SCM Network Introduction

Date：2009-04-09 Author：Shanghai ZLAN Views：7155

Abstract：this paper discusses the basic method of single chip computer (SCM) connected network (SCM online, single chip computer network), especially the method of 8-bit SCM networking. How does a single chip that has no OS support connect to the TCP/IP network? This paper proposes a single chip computer network effective method with embedded networking module, even Internet.

At present, the network technology of SCM is more and more important, especially the 51 MCU network communication is needed in many practical projects. As pervasive computing concept is more and more popular, the network connection advocated by pervasive computing of that all the smart devices connected to the Internet is becoming more clearer.

The single-chip microcomputer from low-end to high-end has the 8-bit microcomputer represented by 51 single-chip microcomputer and the 32-bit single-chip microcomputer represented by ARM. Different levels of SCM realize the network interface method is different. For high-end processors such as ARM, which can run embedded operating systems, such as embedded Linux, such MCU can be networked by using the TCP/IP stack that comes with the operating system. However, this approach is highly technical for both cost and developer.

But the scheme is relatively expensive compared with 51 MCU applications. Users may wish to implement 51 MCU network communication via TCP/IP source code, but porting an embedded TCP/IP protocol stack may require a lot of expertise. More important is the stability issue, product launch time problem.

The ZLSN series of serial port networking module of ZLAN can easily realize the network communication of MCU. It has various serial port interfaces, for example, one end of ZLSN3000 is the network port, and the other end is connected to the 5V power supply of two wires, and the two wires are directly connected to the RXD and TXD of the single chip. The solution is as follows (refer to the instructions of ZLSN2000):

1). Convenience: it is easy to make SCM network communication like SCM serial communication. What's more, the price is quite economical.

2). High stability: ZLSN2000 serial/Ethernet can be realized between full duplex, uninterrupted (such as 100 MB data uninterrupted send), high speed (115200 baud rate, for example) to send data, and does not lose in bytes.

3). You can do secondary development.

When the user selects the MCU network solution, it may be more concerned whether the secondary development can be carried out. If you can provide TCP/IP source code, then the user can directly call the socket functions like connect, send, receive, closet, listen, and develop the user's own program. The generic module solution does not provide these interfaces. The ZLSN module of ZLAN technology fully takes into account the user's requirements and provides the command interface of the module and the main SCM. The main SCM sends the socket command to the module via the serial port, for example, to connect the module to an address, that is, to send the “connect yourip: youport” to the module. This is equivalent to the user being able to call the socket function directly.