外文翻译

外文译文
出租车多功能计费器的设计理念
随着出租车行业的发展，对出租车计费器的要求也越来越高，用户不仅要求计费器性能稳定，计费准确，有防作弊功能；同时还要求其具有车票资料打印、IC卡付费、语言报话和电脑串行通信及税控功能。

不同国家和地址的计费方式存在差异，如有些地区有夜间收费及郊区收费等，而有些地区则无夜间收费和郊区收费；目前国内有些大城市要计计费器有税控功能，而有些城市无此要求；即使同一地区，不同车型的出租车其计费方式也有差别；而且出租车还面临几年一次的调价或调整计费方式等问题。

为此，我们设计了一款计费器。

该计费器内设置了多达64个选项系统上电、掉电以及供电电压降低时，第7脚产生复位输出，复位脉冲宽度的典型值为200ms，高电平有效，复位门限为4.65V。

计费器提供6个按键功能，但税控计费器不需要6个按键，只需要3个按键，因而无需4028译码器，利用CPU 的三条I/O线即可实现三个按键的功能。

1. 防作弊及脉冲输入模块。

为了提高计费器的防作弊功能，采用了两片PIC508，传感器中装一片PIC508，计费器中装一片PIC508。

其工作原理如下：每次计费器复位后，计费器中的PIC508送一随机数（1个字节）作为密码给传感器中的PIC508，车辆每产生一个脉冲，传感器中的PIC508均要将此密码送回到计费器的PIC508。

只有密码正确，计费器中的PCI508才发正确信息给CPU，表示输入了一脉冲，否则发错误信息给CPU。

当CPU收到三次错误信息（次数可任意设置）时，CPU报警表示有作弊现象。

由于不同时刻，即使同一个计费器的密码也不相同且是随机，因此采用该方法能效地防止司机作弊。

2 软件设计应注重的问题
由于计数器的选项多达64个，功能齐全，能适应不同地区的需要，软件编程及调试比较复杂，需要非凡小心。

为了使计费器稳定、可靠地工作，软件设计主要考虑了以下几个方面：
（1）为了防止计费器死机，软件编程时采用了指令冗余技术、软件陷阱技术以及软件看门狗技术。

（2）为了防止程序“乱飞”而非法修改计费器所设置好的各种参数，从软件的角度对计费器的各种参数进行了多重保护。

必须通过“合法”的途径才能修改参数，而程序“乱飞”也不能修改计费器所设置好的参数。

（3）司机卡、采集卡、收费卡、税控卡共用一个IC卡接口，税控模块优先访问插入的IC卡并进行判定，直接与税控初始化卡税务信息卡和税务稽查卡交换信息。

假如不是税控卡，则将控制权交给主控模块，主控模块要注重区分卡的类型，按照IC卡的有关控制命令正确编程。

（4）对DS1244Y时钟操作时，串行输入数据的第5字节的第5位（RST）须置0，以便DS1244Y能接收复位信号。

每次上电后，由软件对其复位。

（5）任何时候均要注重保存好计费器所处的状态及各种数据，复位后计费器能够回到原来的状态。

如计费器处于载客状态，复位后计费器仍然回到载客状态，且车资、收费里程、收费时间及单价同复位前一样。

（6）计费器与PC机串行通信时，PC机最好选用VB6.0语言。

VB6.0提供了串行通讯MSCOMM控件来为应用程序提供串行通信，其良好的用户界面、简单方便的串行通信和实用性强的优点，无须借用其它语言就可以开发出优秀的通信软件。

外文原文
Taxi multi-function devices design idea
Along with the development of the taxi trade to taxi devices, higher requirements, the user demand not only stable performance, toll-collection devices accurate, have anti-cheating function; Also ask its has ticket material printing, IC card payment, language BaoHao and computer serial communication and fiscal function. Different countries and address charging mode existing differences, such as some areas have night fees and charges, and some suburban district, no night charge fees and suburbs; At present domestic some big cities to plan a fiscal function, and the message accounting device in some cities without the requirement; Even though the same area, different models of taxi its billing way also has difference; And taxi also faces a weeklong years problems such as paid for or adjustment. Therefore, we design a new devices. This piece of up to 64 set within the electricity, off options system and power supply voltage electric low, the first seven feet produce reset output, reset the pulse width of the typical values for 200ms, high-level effective, reset
threshold for 465 V. The message accounting device provide 6 keys function, but tax-controlled devices don't need six key, need only three buttons, there is no need 4028 decoder, using CPU three I/O lines can realize three key functions.
1. Anti-cheating and pulse input module
. In order to improve the anti-cheating function, piece by PIC508 two pack a PIC508, sensors, PIC508 pack a piece. Its principle of work is as follows: after the message accounting device reset every time the PIC508 sent a piece, a random number (1 byte) as the password to the PIC508, vehicle sensor every produce a pulse, sensor PIC508 are in this password sent back to the
PIC508 piece. Only the correct password, devices PCI508 just send correct information to the CPU, says input a pulse, or hair false information to the CPU. When the CPU received three false information (set) can be arbitrary number, CPU alarm said cheating. Due to the different moments, even the same devices is not identical also and the password is random, so energy efficiency by using this method to prevent the driver cheating.
2 software design should pay attention to the problem
Because the options up to 64 counter, complete function, can meet the needs of different regions, software programming and
debugging is more complex, need special care. In order to make the message accounting device stability, working reliably, software design main consider the following aspects:
(1) in order to prevent the message accounting device crash, the software programming instruction redundancy technology, software trap technology and software watchdog technology. (2) in order to prevent program "flying" and illegal modify devices installed by good various parameters, from the Angle of the software for various parameters for the piece of multi-protection. Must pass "lawful" ways to modify the parameter, and program "flying" also can't modify devices installed by good parameters.
(3) driver card, acquisition card, ShouFeiKa, tax-controlled card common a IC card interface, tax-controlled module priority access to insert IC card and determination, direct and
tax-controlled initialization card tax XinXiKa and tax auditing card exchange information. If not be tax-controlled card, will control to the control module, should notice to distinguish control module card types, according to the relevant control commands IC card correctly programming.
(4) when DS1244Y clock operation of serial input data, the first five bytes of the first five (RST) must buy 0, so that DS1244Y can
receive reset signal. On each time after power of its reset by software.
(5) any time all should pay attention to preserve good devices in state and all kinds of data, reattachment to return to original state piece. If the message accounting device in passenger state, reattachment devices, and still back to passenger transport, charge state, charge time and price mileage with reset as before.
(6) the message accounting device and PC serial communication, the PC had better choose VB6.0 language. VB6.0 MSComm provides serial communication for the application controls to provide serial communication, its good user interface, simple serial communication and practical advantages, need not use other languages can develop good communication software.。