stc89c52引脚图及功能
时间: 2025-01-04 11:27:34 浏览: 27
### STC89C52 单片机引脚图及功能详解
#### 引脚概述
STC89C52是一款基于8051内核的增强型单片机,具有40个引脚。这些引脚可以分为电源引脚、复位引脚、振荡器引脚、I/O端口引脚和其他特殊功能引脚。
#### 电源引脚
- **VCC (Pin 40)**:正电源输入,通常接+5V直流电压[^1]。
- **GND (Pin 20)**:接地线,提供公共回路[^1]。
#### 复位引脚
- **RST/VPD (Pin 9)**:复位信号输入;当此引脚被拉高超过两个机器周期时,CPU会执行硬件复位操作并重新启动程序运行。此外,在低功耗模式下可用作外部供电检测输入端口。
#### 振荡器引脚
- **XTAL1 (Pin 19)** 和 **XTAL2 (Pin 18)**:这两个引脚用于连接石英晶体谐振器或陶瓷谐振器以及时钟源的选择开关。它们共同决定了系统的主频频率。
#### I/O端口引脚
STC89C52拥有四个双向可编程通用I/O端口P0~P3,每个端口都具备独立的数据方向控制能力:
- **Port 0 (P0.0-P0.7, Pin 39 to Pin 32)**:作为地址总线和数据总线使用时需外加上拉电阻;也可配置成普通的GPIO接口。
- **Port 1 (P1.0-P1.7, Pin 1 to Pin 8)**:纯粹的通用数字I/O端口,内部已集成上拉电阻。
- **Port 2 (P2.0-P2.7, Pin 21 to Pin 28)**:除了常规用途之外还可以扩展寻址空间至64KB外部RAM区域。
- **Port 3 (P3.0-P3.7, Pin 10 to Pin 17)**:多功能复用端口,集成了多种通信接口如UART(TXD/RXD),INT中断请求等额外特性。
#### 特殊功能引脚
- **ALE/PROG (Pin 30)**:地址锁存允许输出脉冲,可用于访问外部存储器时锁定低位地址信息;同时也支持在线编程期间触发写入命令。
- **EA/VPP (Pin 31)**:内外ROM选择控制,决定是否启用内置Flash Memory还是转向外部EPROM进行取指操作;另外在烧录固件过程中施加较高电压(+12V)实现芯片擦除功能。
```plaintext
+---+
40 | | 1
Vcc| | P1.0/T2
Rst | | P1.1/T2EX
XTAL2| | P1.2
XTAL1| | P1.3
Gnd | | P1.4
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