第十一届蓝桥杯嵌入式组别底层驱动程序-拓展板（矩阵）
扩展板的8个按键根据AD采样到相应引脚的电压来判断是哪一按键
扩展版按键通过跳线帽将PA5与AKEY相连
#include "button.h"
void button_Init()
{
ADC_InitTypeDef ADC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOA, &GPIO_InitStructure);
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1;
ADC_Init(ADC1, &ADC_InitStructure);
ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 1, ADC_SampleTime_55Cycles5);
ADC_Cmd(ADC1, ENABLE);
ADC_ResetCalibration(ADC1);
while(ADC_GetResetCalibrationStatus(ADC1));
ADC_StartCalibration(ADC1);
while(ADC_GetCalibrationStatus(ADC1));
}
u8 get_button()
{
u16 btn_tmp;
ADC_SoftwareStartConvCmd(ADC1, ENABLE);
while(!ADC_GetFlagStatus( ADC1, ADC_FLAG_EOC));
btn_tmp=ADC_GetConversionValue(ADC1);
if(btn_tmp <= 0x0020)
{
return 1;
}
else if((btn_tmp >= 0x00B0) && (btn_tmp <= 0x0100))
{
return 2;
}
else if((btn_tmp >= 0x0240) && (btn_tmp <= 0x0300))
{
return 3;
}
else if((btn_tmp >= 0x03B0) && (btn_tmp <= 0x0450))
{
return 4;
}
else if((btn_tmp >= 0x0450) && (btn_tmp <= 0x0700))
{
return 5;
}
else if((btn_tmp >= 0x0700) && (btn_tmp <= 0x0800))
{
return 6;
}
else if((btn_tmp >= 0x0840) && (btn_tmp <= 0x0940))
{
return 7;
}
else if(btn_tmp <= 0x0B50)
{
return 8;
}
else
{
return 0; //error status & no key
}
}
uint8_t button_dat = 0;
//矩阵
button_Init();
button_dat = get_button();//按键按下之后的返回值
snprintf((char *)str, sizeof(str), " %.2d", button_dat);
LCD_DisplayStringLine(Line9, str);
原文链接：https://blog.csdn.net/Zach_z/article/details/80548423