The program language visual c + + is used to create the access function , which can be called by host program because the program language visual basic 6 . 0 can not be used to access the registers of the enhanced parallel port 用visualbasic6 . 0和visualc + +语言混合编程，成功的解决了用visualbasic6 . 0编写的主程序不能直接访问计算机并行接口的缺憾。
The new system consists of a single - chip computer system ( at89c51 + psd311 ) and alow power consumed analyzer by applying a new adc chip ads774 , and a dead - time correcting circuit is designed to correct the collecting time 本系统由单片微机系统( at89c51 + psd311 )组成多道缓存，由低功耗模数转换器组成分析器，与微型计算机通过打印并行接口实现数据通讯，并含有死时间校正电路。
All collected data is transmitted to portable computer through parallel port by epp protocol , so diesel working status can be test in field and diesel ' s fault can be diagnosed without disassembly 该仪器只有两种传感器，采用基于单片机的数据采集箱高速采集柴油机瞬时转速和油管压力信号，使用便携式电脑通过并行接口以epp协议进行数据采集控制和分析，以实现对柴油机工作状态的现场检测与不解体故障诊断。
The parallel interface used the self - made pci9052data acquisition card , using for the data acquisition in the upper position machine ; the serial interface used the rs232 standard interface , using for the movementcontrolled command transmission between the upper position machine and thelower position machine 并行接口采用自制的pci9052数据采集卡,用于上位机的数据采集;串行接口采用标准的rs232接口,用于上下位机之间运动控制命令的传输。
The most important project of the study on high speed solid - state storage technique with compactflash card array is the design of parallel interface unit , which consists of two pieces of isplsi 3448 , one piece of isplsi 3448 realizes 4 - route branching , totaling to realize 8 - route branching 并行接口单元设计包括两部分，一部分是cf卡读写的实现，另一部分是并行分路的实现，并行接口单元由两片isplsi3448组成，每片实现分四路，共分八路。
Comparing with the traditional parallel interface chips , they have fewer legs ~ smaller volume and use fewer resources . therefore , multiple channel data selecting controls keyboar & . display and alarm are realized through at89c52 ? four eight - bit i / o interface , without extending other i / o interface , making the system simplified and reliability increased 单片机的i / o接口芯片全部采用最新的串行工作方式接口芯片，与传统的并行接口芯片相比，它们引脚数少，体积小，占用的口资源少，因此用at89c52的4个8位的i / o口就完成了多个通道的数据采集、控制、键盘、显示和报警等功能，没有扩展其它i / o接口，使系统接线简化，可靠性提高。
We can take dsp to realize fast encryption algorithm because of its highly parallelism , application - specific hardware logic , and application - specific instructions . pci transaction and dsp processing of data can take place simultaneously for its dual - access ram ( daram ) and host port interface ( hpi ) . and , the time taken for interruption almost can be ignored because of deep buffer technology Dsp具有高度的并行结构、专用硬件逻辑以及许多专用指令，可以实现快速加密算法， dsp的双访问ram ( daram )和主机并行接口( hpi )可以实现数据pci传送和dsp处理同时进行，另外采用了深度缓冲技术，使花在主机中断上的时间几乎可以忽略不计，所以基于dsp的计算机数据加密卡pcijmc2000获得了较高的处理速度。
1284 - 1994 improves the rate of data transfer of parallel interface greatly and provides bi - directional data transfers it makes the demand for data is no more the bottleneck of peripheral performance at the same time , due to the characteristic of bi - directional data transfer , the host can identify the mode of peripheral sc the problem of mistake operation on unsupported device can be avoided Ieee1284 - 1994标准使并行接口的数据传输速度得到了极大的提高，并且支持双向数据传输。这使得对数据的需求量不再成为外设的性能瓶颈，同时由于双向数据传输特性，所以主机能识别外设的型号，这样就不至于对不支持的设备误操作。
8051 processor testing system was designed to test the sample in 16 bits parallel interface . because of the limitation of the testing system interface , however , easyarm2131 based on arm7tdmi - s was selected to use in 18 bits parallel interface test . and it sufficed the higher bits parallel interface test such as 18 bits , 24 bits , or more , while 8051 testing system ca n ' t do 为测试16bit并行接口,设计了以8051芯片为处理器的测试机;在测试18bit并行接口时,由于8051测试机的接口限制,采用了基于arm7tdmi - s核的easyarm2131开发板系统,解决了8051无法满足18bit乃至以后可能用到的24bit甚至更高的并行接口问题。
Working at automatic mode the system can transmit the data to computer through the parallel port which work at epp ( enhanced parallel port ) mode . then the computer shows the characteristic relation curves and acquires the characteristic arithmetic expression . the sampling frequency reach to 4khz , the core of control system is microcontroller uint ( mcu ) 89c51 ， the data acquisition is 12 bite 也可以工作在自动方式下通过并行接口（工作于epp模式） ，把测量到的数据输入计算机，在计算机上显示特性参数间的关系曲线，以及求出参数间的数学关系式，其采样频率可达4khz 。
