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rs-232 [2016/12/03 04:08] gongyu |
rs-232 [2021/02/06 16:27] (当前版本) gongyusu |
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| - | A serial interface is a simple way to connect an FPGA to a PC. We just need a transmitter and receiver module. | + | ## RS-232串行接口 |
| - | Async transmitter | + | An RS-232 interface has the following characteristics: |
| - | It creates a signal "TxD" by serializing the data to transmit. | + | * Uses a 9 pins connector "DB-9" (older PCs use 25 pins "DB-25"). |
| - | {{ :serialtxdmodule.gif |}} | + | * Allows bidirectional full-duplex communication (the PC can send and receive data at the same time). |
| + | * Can communicate at a maximum speed of roughly 10KBytes/s. | ||
| - | Async receiver | + | ### DB-9连接器 |
| - | It takes a signal "RxD" from outside the FPGA and "de-serializes" it for easy use inside the FPGA. | + | You probably already saw this connector on the back of your PC. |
| + | {{ :serialconnector.jpg |}} | ||
| - | {{ :serialrxdmodule.gif |}} | + | It has 9 pins, but the 3 important ones are: |
| - | This project has five parts | + | * pin 2: RxD (receive data). |
| + | * pin 3: TxD (transmit data). | ||
| + | * pin 5: GND (ground). | ||
| - | How the RS-232 serial interface works | + | Using just 3 wires, you can send and receive data. |
| - | * Baud generator | + | |
| - | * Transmitter | + | Data is commonly sent by chunks of 8 bits (we call that a byte) and is "serialized": the LSB (data bit 0) is sent first, then bit 1, ... and the MSB (bit 7) last. |
| - | * Receiver | + | |
| - | * Example of use | + | |
| + | ### 资源链接 | ||
| + | * 一个简短的[[http://penguin.dcs.bbk.ac.uk/academic/technology/physical-layer/asynchronous/|关于异步通信的页面]] | ||
| + | * 一个[[http://www.taltech.com/datacollection/articles/serial_intro|关于RS232串行通信的介绍]] | ||