原理图：

矩阵按键原理图：

实验板接口原理图：

得到对应图：

扫描按键原理：

按键的COLUMN1、2、3分别制0，每次只允许其中一个为0其他都是1（POW1和POW2正常状况为上拉），当有一个按键按下POW1和POW2必有一个被制0，这样就是能找到按键的标号
所以很明确COLUMN1、2、3应该制为输出电平，而POW1和POW2应该制输入电平用来读取按键被按下而传入的低电平

CubMX配置：

由于OLED引脚被占用所以用串口输出调试

Keil配置：

Function:

#include "Function.h"
#include "usart.h"
#include "gpio.h"

void Function_SendInformation(const char * data, uint16_t len){
	HAL_UART_Transmit(&huart2, data, len, 0xff);
}

void Function_ReciveInformation(char * data, uint16_t len){
	HAL_UART_Receive(&huart2, data, len, 0xff);
}

 
void Function_OnlyRsetPortPin(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin){ // 将其中一个COLUMN制0
	HAL_GPIO_WritePin(COLUMN1_GPIO_Port, COLUMN1_Pin, GPIO_PIN_SET);
	HAL_GPIO_WritePin(COLUMN2_GPIO_Port, COLUMN2_Pin, GPIO_PIN_SET);
	HAL_GPIO_WritePin(COLUMN3_GPIO_Port, COLUMN3_Pin, GPIO_PIN_SET);
	HAL_GPIO_WritePin(GPIOx, GPIO_Pin, GPIO_PIN_RESET);
}

unsigned char Function_ResetPowNumberFind(void){ // 找到哪一根POW线制零了
	if(HAL_GPIO_ReadPin(POW1_GPIO_Port, POW1_Pin) == GPIO_PIN_RESET){ 
		 HAL_Delay(2); // 去抖动
		if(HAL_GPIO_ReadPin(POW1_GPIO_Port, POW1_Pin) == GPIO_PIN_RESET){ // 有效按下
			
			while(HAL_GPIO_ReadPin(POW1_GPIO_Port, POW1_Pin) == GPIO_PIN_RESET); // 按下一直有效
			
			return 1; // 松开放回POW1被制0
		}
	}
	
	if(HAL_GPIO_ReadPin(POW2_GPIO_Port, POW2_Pin) == GPIO_PIN_RESET){ 
		 HAL_Delay(2); // 去抖动
		 if(HAL_GPIO_ReadPin(POW2_GPIO_Port, POW2_Pin) == GPIO_PIN_RESET){ // 有效按下
			
			 while(HAL_GPIO_ReadPin(POW2_GPIO_Port, POW2_Pin) == GPIO_PIN_RESET); // 按下一直有效
			
			 return 2; // 松开放回POW1被按下
		 }
	}
	
	return 0; // 即POW1和POW2都未读取0
}


unsigned char Function_KeyMatrixCheck(void){
	unsigned char PowFind = 0;
	
	Function_OnlyRsetPortPin(COLUMN1_GPIO_Port, COLUMN1_Pin);
  PowFind = Function_ResetPowNumberFind();	
	if(PowFind == 1) return 1;
	else if(PowFind == 2) return 4;
	
	PowFind = 0;
	Function_OnlyRsetPortPin(COLUMN2_GPIO_Port, COLUMN2_Pin);
  PowFind = Function_ResetPowNumberFind();	
	if(PowFind == 1) return 2;
	else if(PowFind == 2) return 5;
	
  PowFind = 0;
	Function_OnlyRsetPortPin(COLUMN3_GPIO_Port, COLUMN3_Pin);
  PowFind = Function_ResetPowNumberFind();	
	if(PowFind == 1) return 3;
	else if(PowFind == 2) return 6;	
}

#ifndef __FUNCTION__
#define __FUNCTION__
#include <stdint.h>

void Function_SendInformation(const char * data, uint16_t len);
void Function_ReciveInformation(char * data, uint16_t len);
unsigned char Function_KeyMatrixCheck(void);
#endif

main:

 
#include "main.h"
#include "usart.h"
#include "gpio.h"
#include "Function.h"

 
void SystemClock_Config(void);
 
int main(void)
{
  
  unsigned char Rx[1];
  
  HAL_Init();

 
  SystemClock_Config();

 
  MX_GPIO_Init();
  MX_USART2_UART_Init();
  
  while (1)
  {
    
		Rx[0] = Function_KeyMatrixCheck();
		if(Rx[0]){ // 返回不是0才输出
      Function_SendInformation(Rx, 1);
		}
		HAL_Delay(1000);
     
  }
 
}

 
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

 
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_4;
  RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_2;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

 
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART2;
  PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}

 
void Error_Handler(void)
{
   
  __disable_irq();
  while (1)
  {
  }
   
}

运行效果：