This is schematic and Gerber files of PCB that is used for GPS tracking device with GSM link. Scheme has many valuable schematic features, like protected digital and analog I/Os, power part adapted for car power supply, etc.
Can be used as a reference design for anyone who wants to make own GPS GSM tracking system based on SIM508 module from Simcom.
A user-space device driver can do many of the things that kernel drivers can t, such as perform a long-running computation, block while waiting for an event, or read files from the file system. Unlike kernel drivers, a user-space device driver can use other device drivers--that is, access the network, talk to a serial port, get interactive input from the user, pop up GUI windows, or read from disks. User-space drivers implemented using FUSD can be much easier to debug it is impossible for them to crash the machine, are easily traceable using tools such as gdb, and can be killed and restarted without rebooting even if they become corrupted. FUSD drivers don t have to be in C--Perl, Python, or any other language that knows how to read from and write to a file descriptor can work with FUSD. User-space drivers can be swapped out, whereas kernel drivers lock physical memory.
The challenges associated with the design and implementation of Electro-
static Discharge (ESD) protection circuits become increasingly complex as
technology is scaled well into nano-metric regime. One must understand the
behavior of semiconductor devices under very high current densities, high
temperature transients in order to surmount the nano-meter ESD challenge.
As a consequence, the quest for suitable ESD solution in a given technology
must start from the device level. Traditional approaches of ESD design may
not be adequate as the ESD damages occur at successively lower voltages in
nano-metric dimensions.
The MAX3243E device consists of three line drivers, five line receivers, and a dual charge-pump circuit with±15-kV ESD (HBM and IEC61000-4-2, Air-Gap Discharge) and ±8-kV ESD (IEC61000-4-2, Contact Discharge)protection on serial-port connection pins. The device meets the requirements of TIA/EIA-232-F and provides theelectrical interface between an asynchronous communication controller and the serial-port connector. Thiscombination of drivers and receivers matches that needed for the typical serial port used in an IBM PC/AT, orcompatible. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-Vsupply. In addition, the device includes an always-active noninverting output (ROUT2B), which allowsapplications using the ring indicator to transmit data while the device is powered down. The device operates atdata signaling rates up to 250 kbit/s and a maximum of 30-V/ms driver output slew rate.
Internal Interrupts are used to respond to asynchronous requests from a certain part of themicrocontroller that needs to be serviced. Each peripheral in the TriCore as well as theBus Control Unit, the Debug Unit, the Peripheral Control Processor (PCP) and the CPUitself can generate an Interrupt Request.So what is an external Interrupt?An external Interrupt is something alike as the internal Interrupt. The difference is that anexternal Interrupt request is caused by an external event. Normally this would be a pulseon Port0 or Port1, but it can be even a signal from the input buffer of the SSC, indicatingthat a service is requested.The User’s Manual does not explain this aspect in detail so this ApNote will explain themost common form of an external Interrupt request. This ApNote will show that there is aneasy way to react on a pulse on Port0 or Port1 and to create with this impulse an InterruptService Request. Later in the second part of the document, you can find hints on how todebounce impulses to enable the use of a simple switch as the input device.Note: You will find additional information on how to setup the Interrupt System in theApNote “First steps through the TriCore Interrupt System” (AP3222xx)1. It would gobeyond the scope of this document to explain this here, but you will find selfexplanatoryexamples later on.
The PL2303 USB to Serial adapter is your smart and convenient accessory forconnecting RS-232 serial devices to your USB-equipped Windows host computer. Itprovides a bridge connection with a standard DB 9-pin male serial port connector inone end and a standard Type-A USB plug connector on the other end. You simplyattach the serial device onto the serial port of the cable and plug the USB connectorinto your PC USB port. It allows a simple and easy way of adding serial connectionsto your PC without having to go thru inserting a serial card and traditional portconfiguration.This USB to Serial adapter is ideal for connecting modems, cellular phones, PDAs,digital cameras, card readers and other serial devices to your computer. It providesserial connections up to 1Mbps of data transfer rate. And since USB does not requireany IRQ resource, more devices can be attached to the system without the previoushassles of device and resource conflicts.Finally, the PL-2303 USB to Serial adapter is a fully USB Specification compliantdevice and therefore supports advanced power management such as suspend andresume operations as well as remote wakeup. The PL-2303 USB Serial cable adapteris designed to work on all Windows operating systems.
We intend to develop a wifi enabled p2p file sharing system on a linux platform using jxta and java. The purpose is to build a system that can be ported to an embedded device at a later stage and be used for p2p file sharing using the 802.11b standard. 我們旨在Linux平臺上使用jxta 和java來開發一個支持wifi的p2p文件共享系統。其目的是建造一個以后可以移植到嵌入式設備的系統，使用802.11b標準進行p2p文件共享。 來源: http://sourceforge.net/projects/linux-p2p-wifi/
