Welcome to the training module on RS232/422/485 to Ethernet Converter. This training module will discuss one solution for RS232/422/485 to Ethernet Converter.
The concept of serial communication is simple. The serial port sends and receives information bit by bit on a physical channel. Although it is slower than parallel communication, serial communication is widely used because parallel communication system would use too many wires and be very limited in overall distance. Serial communication methods to transfer data between equipment have been defined by standards for nearly half a century. The oldest and best known standard is RS232, a standard which defines the communication between DTE, data terminal equipment , and DCE, data communication equipment . The relatively short distances and low speed the RS232 serial interface can handle demanded for newer standards like RS422 and RS485. These standards define some features of electronic signal such as voltage level and signaling rate, as well as mechanical features.
In the Information-explosion era, many applications wants to transfer large amounts of data, such as audio and video streaming, so the old series standards, like RS-232 & RS-485 are not always the viable and fast solution of communication. This is especially true when using the microprocessor to collect data real time for transfer to another device for analysis. One way to improve the transfer speed is to use an Ethernet solution. Ethernet topology, which is based on bus and bus-star physical configurations, is currently the most frequently configured LAN network architecture. This also allows the data to be sent to multiple computers or devices both on a Local Area Network (LAN) or across the world. Despite the significant changes in Ethernet from a coaxial running at 10 Mbps to point-to-point links running at 1 Gbps and beyond, all generations of Ethernet share the same interface for higher layer in OSI network model. The Ethernet protocol offers advantages over the older serial communications in terms of its speed, reliability, and long distance.
Today, Ethernet is a well-defined standard for local and wide-area networks because of wide availability of reliable and cost effective products.. Countless devices access the Internet using TCP/IP over Ethernet. You are able to find it everywhere. Besides the commercial applications, like office network, Ethernet-based network are used in other areas, such as in industrial environment it provides real-time process monitoring and control. Here also lists other applications.
Thousands of industrial devices were developed based on the RS-232 interface. But for electronic communications, the evolutionary process was already kicking into a higher gear. Although the RS-232 / RS-485 serial port is quite ubiquitous, they do not solve all communication and connectivity problems. Most notably, RS-232 has distance limitations, and even RS-485 and RS-422 are limited by distance. In addition, either RS232 standard or RS422/485 standard, it only defines physical layer and data link layer so that the devices operating based on RS232/422/485 standard can’t access Ethernet. Therefore, a cost-effective way to operate in this new environment is the RS-232 / RS-485 serial-to-Ethernet converter, which brings legacy systems into a whole new panorama of networking applications. The purpose of the conversion is to change data format and protocol. In different applications, serial-to-Ethernet converter can support different Ethernet transmission mediums, such as twisted wire, coaxial cable and fiber. Since optical fiber has the advantages such as long transmission distance and low attenuation, the fiber featured with serial-to-Ethernet converter are an ideal solution for the long distance transmission. In practice, twisted wire has been widely used around the world, so the twisted wire assembled with a serial-to-Ethernet converter is a popular option.
This block diagram is our solution for serial-to-Ethernet converter. Serial to Ethernet converter is usually composed of RS232/422/485 transceiver, PHY transceiver and Network microcontroller. RS232/422/485 transceiver is used for the conversion of the voltage levels between RS232/422/485 standard and Transistor–Transistor Logic (TTL). PHY transceiver converts data stream to and from a MAC (Media Access Controller) and the physical media such as an optical fiber and twisted wire. Network microcontroller includes MAC layer, serial port and other peripherals interface. For the fiber-optic solutions, an optical transceiver is necessary to be involved to work with the converter. It receives and transmits optical signal and converts it into electronic signal. For the common twisted-wire solutions, a transformer is required to be added between the PHY transceiver and the RJ45 connector.
RS232/422/485 transceiver is used for the conversion of the voltage levels between RS232/422/485 standard signal and TTL (Transistor–Transistor Logic) signal. Via the transceiver, microcontroller can communicate with the devices like PC that features RS232/422/485 port. Here we introduce some parts from MAXIM, TI, and ADI. You may select the desired part based on the serial standard using in the device, and the requirement of supply voltage, no. of transmitter and receiver channels, and data rate.
Maxim’s MAX3160E multiprotocol transceivers allow you to use a single board layout to support RS-232 and RS-485 communication. The device offera a pin-selectable RS-232/RS-485 interface, which makes it easy to program each board to the desired protocol during production. The MAX3160E features enhanced electrostatic discharge (ESD) protection. All of the transmitter outputs and receiver inputs are protected to ±15kV using the Human Body Model. It incorporates a proprietary low-dropout transmitter output stage, and an on-board dual charge pump to allow RS-232- and RS-485-/RS-422-compliant performance from a +3V to +5.5V supply
The network controller is a microcontroller that integrates Ethernet MAC layer, serial ports and other peripherals interfaces. The explosive growth of Ethernet in the industrial networking and infotainment markets has created tremendous demand for high-performance MCUs with Ethernet peripherals. This table shows a list of microcontrollers that provides on-chip Ethernet.
The DS80C400 networked microcontroller includes an Ethernet interface with a full TCP/IP v4/6 network stack for simple connection to an Ethernet network. To enable access to the network, a full application-accessible TCP IPv4/6 network stack and OS are provided in ROM. The network stack supports up to 32 simultaneous TCP connections and can transfer up to 5Mbps through the Ethernet MAC. Its maximum system-clock frequency of 75MHz results in a minimum instruction cycle time of 54ns. Access to large program or data memory areas is simplified with a 24-bit addressing scheme that supports up to 16MB of contiguous memory. To accelerate data transfers between the microcontroller and memory, the DS80C400 provides four data pointers, each of which can be configured to automatically increment or decrement upon execution of certain data pointer-related instructions.
The LPC2364/66/68 series uses a high-performance 32-bit ARM7 core that operates at up to 72 MHz. Built for connectivity, these powerful yet cost-effective microcontrollers supports 10/100 Ethernet, full-speed (12 Mbps) USB 2.0, and CAN 2.0B. The Ethernet MAC has 16 KB of SRAM and an associated DMA controller on an independent AHB bus. The USB controller has 4 KB of USB SRAM and accessible DMA, and supports Control, Interrupt, Bulk, and Isochronous data-transfer modes with 32 endpoints. This architecture enables Ethernet and USB high-bandwidth peripherals to run simultaneously, without impacting the main application. Each device has up to 512 KB of on-chip Flash and up to 98 KB of on-chip SRAM memory. The multiple serial communications interfaces increase design flexibility, provide larger buffer size, and deliver higher processing power.
To accommodate the ever increasing demand for bandwidth, communication links have evolved from copper based channels running in the Mbps range to fiber optic based links running in excess of 10 Gbps. In our solution, the Fiber optic transceiver is used to receive and transmit optical signal, as well as convert the optical signal into electrical signal. Historically, single mode fiber based transceivers have been used to address applications requiring link distances of greater than a couple of hundred meters, while 850 nm based multimode devices addressed the short reach (<500m). We select some optical transceivers from Avago Technologies for your consideration.
The AFBR-5100Z family of transceivers from Avago Technologies provide the system designer with products to implement a range of FDDI and ATM (Asynchronous Transfer Mode) designs at the 100 Mbps/125 MBd rate. These transceivers for 2000 meter multimode fiber backbones are supplied in the small 1x9 duplex SC or ST package style for those designers who want to avoid the larger MIC/R (Media Interface Connector/Receptacle) defined in the FDDI PMD standard.
The PHY transceiver is a physical layer transceiver that converts data stream between MAC (Media Access Controller) layer and physical medium such as an optical fiber. PHY and MAC are connected by MII (Media Independent Interface). In this solution, the PHY should support fiber Ethernet standards.
In order to complete the solution, we also need other devices, like power adaptor, EEPROM, DE-9 connector, Fiber-Optic, Crystals, and LEDs. The power adaptor supplies power to the system, and usually utilizes a plug-in power adaptor to convert the AC mains power into DC power. POE technology can be used here to take the place of external power source. EEPROM can be used to store the customized program. The DE-9 9-pin connector is used for RS-232/422/485 connections. The crystal oscillator provides precise clock for the applications.
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RS232/422/485 to Ethernet Converter
RS232/422/485 to Ethernet Converter
Introduction <ul><li>Purpose </li></ul><ul><ul><li>To discuss one solution for RS232/422/485 to Ethernet Converter. </li></ul></ul><ul><li>Outline </li></ul><ul><ul><li>Serial communication basics </li></ul></ul><ul><ul><li>Ethernet basics </li></ul></ul><ul><ul><li>Serial-to-Ethernet converter basics </li></ul></ul><ul><ul><li>Our solution </li></ul></ul><ul><li>Content </li></ul><ul><ul><li>17 pages </li></ul></ul>
Serial Communication Protocol <ul><li>In serial communication, data is transmitted bitwise over a single wire. </li></ul><ul><li>Many popular serial communication standards exist </li></ul><ul><ul><li>RS-232 </li></ul></ul><ul><ul><li>RS-485 </li></ul></ul><ul><ul><li>RS-422 </li></ul></ul><ul><ul><li>SPI </li></ul></ul><ul><ul><li>I 2 C </li></ul></ul><ul><ul><li>… </li></ul></ul>Device 1 Device 2 0 0 0 0 0 0 0 0 0 1 1 1 1 1
Ethernet Protocol <ul><li>Ethernet is the most popular physical layer LAN technology in use today. </li></ul><ul><li>Ethernet is able to handle large amounts of data at high speed. </li></ul><ul><li>Ethernet still use wires to communicate. </li></ul><ul><ul><li>Over twisted-pair cables </li></ul></ul><ul><ul><li>Over optical fiber </li></ul></ul><ul><li>The Ethernet protocol offers advantages over the older serial communications in terms of </li></ul><ul><ul><li>High transmission speed </li></ul></ul><ul><ul><li>Reliability </li></ul></ul><ul><ul><li>Long distance </li></ul></ul>1000 Mbps Twisted-pair, Fiber Gigabit Ethernet 100 Mbps Twisted-pair, Fiber Fast Ethernet 10 Mbps Twisted-pair, Coaxial, Fiber Ethernet Speed Transmission Medium Protocol
Ethernet Applications <ul><li>Industrial Ethernet </li></ul><ul><li>Access Control Terminals, Time Recorders </li></ul><ul><li>Barcode Scanners, Magnetic Card Readers, RFID Readers </li></ul><ul><li>Security Devices </li></ul><ul><li>Power monitors, Power meters </li></ul><ul><li>Electronic Signboards for Retail Outlets </li></ul><ul><li>POS Systems, Vending Machines </li></ul><ul><li>PBX Stations etc </li></ul><ul><li>… </li></ul>
Serial to Ethernet Converter <ul><li>The limitations of the older serial protocols include: </li></ul><ul><ul><li>Distance limitation </li></ul></ul><ul><ul><li>Unable to access Ethernet </li></ul></ul><ul><li>Serial-Ethernet Converter is capable to link any serial (RS-232/422/485) devices to Ethernet network for access control or remote control and monitoring purposes. </li></ul><ul><li>Serial-to-Ethernet converter can support different Ethernet transmission mediums. </li></ul>Serial only Device 1 Serial to Ethernet Network Serial only Device 2 Serial to Ethernet
MAXIM DS80C400 MUC <ul><li>Single 8051 Instruction Cycle in 54ns </li></ul><ul><li>Flat 16MB Address Space </li></ul><ul><li>Multitiered Networking and I/O </li></ul><ul><ul><li>10/100 Ethernet Media Access Controller (MAC) </li></ul></ul><ul><ul><li>CAN 2.0B Controller </li></ul></ul><ul><ul><li>1-Wire Net Controller </li></ul></ul><ul><li>Robust ROM Firmware </li></ul><ul><li>Integrated Primary System Logic </li></ul>
NXP LPC2364/66/68 MUCs <ul><li>Based on 32-Bit ARM7TDMI-S™ core </li></ul><ul><li>Speeds up to 72MHz </li></ul><ul><li>Up to 512kB on-chip Flash and 58kB SRAM </li></ul><ul><li>Ethernet 10/100 MAC with DMA </li></ul><ul><li>USB 2.0 full-speed device with PHY and DMA </li></ul><ul><li>CAN 2.0B with two channels </li></ul><ul><li>General-purpose DMA controller </li></ul><ul><li>I 2 S, three I 2 C, three SPI/SSP, and four UARTs </li></ul><ul><li>4MHz internal RC (IRC) oscillator trimmed to 1% accuracy </li></ul>
Fiber Optic Transceiver LC Multimode -30 -15.7 1300 125 / 155 HFBR-5961ALZ Avago LC Multimode -31 -15.7 1300 125 / 155 HFBR-5963LZ Avago LC Multimode -30 -15.7 1300 125 / 155 HFBR-57E0LZ Avago MTRJ Multimode -34.5 -15.7 1300 125 AFBR-5903Z Avago ST Multimode -33.9 -20 1300 125 AFBR-5803ATZ Avago ST Multimode -34.5 -16 1300 125 AFBR-5103TZ Avago Connector Type Fibre Type Input Optical Power (dBm) Output Optical Power (dBm) Dominate Wavelength (nm) Date Rate (MBd) Part Number Manufacturer
AFBR-5103TZ 125 MBd MMF Transceiver <ul><li>Compliant with the Optical Performance Requirements of the FDDI PMD Standard </li></ul><ul><li>Compliant with the FDDI LCF-PMD Standard </li></ul><ul><li>Compliant with the Optical Performance Requirements of the ATM 100 Mbps Physical Layer </li></ul><ul><li>Compliant with the Optical Performance Requirements of 100 Base-FX Version of IEEE 802.3u </li></ul><ul><li>Multisourced 1x9 Package Style with choice of Duplex SC or Duplex ST Receptacle </li></ul><ul><li>Wave Solder and Aqueous Wash </li></ul>
PHY Transceiver 3.3V No 10/100Base-TX MII/RMII/SNI DP83848IVV National 3.3V 100Base-FX 10/100Base-TX MII/RMII/SNI DP83849IDVS/NOPB National 3.3V No 10/100Base-TX MII LAN83C185-JT SMSC 3.6V No 10/100Base-TX MII/RMII LAN8700IC-AEZG SMSC 2.5V, 3.3V 100Base-FX 10Base-T / 100Base-TX MII/RMII KSZ8721BL Micrel 3.3V No 10/100Base-T/TX MII/RMII/SMII KSZ8041TL Micrel 1.8V,3.3V 100Base-FX 10/100Base-TX MII/RMII/SMII KS8001L Micrel Voltage Fiber Support Application Interace Part Number Manufacturer
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