Serial port (RS - 232)

A serial port (RS - 232)

The serial interface is to FPGA Connect to PC A simple way to . We only need a transceiver module .
Asynchronous transmitter
It creates a signal by serializing the data to be transmitted “TxD”.

Asynchronous receiver
It is from FPGA External receiving signal “RxD”, And carry out “ Deserialization ”, In order to be in FPGA Easy to use inside .

RS-232 How the serial interface works ?

RS-232 The interface has the following characteristics :

• Use 9 Pin connector “DB-9”( old pc Use 25 Pin “DB-25”).
• Allow two-way full duplex communication (PC The computer can send and receive data at the same time ).
• It can be about 10KBytes/s The highest speed for communication .

DB - 9 The connector
You may have seen this connector on the back of your computer .

It has 9 One pin , but 3 The first important thing is :

• Pin 2: RxD( receive data ).
• Pin 3: TxD( To transmit data ).
• Pin 5:GND( The earth ).

Just use 3 line , You can send and receive data .
Data is usually generated by 8 Bit data block ( We call it byte ) Sent , And be “ serialize ”: First send LSB( Data bits 0), Then bits 1&#