; USART_RX_STA++; if(USART_RX_STA>(USART_REC_LEN-1))USART_RX_STA=0;//接收数据错误,重新开始接收 } } } } 文章来源: 矩阵键盘通过串口3输出