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The difference between USB to serial port and USB protocol
Date:2018-08-31 17:28:49   Browse:0

Regarding the common question about SV613 RF module:  Does SV613 module can be used as USB protocol module ?


In the normal data transmission system(as shown photo1), the Port for data transfer has the fixed format requirement, Firstly,the input data will come from USB port, and then enter into MCU via level translator, Note that that data is still serial protocol data, non-serial protocol data cannot be recognized and processed by SV613 Module


一. USB to serial port

The two parties which communicate via USB to serial port shall comply with the serial communication protocol, the serial port sends and receives data by bit, includes Start bit, data bit, parity check bit, stop bit; the bit rate shall be set before communication. On the specific hardware,it has different standards,such as TTL,RS232,RS485,different standards logic with different electrical level. 

 

 

 USB protocol

    In a practical application,the two parties which communicate via USB Interface shall comply with the USB protocol,the Standard USB cable adopts four core cable: 5V power line (Vbus),differential data line negative (D-), differential data line positive (D+), and ground (GND). USB is a communication protocol that supports serial data transmission between a USB host and a USB device.

The host acts as the calling party,it adopts two signaling modes: full-speed mode 12Mb/s and low-speed mode 1.5Mb/s. USB uses four data transmission methods: control transmission, interrupt transmission, bulk transmission, and isochronous transmission.

The USB system consists of three logical layers: the function layer, the USB Device layer,and the USB bus interface layer. And each layer is composed of the host and the different functional modules of USB device, as shown in the following figure:

 

The SV613 that using USB to serial port is incompatible with the device using the USB interface on the hardware circuit, and the SV613 modules can only communicate via serial port and cannot send USB protocol data.

 


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