单片机用ADC+电阻扫描键盘的源程序和原理图 -

/************* 本程序功能说明 **************
用STC的MCU的IO方式控制74HC595驱动8位数码管。
显示效果为: 数码时钟.
使用Timer0的16位自动重装来产生1ms节拍,程序运行于这个节拍下, 用户修改MCU主时钟频率时,自动定时于1ms.
左边4位LED显示时间(小时,分钟), 右边最后两位显示按键值.
ADC按键键码为1~16.
按键只支持单键按下, 不支持多键同时按下, 那样将会有不可预知的结果.
键按下超过1秒后,将以10键/秒的速度提供重键输出. 用户只需要检测KeyCode是否非0来判断键是否按下.
调整时间键:
键码1: 小时+.
键码2: 小时-.
键码3: 分钟+.
键码4: 分钟-.
******************************************/
#include "reg51.h"
#include "intrins.h"
#define MAIN_Fosc 11059200L //定义主时钟
typedef unsigned char u8;
typedef unsigned int u16;
typedef unsigned long u32;
sfr TH2 = 0xD6;
sfr TL2 = 0xD7;
sfr IE2 = 0xAF;
sfr INT_CLKO = 0x8F;
sfr AUXR = 0x8E;
sfr AUXR1 = 0xA2;
sfr P_SW1 = 0xA2;
sfr P_SW2 = 0xBA;
sfr S2CON = 0x9A;
sfr S2BUF = 0x9B;
sfr ADC_CONTR = 0xBC; //带AD系列
sfr ADC_RES = 0xBD; //带AD系列
sfr ADC_RESL = 0xBE; //带AD系列
sfr P1ASF = 0x9D; //只写，模拟输入(AD或LVD)选择
sfr P4 = 0xC0;
sfr P5 = 0xC8;
sfr P6 = 0xE8;
sfr P7 = 0xF8;
sfr P1M1 = 0x91; //PxM1.n,PxM0.n =00--->Standard, 01--->push-pull
sfr P1M0 = 0x92; // =10--->pure input, 11--->open drain
sfr P0M1 = 0x93;
sfr P0M0 = 0x94;
sfr P2M1 = 0x95;
sfr P2M0 = 0x96;
sfr P3M1 = 0xB1;
sfr P3M0 = 0xB2;
sfr P4M1 = 0xB3;
sfr P4M0 = 0xB4;
sfr P5M1 = 0xC9;
sfr P5M0 = 0xCA;
sfr P6M1 = 0xCB;
sfr P6M0 = 0xCC;
sfr P7M1 = 0xE1;
sfr P7M0 = 0xE2;
sbit P00 = P0^0;
sbit P01 = P0^1;
sbit P02 = P0^2;
sbit P03 = P0^3;
sbit P04 = P0^4;
sbit P05 = P0^5;
sbit P06 = P0^6;
sbit P07 = P0^7;
sbit P10 = P1^0;
sbit P11 = P1^1;
sbit P12 = P1^2;
sbit P13 = P1^3;
sbit P14 = P1^4;
sbit P15 = P1^5;
sbit P16 = P1^6;
sbit P17 = P1^7;
sbit P20 = P2^0;
sbit P21 = P2^1;
sbit P22 = P2^2;
sbit P23 = P2^3;
sbit P24 = P2^4;
sbit P25 = P2^5;
sbit P26 = P2^6;
sbit P27 = P2^7;
sbit P30 = P3^0;
sbit P31 = P3^1;
sbit P32 = P3^2;
sbit P33 = P3^3;
sbit P34 = P3^4;
sbit P35 = P3^5;
sbit P36 = P3^6;
sbit P37 = P3^7;
sbit P40 = P4^0;
sbit P41 = P4^1;
sbit P42 = P4^2;
sbit P43 = P4^3;
sbit P44 = P4^4;
sbit P45 = P4^5;
sbit P46 = P4^6;
sbit P47 = P4^7;
sbit P50 = P5^0;
sbit P51 = P5^1;
sbit P52 = P5^2;
sbit P53 = P5^3;
sbit P54 = P5^4;
sbit P55 = P5^5;
sbit P56 = P5^6;
sbit P57 = P5^7;
#define Timer0_Reload (65536UL -(MAIN_Fosc / 1000)) //Timer 0 中断频率, 1000次/秒
#define DIS_DOT 0x20
#define DIS_BLACK 0x10
#define DIS_ 0x11
u8 code t_display[]={ //标准字库
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71,
//black - H J K L N o P U t G Q r M y
0x00,0x40,0x76,0x1E,0x70,0x38,0x37,0x5C,0x73,0x3E,0x78,0x3d,0x67,0x50,0x37,0x6e,
0xBF,0x86,0xDB,0xCF,0xE6,0xED,0xFD,0x87,0xFF,0xEF,0x46}; //0. 1. 2. 3. 4. 5. 6. 7. 8. 9. -1
u8 code T_COM[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80}; //位码
sbit P_HC595_SER = P4^0; //pin 14 SER data input
sbit P_HC595_RCLK = P5^4; //pin 12 RCLk store (latch) clock
sbit P_HC595_SRCLK = P4^3; //pin 11 SRCLK Shift data clock
u8 LED8[8]; //显示缓冲
u8 display_index; //显示位索引
bit B_1ms; //1ms标志
u8 ADC_KeyState,ADC_KeyState1,ADC_KeyState2,ADC_KeyState3; //键状态
u8 ADC_KeyHoldCnt; //键按下计时
u8 KeyCode; //给用户使用的键码, 1~16有效
u8 cnt10ms;
u8 hour,minute,second; //RTC变量
u16 msecond;
void CalculateAdcKey(u16 adc);
u16 Get_ADC10bitResult(u8 channel); //channel = 0~7
void DisplayRTC(void);
void RTC(void);
/**********************************************/
void main(void)
{
u8 i;
u16 j;
P0M1 = 0; P0M0 = 0; //设置为准双向口
P1M1 = 0; P1M0 = 0; //设置为准双向口
P2M1 = 0; P2M0 = 0; //设置为准双向口
P3M1 = 0; P3M0 = 0; //设置为准双向口
P4M1 = 0; P4M0 = 0; //设置为准双向口
P5M1 = 0; P5M0 = 0; //设置为准双向口
P6M1 = 0; P6M0 = 0; //设置为准双向口
P7M1 = 0; P7M0 = 0; //设置为准双向口
display_index = 0;
P1ASF = 0x10; //P1.4做ADC
ADC_CONTR = 0xE0; //90T, ADC power on
AUXR = 0x80; //Timer0 set as 1T, 16 bits timer auto-reload,
TH0 = (u8)(Timer0_Reload / 256);
TL0 = (u8)(Timer0_Reload % 256);
ET0 = 1; //Timer0 interrupt enable
TR0 = 1; //Tiner0 run
EA = 1; //打开总中断
for(i=0; i<8; i++) LED8[i] = 0x10; //上电消隐
hour = 12; //初始化时间值
minute = 0;
second = 0;
DisplayRTC();
ADC_KeyState = 0;
ADC_KeyState1 = 0;
ADC_KeyState2 = 0;
ADC_KeyState3 = 0; //键状态
ADC_KeyHoldCnt = 0; //键按下计时
KeyCode = 0; //给用户使用的键码, 1~16有效
cnt10ms = 0;
while(1)
{
if(B_1ms) //1ms到
{
B_1ms = 0;
if(++msecond >= 1000) //1秒到
{
msecond = 0;
RTC();
DisplayRTC();
}
if(msecond == 500) DisplayRTC(); //小时后的小数点做秒闪
if(++cnt10ms >= 10) //10ms读一次ADC
{
cnt10ms = 0;
j = Get_ADC10bitResult(4); //参数0~7,查询方式做一次ADC, 返回值就是结果, == 1024 为错误
if(j < 1024) CalculateAdcKey(j); //计算按键
}
if(KeyCode > 0) //有键按下
{
LED8[6] = KeyCode / 10; //显示键码
LED8[7] = KeyCode % 10; //显示键码
if(KeyCode == 1) //hour +1
{
if(++hour >= 24) hour = 0;
DisplayRTC();
}
if(KeyCode == 2) //hour -1
{
if(--hour >= 24) hour = 23;
DisplayRTC();
}
if(KeyCode == 3) //minute +1
{
second = 0;
if(++minute >= 60) minute = 0;
DisplayRTC();
}
if(KeyCode == 4) //minute -1
{
second = 0;
if(--minute >= 60) minute = 59;
DisplayRTC();
}
KeyCode = 0;
}
}
}
}
/**********************************************/
/********************** 显示时钟函数 ************************/
void DisplayRTC(void)
{
if(hour >= 10) LED8[0] = hour / 10;
else LED8[0] = DIS_BLACK;
LED8[1] = hour % 10;
LED8[2] = minute / 10;
LED8[3] = minute % 10;
if(msecond >= 500) LED8[1] |= DIS_DOT; //小时后的小数点做秒闪
}
/********************** RTC演示函数 ************************/
void RTC(void)
{
if(++second >= 60)
{
second = 0;
if(++minute >= 60)
{
minute = 0;
if(++hour >= 24) hour = 0;
}
}
}
//========================================================================
// 函数: u16 Get_ADC10bitResult(u8 channel)
// 描述: 查询法读一次ADC结果.
// 参数: channel: 选择要转换的ADC.
// 返回: 10位ADC结果.
// 版本: V1.0, 2012-10-22
//========================================================================
u16 Get_ADC10bitResult(u8 channel) //channel = 0~7
{
ADC_RES = 0;
ADC_RESL = 0;
ADC_CONTR = (ADC_CONTR & 0xe0) | 0x08 | channel; //start the ADC
_nop_();
_nop_();
_nop_();
_nop_();
while((ADC_CONTR & 0x10) == 0) ; //wait for ADC finish
ADC_CONTR &= ~0x10; //清除ADC结束标志
return (((u16)ADC_RES << 2) | (ADC_RESL & 3));
}
/***************** ADC键盘计算键码 *****************************
电路和软件算法设计: Coody
本ADC键盘方案在很多实际产品设计中, 验证了其稳定可靠, 即使按键使用导电膜,都很可靠.
16个键,理论上各个键对应的ADC值为 (1024 / 16) * k = 64 * k, k = 1 ~ 16, 特别的, k=16时,对应的ADC值是1023.
但是实际会有偏差,则判断时限制这个偏差, ADC_OFFSET为+-偏差, 则ADC值在 (64*k-ADC_OFFSET) 与 (64*k+ADC_OFFSET)之间为键有效.
间隔一定的时间,就采样一次ADC,比如10ms.
为了避免偶然的ADC值误判, 或者避免ADC在上升或下降时误判, 使用连续3次ADC值均在偏差范围内时, ADC值才认为有效.
以上算法, 能保证读键非常可靠.
**********************************************/
#define ADC_OFFSET 16
void CalculateAdcKey(u16 adc)
{
u8 i;
u16 j;
if(adc < (64-ADC_OFFSET))
{
ADC_KeyState = 0; //键状态归0
ADC_KeyHoldCnt = 0;
}
j = 64;
for(i=1; i<=16; i++)
{
if((adc >= (j - ADC_OFFSET)) && (adc <= (j + ADC_OFFSET))) break; //判断是否在偏差范围内
j += 64;
}
ADC_KeyState3 = ADC_KeyState2;
ADC_KeyState2 = ADC_KeyState1;
if(i > 16) ADC_KeyState1 = 0; //键无效
else //键有效
{
ADC_KeyState1 = i;
if((ADC_KeyState3 == ADC_KeyState2) && (ADC_KeyState2 == ADC_KeyState1) &&
(ADC_KeyState3 > 0) && (ADC_KeyState2 > 0) && (ADC_KeyState1 > 0))
{
if(ADC_KeyState == 0) //第一次检测到
{
KeyCode = i; //保存键码
ADC_KeyState = i; //保存键状态
ADC_KeyHoldCnt = 0;
}
if(ADC_KeyState == i) //连续检测到同一键按着
{
if(++ADC_KeyHoldCnt >= 100) //按下1秒后,以10次每秒的速度Repeat Key
{
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