为了实现计算器键盘，需要使用4X5矩阵按键，因此，我在4X4矩阵键盘上重新设计了一个4X5矩阵按键。原理图如下：
原理描述：
4X5矩阵按键，可以设置4个引脚为输出，5个引脚为输入模式，4个引脚依次设置为低电平，5个引脚依次扫描读取电平变化，如果为低电平，则表示按键按下，这样就可以通过坐标算出按键的位置（二维矩阵坐标）。
设计的PCB板如下：
3D效果图如下：
实物图：
接线表如下：
| 矩阵按键 | STM32 | |
| R5 | PA15 | 上拉输入模式 |
| R4 | PB12 | 上拉输入模式 |
| R3 | PB13 | 上拉输入模式 |
| R2 | PB14 | 上拉输入模式 |
| R1 | PB15 | 上拉输入模式 |
| C1 | PA8 | 推挽输出模式 |
| C2 | PA9 | 推挽输出模式 |
| C3 | PA10 | 推挽输出模式 |
| C4 | PA11 | 推挽输出模式 |
| - | PA2 | USART2_TX |
| - | PA3 | USART2_RX |
功能：
将按键的信息在串口2显示，和博客原理一致：
4X4矩阵按键实现，博客地址：
STM32CubeMX实现矩阵按键（HAL库实现）_使用hal库使用矩阵按键-CSDN博客
CubeMX配置过程如下：
注意：这里需要注意一下，如果用STM32F103C8T6最小系统USB供电，PA12口不能作为普通的输入输出口，因为该口与USB相接，导致电平混乱。
代码如下：
按键扫描：
/* USER CODE BEGIN 0 */
uint16_t keyScan(void)
{
HAL_GPIO_WritePin(GPIOA, COL1_Pin, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOA, COL2_Pin|COL3_Pin|COL4_Pin, GPIO_PIN_SET);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 4\r\n", 8, 0XFFFF);
return 20;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 4\r\n", 8, 0XFFFF);
return 4;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 8\r\n", 8, 0XFFFF);
return 8;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 12\r\n", 9, 0XFFFF);
return 12;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 16\r\n", 9, 0XFFFF);
return 16;
}
HAL_GPIO_WritePin(GPIOA, COL2_Pin, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOA, COL1_Pin|COL3_Pin|COL4_Pin, GPIO_PIN_SET);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 4\r\n", 8, 0XFFFF);
return 19;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 3\r\n", 9, 0XFFFF);
return 3;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 7\r\n", 9, 0XFFFF);
return 7;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 11\r\n", 9, 0XFFFF);
return 11;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 15\r\n", 9, 0XFFFF);
return 15;
}
HAL_GPIO_WritePin(GPIOA, COL3_Pin, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOA, COL1_Pin|COL2_Pin|COL4_Pin, GPIO_PIN_SET);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 4\r\n", 8, 0XFFFF);
return 18;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 2\r\n", 9, 0XFFFF);
return 2;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 6\r\n", 9, 0XFFFF);
return 6;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 10\r\n", 9, 0XFFFF);
return 10;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 14\r\n", 9, 0XFFFF);
return 14;
}
HAL_GPIO_WritePin(GPIOA, COL4_Pin, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOA, COL1_Pin|COL2_Pin|COL3_Pin, GPIO_PIN_SET);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOA, ROW5_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 4\r\n", 8, 0XFFFF);
return 17;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW4_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 1\r\n", 9, 0XFFFF);
return 1;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW3_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 5\r\n", 9, 0XFFFF);
return 5;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW2_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 9\r\n", 9, 0XFFFF);
return 9;
}
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_Delay(20);
if(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin))
{
HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
}
while(GPIO_PIN_RESET == HAL_GPIO_ReadPin(GPIOB, ROW1_Pin));
//HAL_UART_Transmit(&huart2, (uint8_t *)"key: 13\r\n", 9, 0XFFFF);
return 13;
}
return 0;
}
/* USER CODE END 0 */主函数：
int main(void)
{
/* USER CODE BEGIN 1 */
uint16_t keyValue = 0; // 按键返回的键值
uint8_t str[10] = "";
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
HAL_GPIO_WritePin(GPIOA, COL1_Pin|COL2_Pin|COL3_Pin|COL4_Pin, GPIO_PIN_SET); // 初始化高电平
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
if((keyValue = keyScan()) !=0 )
{
sprintf((char*)str,"key: %d\r\n",keyValue);
HAL_UART_Transmit(&huart2, str, strlen((char*)str), 0XFFFF);
}
}
/* USER CODE END 3 */
}实现效果，如下：
代码并不是很复杂。
代码如下：
STM32CubeMX实现4X5矩阵按键（HAL库实现）资源-CSDN文库
