AT来自89C52单片机有哪些功能？

AT89C52就是个常用的8位单片机，低电压还高性能，用的是CMOS工艺。片子里有8KB的Flash程序存储器，能擦写上千次，还有256字节的RAM。这玩意是ATMEL家出的，技术靠谱，和标准的MCS-51指令集兼容，内部有个8位CPU加Flash存储，所以在电子圈里应用挺广的。
主要特点也简单：
1. 兼容MCS-51指令系统
2. 8KB可反复擦写Flash（能写1000次以上）
3. 32个双向I/O口
4. 内置256字节RAM
5. 3个16位定时/计数器，支持中断
6. 时钟频率支持0到24MHz
7. 2个串行中断，带可编程UART
8. 2个外部中断，总共支持8个中断源
9. 2条可编程读写控制线，支持3级加密
10. 支持低功耗空闲和掉电模式，能用软件睡觉和唤醒
11. 封装有PDIP、PQFP、TQFP、PLCC这些，方便各种板子用
引脚方面，AT89C52是标准的C51内核，封装常见的有PDIP，跟普通8xC52差不多。主要管脚包括：
- XTAL1（19脚）和XTAL2（18脚）接晶振，一般外接12MHz
- RST/Vpd（9脚）是复位脚，靠电阻电容电路复位
- VCC（40脚）接+5V，VSS（20脚）接地
- P0到P3是通用I/O口，功能靠代码定
比如在这个设计里：
- P0口（32~39脚）当N1控制口，连对应功能脚
- 13脚是IR接收输入
- 10脚和11脚是I2C总线，连N1的SDAS和SCLS
- 12、27、28脚做握手信号，跟主板CPU通信，用来检测制式和进入会聚调整状态
P0口是8位漏极开路双向口，可以当地址/数据复用总线。当输出时，每个口能驱动8个TTL门电路；写1时可作高阻输入。访问外部存储器时，它会分时做低8位地址和数据总线，这时候内部上拉电阻会启用。烧录Flash时，P0负责接收指令字节；校验时则输出字节，但得外加上拉电阻。
P1口……

比如用1ms宽高电平作为“0”，2ms宽高电平作为“1”，低电平全为1ms就可以用来做单线通信。

/*合泰单片机*/
#define DATA _pa6
unsigned char nub[5]={0x01,0x0b,0xfe,0xcd,0xee};
unsigned char Receive[10]={0x00};
unsigned char Receivetime;
unsigned char ReceiveBF=0x00;
unsigned char Receivecount=0x00;
unsigned char ReceiveC=0x00;
void __attribute((interrupt(0x10))) isr_time(void)//100us 定时器中断函数
{
_ptma0f=0;
switch(ReceiveBF)
{
case 0x00://引导码低
{
if(DATA)
{
if(Receivetime>85)
{
if(Receivetime<100)
{
ReceiveBF=0x01;
Receivetime=0x00;
}
else
{
ReceiveBF=0x00;
Receivetime=0x00;
}
}
else
{
ReceiveBF=0x00;
Receivetime=0x00;
}
}
else
{
Receivetime++;
}
break;
}
case 0x01://引导码高
{
if(DATA)
{
Receivetime++;
}
else
{
if(Receivetime>40)
{
if(Receivetime<55)
{
ReceiveBF=0x02;
Receivetime=0x00;
Receivecount=0x00;
ReceiveC=0x00;
}
else
{
ReceiveBF=0x00;
Receivetime=0x00;
}
}
else
{
ReceiveBF=0x00;
Receivetime=0x00;
}
}
break;
}
case 0x02://低电平
{
if(DATA)
{
if(Receivetime>10)//数据
{
if(Receivetime<25)
{
ReceiveBF=0x03;
Receivetime=0x00;
}
else
if(Receivetime<55)
{
ReceiveBF=0x04;
Receivetime=0x00;
}
}
}
else
{
Receivetime++;
}
break;
}
case 0x03://数据码
{
if(DATA)
{
Receivetime++;
}
else
{
if(Receivetime>25)//1
{
Receive[ReceiveC]=Receive[ReceiveC]<<1;
Receive[ReceiveC]=Receive[ReceiveC]|0x01;
Receivecount++;
if(Receivecount==8)
{
Receivecount=0x00;
ReceiveC++;
}
ReceiveBF=0x02;
Receivetime=0x00;
}
else//0
{
Receive[ReceiveC]=Receive[ReceiveC]<<1;
Receive[ReceiveC]=Receive[ReceiveC]&0xfe;
Receivecount++;
if(Receivecount==8)
{
Receivecount=0x00;
ReceiveC++;
}
ReceiveBF=0x02;
Receivetime=0x00;
}
}
break;
}
case 0x04://结束码
{
ReceiveBF=0x00;
Receivetime=0x00;
break;
}
}
}
void Send()
{
volatile unsigned char count=0x05;
volatile unsigned char datanub;
volatile unsigned char datacount;
//引导码
DATA=0;
dly100us(90);
DATA=1;
dly100us(45);
//数据码
while(count)
{
datanub=nub[5-count];
datacount=0x08;
while(datacount)
{
if(datanub&0x80)
{
DATA=0;
dly100us(15);
DATA=1;
dly100us(30);
}
else
{
DATA=0;
dly100us(15);
DATA=1;
dly100us(15);
}
datanub=datanub<<1;
datacount--;
}
count--;
}
//结束码
DATA=0;
dly100us(45);
DATA=1;
dly100us(45);
DATA=0;
dly100us(45);
DATA=1;
}