Overview of ZLAN Embedded Networking Solution

Date：2009-03-09 Author：Shanghai ZLAN Views：5417

The development of network and information technology makes the serial port devices managed by serial port, RS232 and RS485 no longer adapt to the pace of informatization. It is the inevitable trend that the transformation from serial port to network port, from serial communication of level class to Ethernet or Internet communication of networking class.

The network management of device has the following advantages over serial port:
1). The network mode is more flexible than the serial port. A serial connection is a physical connection, and networking is a logical link. Before every device needs to have a physical serial port line to connect with PC, if there have a lot of devices, the PC serial port is not enough to use, even for a serial port expansion is limited. But for the networking way, as long as the PC has a network wire access network, each device connect to the network, the connection can be realized.
2). The networking mode has the characteristics of distance and convenience. As long as the device access to network it can realize remote control, it can make full use of the convenience brought by the existing Internet. At present, the network has been extended to residential areas, offices, factories and so on, which can be connected to the network anywhere, saves the cost of wiring.
3). The networking mode can make use of existing network protocol, can use the Http protocol to access device, for example, use IPSec to encrypt the data, using the TCP protocol to ensure the accuracy of the data, which makes the performance of the device is greatly increased.
4). The device networking blocks the differences of various devices, and uses the socket standard interface to communicate, which facilitates the unified management of different types of devices.

Ethernet IEEE802.1 is currently used for most of the wired networking methods. Here are a few examples:

If the user does not want to redesign the original serial port, then you can use a serial device server, such as ZLAN series. The serial device server can transparently forward the original serial port data to the network. ZLAN serial device server support virtual serial port, it can virtually re-make the network connection to serial port, so that the user software no need modification, as upgrade from the original user solution of FIG 1 to ZLAN networking solution of FIG 2.

The user needs to modify the hardware design of the serial port device and integrate the Ethernet function into the PCB board. At this time, there are two kinds of situations:
1). User device is developed with high-end ARM system. At this time, the embedded operating system such as embedded Linux and WinCE can be transplanted directly on the ARM system, and the TCP/IP protocol stack has been integrated on this operating system. Therefore, users can communicate with PC by using socket programming on the device side.
2) The user device adopts the low-end 16-bit and 8-bit processor. It is difficult to implement TCP/IP on the user system. Because: a) The operation of the TCP/IP stack will take up a lot of CPU time, and the low-end processor will be difficult to handle, which will affect the operation of the user application. b) The operating system OS is not normally run on low-end processors, and it is difficult to schedule tasks between the user program and the TCP/IP stack. c) Stability is the most critical index of embedded TCP/IP protocol stack, and it is difficult for industrial application users to achieve the stability requirement of implementing TCP/IP stack.

At this time it can use ZLSN2000 of ZLAN as networking solution.

Shanghai ZLAN Information Technology Co., LTD., engaged in embedded networking technology development since 2003, attaches great importance to the investment of the core technology, has completed the core software such as ZLIP, ZLWeb, and won the state intellectual property office from the software copyright registration.

Advantage:

The advantage of ZLSN2000 embedded networking module solution is:

1). Stability: ZLSN2000 can achieve full duplex and continuous data transmission. It can be used in the high baud rate (for example, 115200), and data transform from serial port to Ethernet port and Ethernet port to serial port can be done at the same time without stop. A byte won’t be lost at this point. A lot of other similar products in this situation will lost packet, or even get off the network.
2). Moderate price: ZLSN2000 solution of ZLAN is also suitable for low-end system users. Because low-end system itself is low cost, if the cost of embedded network solution is too high, the system cost will be greatly increased. In fact, if the user develops an embedded networking solution, the price is close to even more than ZLSN2000 when considering the hardware cost + R&D input.
3). Super small volume: ZLSN2000 is only 4.3mm * 2.6mm.

The ZLSN2000 series module of ZLAN can quickly realize accessing to Internet, and the implementation steps are as follows:
1). Set aside a dual-row outlet of 10 pin+9 pin on the PCB board. To connect the ZLSN2000 module.
2). The 19-pins provide VCC (5V), GND, TXD and RXD. Serial ports TXD and RXD are connected with the serial port of user MCU.
3). The 19-pins lead to 4 pins to connect to the network wire.

The network parameters and serial port parameters of ZLSN2000 are set up through the Web or ZLVirCom program.

After that, MCU is sent to ZLSN2000 by serial port, and will be transparently sent to the computer specified by the destination IP. The data sent to ZLSN2000 by computer of destination IP will be transparently forwarded to MCU.