14-07-2012, 03:15 PM
FPGA Implementation of RS232 to Universal serial bus converter
[attachment=27675]
1. INTRODUCTION
This paper describes the specification and implementation of converter from RS-232 to USB. This converter is responsible for receiving data from a pheripheral device’s serial interface and sending it to computer’s USB interface to the device. The problem faced with the old standards stimulated the development of a new communication protocol which should be easier to use, faster and more efficient. RS-232 is a definition for serial communication for 1:1 base. RS-323 defines the interface layer but not the application layer. To use RS-232 in specific situation, application specific software must be written on the devices on both ends of connecting RS-232 cable. RS-232 ports can either be accessed directly by an application or via a device driver in the operating system.
2. PROBLEM DESCRIPTION
The USB specification describes bus attributes, protocol definition, programming interface and other features required to design and build system and pheripheral compliant with USB standard.
The USB standard does not give this flexibility. When however an RS-232 port is used via an USB to RS-232 converter via USB works as a master\slave bus, where USB host as master and devices are the slaves. The only system resources required by an USB system are the memory location used by the USB system software and the memory and\or I\O address space and IRQ line used by the USB host controller. USB devices can be functional (displays, mice etc)or hubs used to connect other devices in the bus.
[attachment=27675]
1. INTRODUCTION
This paper describes the specification and implementation of converter from RS-232 to USB. This converter is responsible for receiving data from a pheripheral device’s serial interface and sending it to computer’s USB interface to the device. The problem faced with the old standards stimulated the development of a new communication protocol which should be easier to use, faster and more efficient. RS-232 is a definition for serial communication for 1:1 base. RS-323 defines the interface layer but not the application layer. To use RS-232 in specific situation, application specific software must be written on the devices on both ends of connecting RS-232 cable. RS-232 ports can either be accessed directly by an application or via a device driver in the operating system.
2. PROBLEM DESCRIPTION
The USB specification describes bus attributes, protocol definition, programming interface and other features required to design and build system and pheripheral compliant with USB standard.
The USB standard does not give this flexibility. When however an RS-232 port is used via an USB to RS-232 converter via USB works as a master\slave bus, where USB host as master and devices are the slaves. The only system resources required by an USB system are the memory location used by the USB system software and the memory and\or I\O address space and IRQ line used by the USB host controller. USB devices can be functional (displays, mice etc)or hubs used to connect other devices in the bus.