动态手机网站,wordpress category 自定义,北京网站搭建开发,深圳专业网站建设公司排名类型#xff1a;行业软件大小#xff1a;1.1M语言#xff1a;中文 评分#xff1a;6.5标签#xff1a;立即下载这篇文章是我的个人实践经验#xff1a;很多朋友在做Proteus硬件仿真的时候可能都碰上了仿真速度慢的问题#xff0c;在点击了开始仿真之后#xff0c;CPU过…类型行业软件大小1.1M语言中文 评分6.5标签立即下载这篇文章是我的个人实践经验很多朋友在做Proteus硬件仿真的时候可能都碰上了仿真速度慢的问题在点击了开始仿真之后CPU过载速度极慢无法正常进行仿真Proteus在信息栏提示CPU被使用情况可能高达90%到100%并没有按照真实速度仿真点击信息栏中的提示信息就弹出一个对话框说是 Simulation is not running in real time due to excessive CPUload,鼠标点击提示会展开一个消息框下面就是消息框内的内容This message has been generated because the simulation has been unable to keep up with real time for more than 20 consecutive simulation frames. This does not affect the accuracy of the simulation in any way, but it will mean that the simulated system may respond much more slowly to interactive events(e.g. push buttons).See Also:How to make simulations run faster这里的说明中可以看到至少两个信息第一速度慢并不影响仿真精度第二我们可以点击最下方那句话打开另一个链接来加速仿真那么我们就继续按照提示来寻找答案。(也许我们的Proteus版本不同这些链接打开顺序和方法可能不一样我是用的是7.1的版本)点击 How to make simulations run faster打开Proteus的帮助进入一个英文界面我把原文全部贴在这里之后和你一起解读。ADVANCED TOPICSHOW TO MAKE INTERACTIVE SIMULATIONS RUN FASTERIntroductionAlthough Proteus VSM is able to run many interactive simulations in realtime, it should be fairly obvious that this cannot be the case for allcircuits. For example, it is perfectly possible to draw a circuit that willoscillate at 1GHz, but there is no way that this can be simulated in realtime on a computer that may not even execute one machine instruction in 1ns.In this section, we will explain in a little more detail what determines thecomplexity of a simulation and how you can optimize a circuit to maximize thesimulation speed.Using Digital Resistor and Diode ModelsFirst and foremost in this context, it is vital to understand the differencebetween analogue and digital simulation within ProSPICE. This is because thesimulation of digital circuitry is two or three orders of magnitude (i.e. upto 1000 times) faster than the simulation of analogue circuitry. It is forthis reason that ProSPICE contains a digital simulator at all - that byrepresenting the operation of digital components as an event driven process,a great deal of unnecessary computation can be avoided.For example, whilst a PC with 600MHz P3 processor can simulate around 2million digital events per second, the same computer will only be able tosimulate a sine wave generator running up to about 2kHz before the CPU loadreaches 100%. Such a waveform will require about 60,000 analogue timepointsto be computed per second, and each timepoint will require a convergentsolution of the circuit nodal equations to be established - a process vastlymore complex than processing a simple digital event.For many components, it should be fairly intuitive as to whether analogue ordigital simulation will be required. For example, nearly all TTL and CMOSparts are represented by digital models, whereas analogue ICs such as op-amps, comparators and so forth are represented by analogue models. Allcomponents which are represented by standard SPICE models require analoguesimulation.However, a grey area arises for components which - though strictly analoguein nature - can be represented by a digital model for some purposes. Inparticular, diodes - and perhaps more surprisingly - resistors fall into thiscategory. This becomes highly relevant in the context of wire-or logic, pull-up resistors, devices with open-collector outputs, and in diode-resistorlogic networks.Example 1 - Wire-Or LogicThe following circuit section shows a typical wire-or logic network:U1:A and U1:B have open-collector outputs and can only sink current. A logic1 output level results in a high impedance condition. In terms of DSIM, thismeans that the gate outputs drive either an SLO (strong low) or a FLT(floating) logic state. Now if resistor R1 is modelled in the analoguedomain, PROSPICE must insert a digital to analogue interface object betweenthe logic gates and the resistor, and then an analogue to digital interfaceobject between the resistor and the input to U2:A. This will result inwonderfully detailed simulation of the rise-fall waveforms at this node, andthe current flow through R1, but will also result in a great deal ofcomputation every time the output of U1:A or U1:B changes state.All this can be avoided if R1 is modelled digitally. In this case, itsbehaviour is to convert the SHI logic state of VCC to a WHI (weak high) logiclevel. When either NAND gate pulls low, the SLO state overrides the WHI statefrom the resistor and the net state is resolved to be logic low. But whenneither gate sinks current, the WHI state beats the FLT state and the netrises to logic high. All this can be managed within the digital simulationparadigm and no analogue simulation is required.Therefore, pull up resistors of any kind should almost always be modelleddigitally.Example 2 - Diode-Resistor LogicAnother case where seemingly analogue circuitry can be modelled in thedigital domain is diode-resistor networks of the sort shown below. These areoften found around keypad scanning circuitry where the diodes serve toprevent short circuits between the row driving lines if more than more thanone key is depressed simultaneously.As with the wire-or logic example, ProSPICE will quite happily model this inthe analogue domain but it will be computationally expensive. If a digitalresistor model is used as above, and a diode is seen as a device which willpass only low logic level from cathode to anode and only a high logic levelfrom anode to cathode, then the whole network can once again be modelleddigitally.Since keypad scanning routines tend to operate at some speed, and there areoften numerous diodes and resistors, this is a very important optimization tobe aware of.How to Select the Digital Resistor Model1. Point at the resistor you wish to change and press CTRL-E.2. Click the Edit All Properties as Text checkbox.3. Change the PRIMITIVE property to readPRIMITIVEDIGITAL,RESISTORIf you are building a circuit from scratch, and know that you will want aparticular resistor to be modelled digitally, you can also achieve this bypicking the PULLUP or PULLDOWN models from the component library. Thisdevices already contains the PRIMITIVE property as above.How to Select the Digital Diode Model1. Point at the diode you wish to change and press CTRL-E.2. Click the Edit All Properties as Text checkbox.3. Change the PRIMITIVE property to readPRIMITIVEDIGITAL,DIODE4. Delete any MODEL property, as SPICE parameters have no meaning for thedigital diode model.If you are building a circuit from scratch, and know that you will want aparticular diode to be modelled digitally, you can also achieve this bypicking the DIODE-DIGITAL device the component library. This device alreadycontains the PRIMITIVE property as above.Optimizing Memory Accesses to External RAM and ROMMany larger microprocessor designs make use of ROM, RAM or EEPROM memorydevices external to the microcontroller itself. These may store the programcode, or be used to supplement internal SRAM present within the CPU chipitself. Given a correct address decoding circuit, and assuming that thememory device is modelled, Proteus VSM will correctly simulate such designsas drawn. When the CPU accesses external memory, the model will drive theaddress, data and control lines appropriately, and external decode logic andmemory model will respond by reading or writing the appropriate locations.This is quite useful if you wish to verify that your memory decodingcircuitry works as designed, but is also extremely expensive in terms ofcomputation. Setting up a 16 bit address will create a minimum of 16 digitalevents and reading or writing a byte of data to/from data bus will generateanother 8. Removing the data from the bus afterwards will create another 8events. Where address and data lines are multiplexed, as in the above HC11design, even more events will be generated. All this compares veryunfavourably with the ability of a VSM CPU model to execute an instructionusing just one event per machine cycle.Therefore, we have provided the CPU models with the ability to simulateaccesses to external memory internally to the model. At the time of writingthis applies to the 8051,HC11 and the larger AVR CPU models. External memory may be declared usingEXTRAM, or EXTROM properties which specify the memory range for each block ofexternal memory. Full details are provided in the model specific help forthese processors, which you can access from the Edit Component dialogue form,or from the Start Menu.Once the external memory map has been defined in this way, instructions whichaccess external memory within the specified ranges can be simulated withoutgenerating large numbers of digital events. Accesses to memory mappedperipherals can still be fully simulated, since these will lie at locationsoutside the memory ranges specified in the EXTRAM and EXTROM properties.这里就列出了所有问题的根源了各位朋友不妨多看看这里的英文帮助磨刀不误砍柴工这里的帮助内容比任何人的经验之谈要高明得多好了让我来读读这里的帮助下面是我读出的基本内容之一第一使用数字式的电阻和二极管(Using Digital Resistor and Diode Models)这句话是我的翻译原文的意思是如果把所有的二极管和电阻都看成是模拟量那样仿真的话Proteus的速度会大大下降所以所有的上拉电阻都可以看成是数字量的模拟(原文是Therefore, pull up resistors of any kind should almost always bemodelled digitally.)而一些作为逻辑门电路用的二极管也可以看成数字式的因此需要对仿真的元件进行设置。1)对电阻的设置(How to Select the Digital Resistor Model) How to Select the Digital Resistor Model1. Point at the resistor you wish to change and press CTRL-E.2. Click the Edit All Properties as Text checkbox.3. Change the PRIMITIVE property to readPRIMITIVEDIGITAL,RESISTOR2)对二极管的设置(How to Select the Digital Diode Model)1. Point at the diode you wish to change and press CTRL-E.2. Click the Edit All Properties as Text checkbox.3. Change the PRIMITIVE property to readPRIMITIVEDIGITAL,DIODE4. Delete any MODEL property, as SPICE parameters have no meaning for thedigital diode model另外说明在编辑Properties时在文本框里键入的内容若用中括号{}括起来那么在仿真界面就不会显示出来比如{MODFILE74AND2.MDF}{PACKAGEDIL14}{ITFMODTTL}第二:Optimizing Memory Accesses to External RAM and ROM这个问题我还没有遇到过也不太明白其中的内容希望比较熟悉单片机方面有的朋友做补充了
