今天小编要和大家分享的是接口,总线,驱动相关信息，接下来我将从串口RS232引脚定义，存储器电路引脚及主要特性93lc46b/56b/66b 串口这几个方面来介绍。
接口,总线,驱动相关技术文章串口RS232引脚定义
1 逻辑电平
EIA-RS-232C 对电器特性、逻辑电平和各种信号线功能都作了规定。
在TxD和RxD上：
逻辑1(MARK)=-3V～-15V
逻辑0(SPACE)=+3～+15V
在RTS、CTS、DSR、DTR和DCD等控制线上：
信号有效（接通，ON状态，正电压）＝+3V～+15V
信号无效（断开，OFF状态，负电压)=-3V～-15V
2. 引脚定义
针脚 定义 符号
1 载波检测 DCD Pin 1 Received Line Signal Detector(Data Carrier Detect)
2 接收数据 RXD Pin 2 Received Data
3 发送数据 TXD Pin 3 Transmit Data
4 数据终端准备好 DTR Pin 4 Data Terminal Ready
5 信号地 SG Pin 5 Signal Ground
6 数据准备好 DSR Pin 6 Data Set Ready
7 请求发送 RTS Pin 7 Request To Send
8 清除发送 CTS Pin 8 Clear To Send
9 振铃提示 RI Pin 9 Ring Indicator
3. 9针和25针串口引脚对应关系
4 连线方法
Usually Not. While the normal PC hardware might well run with just Tx, Rx and Ground connected, most driver software will wait forever for one of the handshaking lines to go to the correct level. Depending on the signal state it might sometimes work, other times it might not. The reliable solution is to loop back the handshake lines if they are not used.
Handshake looping a PC serial connector |