Altium Designer is a rules-driven board design environment, in which you can define many types of design rules to ensure the integrity of your board. Typically, you set up the design rules at the start of the design process and then verify that the design complies with the rules as you work through the design, and at the end of the design process.
Earlier in the tutorial we examined the routing design rules and added a new width constraint rule. We also noted that there were already a number of rules that had been created by the PCB Board Wizard, and that there were some existing design rule violations against these default rules.
Altium Designer
PCB設(shè)計(jì)支持多級(jí)設(shè)計(jì)規(guī)則約束功能。用戶可以對(duì)同一個(gè)對(duì)象類設(shè)置多個(gè)規(guī)則,每條規(guī)則還可以限定約束對(duì)象的范圍。規(guī)則優(yōu)先級(jí)定義服從規(guī)則的先后次序。
為了校正電路板使之符合設(shè)計(jì)規(guī)則的要求,用戶可以利用設(shè)計(jì)規(guī)則檢查功能(DRC):
1.選擇 Design»Board Layers & Colors (快捷按鍵: L) 并確認(rèn)復(fù)選項(xiàng) Show 及 System Colors 區(qū)的DRC錯(cuò)誤標(biāo)記選項(xiàng)已被選取,這樣DRC錯(cuò)誤標(biāo)記將被顯示。
2.選擇 Tools»Design Rule Check (快捷按鍵: T, D),打開 Design Rule Checker 對(duì)話窗口,使能 online 和 batch DRC 選項(xiàng)。
規(guī)則檢測,Online和Batch均可以手工配置.
3.鼠標(biāo)點(diǎn)擊窗口左邊的 Report Options 圖標(biāo),保留缺省狀態(tài)下 Report Options 區(qū)域的所有選項(xiàng),并執(zhí)行 Run Design Rule Check 命令按鈕,隨之將出現(xiàn)設(shè)計(jì)規(guī)則檢測報(bào)告。并將同時(shí)彈出一個(gè)消息窗口。
4.點(diǎn)擊違例條款 Silkscreen over Component Pads ,用戶將跳轉(zhuǎn)到相應(yīng)違例報(bào)告區(qū)域。
5.點(diǎn)擊違例條款 Silkscreen over Component Pads 的任一條記錄,用戶將跳轉(zhuǎn)到PCB,并放大顯示出現(xiàn)違例的設(shè)計(jì)區(qū)域。注意,放大的倍數(shù)取決于在 System - Navigation 環(huán)境配置內(nèi)的設(shè)置。
顯示每項(xiàng)違例的細(xì)節(jié),本例的絲印與焊盤的間隔少于10mil.
6.顯示每項(xiàng)違例的細(xì)節(jié), 如上圖所示。注意用戶可以通過 View Configurations 窗口內(nèi)的 DRC Detail Markers 配置違例的圖形顯示顏色。
7.需要找出所有實(shí)際違反絲印與焊盤間安全間距規(guī)則約束的對(duì)象,可以選擇菜單 Reports»Measure Primitives 命令。注意,用戶可以通過快捷功能按鍵 CTRL+G 修改電氣柵格的值。如5mil。
8.To resolve this error we can either modify the footprint, increasing the separation, or we can edit the design rule, decreasing the required separation. For this tutorial we will edit the design rule, to do this select Design»Rules from the menus to open the PCB Rules and Constraints Editor dialog.
9.In the Manufacturing category, open the Silkscreen Over Component Pads rule type, and click on the existing rule.
10.Edit the Silkscreen Over Exposed Component Pads Clearance value, changing it from 10mil to 9mil.
These pads are closer than the 13mil specified in the Clearance Constraint design rule.
* 運(yùn)用習(xí)慣上與檢查晶體管上焊盤間的安全間距相同的技術(shù),檢查阻焊數(shù)據(jù)與焊盤之間的間隙。
Switch back to the PCB document and you will see that the transistor pads are highlighted in green, indicating a design rule violation.
1.Look through the errors list in the Messages panel. It lists any violations that occur in the PCB design. Notice that there are four violations listed under the Clearance Constraint rule. The details show that the pads of transistors Q1 and Q2 violate the 13mil clearance rule.
2.Double-click on an error in the Messages panel to jump to its location on the PCB.
Normally you would set up the clearance constraint rules before laying out your board, taking account of routing technologies and the physical properties of the devices. Let's analyze the error then review the current clearance design rules and decide how to resolve this situation.
3.Open the PCB Rules and Constraints Editor dialog (Design»Rules). Expand the Electrical, then the Clearance rule type. There will be one Clearance design rule, click on it to display its settings.
4.Note that this rule requires All objects to be away from All other objects, at least 13mil. Since the clearance between the transistor pads is less than this, they generate a violation when we run a DRC.
5.We know that the minimum distance between the transistor pads is just over 10mil, so let's set up a design rule that allows the clearance constraint of 10mil for the transistors only.
6.Select the Clearance type rule in the Design Rules folder on the left of the dialog, right-click on it, then select New Rule to add a new clearance constraint rule.
7.Click on the new Clearance rule, Clearance_1. Change the Name to Clearance_Transistors, and set the Minimum Clearance to 10mil in the Constraints section.
8.The final task is to set the Scope, or Full Query for the rule. There are a number of ways the rule could be scoped, the most appropriate in this case would be to target the rule to any component that uses the transistor footprint. To do that, select the Advanced (Query) option (in the upper section of the dialog), then click the *Query Builder button to open the Building Query from Board dialog.
9.Click Condition/Type Operator dropdown to Add first condition, and select Associated with Footprint from the list.
10.Set the Condition Value to BCY-W3/E4 (the footprint type being used by the transistor), then click OK to close the dialog. The new design rule should look like the figure shown below.
Design rule to set the clearance for all components using a specific footprint.
11.Click OK to close the PCB Rules and Constraint Editor dialog. The online DRC will run automatically, clearing the errors.
12.To confirm that the transistor pad clearance violations have been resolved, run the batch design rule check again (Tools»Design Rule Check). When the report opens scroll down and confirm that there are no violations.
一份清晰的DRC報(bào)告,顯示了所有被判定了的違反規(guī)則的設(shè)計(jì).
現(xiàn)在,用戶就完成了PCB版圖的設(shè)計(jì),然后可以開始產(chǎn)生輸出數(shù)據(jù)文檔。不過,在產(chǎn)生輸出制造數(shù)據(jù)之前,用戶還可以利用Altium Designer的三維視圖功能查看自己設(shè)計(jì)的PCB板。
在3D模式下查看電路板設(shè)計(jì)
現(xiàn)在,您的電路板設(shè)計(jì)已經(jīng)基本完成,是時(shí)候研究一下它的3D模式了。3D模式,可以讓您從任何角度觀察您設(shè)計(jì)的板。要在PCB編輯器中切換到3D,只需選擇View>>Switch To 3D [快捷鍵: 3]或者從列表中的PCB標(biāo)準(zhǔn)工具欄中選擇一個(gè)3D視圖配置。
Altium Designer軟件的3D環(huán)境的要求支持是DirectX及相關(guān)技術(shù),并使用一個(gè)兼容塊獨(dú)立的顯卡。對(duì)于如何測試您的系統(tǒng),以及讓Altium Designer可以使用DirectX,打開Preferences對(duì)話框中的PCB Editor - Display (Tools>>Preferences)。
圖30 3D旋轉(zhuǎn)展示圖
您可以滑動(dòng)變換大小來看,旋轉(zhuǎn),甚至在板中間看,只要您使用如下操作:
縮放——按Ctrl+鼠標(biāo)右拖,或者Ctrl+鼠標(biāo)滾輪,或者PAGE UP / PAGE DOWN鍵。
平移——鼠標(biāo)滾輪向上/向下,SHIFT+鼠標(biāo)滾輪向左/右或向右拖動(dòng)鼠標(biāo)來向任何方向移動(dòng)。
旋轉(zhuǎn)——按住SHIFT鍵進(jìn)入3D旋轉(zhuǎn)模式。光標(biāo)處以一個(gè)定向圓盤的方式來表示(圖11)。該模型的旋轉(zhuǎn)運(yùn)動(dòng)是基于圓心的,使用以下方式控制:
用鼠標(biāo)右拖曳圓盤Center Dot,任意方向旋轉(zhuǎn)視圖。
用鼠標(biāo)右拖曳圓盤Horizontal Arrow,關(guān)于Y軸旋轉(zhuǎn)視圖。
用鼠標(biāo)右拖曳圓盤Vertical Arrow,關(guān)于X軸旋轉(zhuǎn)視圖。
用鼠標(biāo)右拖曳圓盤Circle Segment,在Y-plane中旋轉(zhuǎn)視圖。
您可以使用View Configurations對(duì)話框[快捷鍵: L]來設(shè)定3D工作區(qū)的顯示選項(xiàng)??梢赃x擇各種表面和工作區(qū)的顏色以及垂直尺度,這樣可以得心應(yīng)手的來檢查PCB的內(nèi)部。一些表面有一種不透明的設(shè)置——越大的透明度的值越大,越少表示的光通過表面的光強(qiáng)度越小,使物體背面后面不明顯。您也可以選擇顯示3D物體本身或者以2D層的顏色來著色該3D對(duì)象。
您可以將3D STEP格式模型導(dǎo)入到元器件的封裝和PCB設(shè)計(jì)中并創(chuàng)建自己的3D物體。您也可以以STEP和DWG / DXF格式來輸出PCB文件,以便運(yùn)用到用于其他程序中。3D Vviewer可以導(dǎo)入VRML 1.0/IGES/STEP格式的3D物件,也可以導(dǎo)出IGES和STEP格式的3D物件。
注:任何時(shí)候在3D模式下,您可以以各種分辨率創(chuàng)建實(shí)時(shí)"快照(snapshots)",使用CTRL + C復(fù)制,這樣就可以將圖像(Bitmap格式)存儲(chǔ)在Windows剪貼板中,用于其他應(yīng)用程序。
為元器件封裝創(chuàng)建和導(dǎo)入3D實(shí)體
到目前為止,我們已經(jīng)到了最終PCB數(shù)據(jù)的核實(shí)查和輸出階段。Altium Designer軟件的3D環(huán)境提供了一個(gè)逼真的優(yōu)良的供視圖查看及檢查PCB組裝的環(huán)境條件,是一個(gè)逼真的環(huán)境。
元器件封裝本身存儲(chǔ)有3D模型,用于在3D環(huán)境下渲染該元件。此外,精確的元器件間隙檢查、甚至是裝配整個(gè)PCB和外部的自由浮動(dòng)的3D機(jī)械物體外殼都是可能的。這將用到機(jī)械CAD軟件包,創(chuàng)建一個(gè)設(shè)計(jì)一體化的新的水平,這些Altium Designer軟件正好可以提供。
如需要為元器件創(chuàng)建3D實(shí)體的詳細(xì)資訊,請(qǐng)查找Creating Library Components教程中的3D元器件詳細(xì)部分。
如需用MCAD軟件進(jìn)行3D實(shí)體一體化設(shè)計(jì)的更多信息,請(qǐng)查找 Integrating MCAD Objects and PCB Designs教程。
在 Integrating MCAD Objects and PCB Designs教程中,我們?cè)O(shè)計(jì)的板已經(jīng)通過器件的3D模型完成了(圖31)。教程將用機(jī)械外殼來裝起整塊板(圖32)。板和元器件可以在Altium Designer軟件安裝中的 Examples/Tutorials/multivibrator_step文件夾中找到。
圖31 3D效果圖
圖32 .裝配效果圖
檢驗(yàn)PCB板設(shè)計(jì)
Altium Designer提供了一個(gè)規(guī)則驅(qū)動(dòng)設(shè)計(jì)環(huán)境,在這里能夠設(shè)計(jì)PCB,并且允許我們定義很多類型的設(shè)計(jì)規(guī)則來保證我們的PCB設(shè)計(jì)的完整性。典型地,我們?cè)谠O(shè)計(jì)過程開始時(shí)建立設(shè)計(jì)規(guī)則,再在設(shè)計(jì)過程結(jié)束后用這些規(guī)則來校驗(yàn)修正設(shè)計(jì)標(biāo)準(zhǔn)。
在較早的教程指南中,我們檢查了布線設(shè)計(jì)的規(guī)則和增添了一個(gè)新的寬度約束規(guī)則。我們還注意到,已經(jīng)有一些由PCB Board EizardWizard創(chuàng)建的規(guī)則。
為了核實(shí)已經(jīng)布好的電路板遵守設(shè)計(jì)規(guī)則,我們來執(zhí)行設(shè)計(jì)規(guī)則檢查(DRC):
1.選擇Design>>Board Layers & Colors(快捷鍵:L),保證在System Colors部分中的DRC Error Markers選項(xiàng)中的Show按鈕已經(jīng)使能(打鉤),以保證顯示DRC錯(cuò)誤標(biāo)記。
2.選擇Tools - Design Rule Check(快捷鍵:T,D)。保證在Design Rule Checker對(duì)話框的實(shí)時(shí)和批處理設(shè)計(jì)規(guī)則檢測都被配置好。在其中一個(gè)各類上單擊,比如:Electrical,可以看到屬于那個(gè)種類的所有規(guī)則。
3.保持所有選項(xiàng)為默認(rèn)值,點(diǎn)擊Run Design Rule Check按鈕。DRC就開始運(yùn)行,報(bào)告文件Multivibrator.DRC就打開了。錯(cuò)誤結(jié)果也會(huì)顯示在信息面板。點(diǎn)擊進(jìn)入PCB文件,我們將會(huì)看到,該晶體管的焊盤是以綠色突出顯示的,顯示違反設(shè)計(jì)規(guī)則。
4.通過在信息面板中看錯(cuò)誤報(bào)告清單,它列出發(fā)生在PCB設(shè)計(jì)的任何違反規(guī)則行為。注意有四種列出在清除約束規(guī)則中的違反規(guī)則。細(xì)節(jié)表明,晶體管Q1和Q2違反13mil的最小安全距離規(guī)則。
圖33保持所有選項(xiàng)為默認(rèn)值
1.雙擊Messages面板中的錯(cuò)誤,可以跳到對(duì)應(yīng)的PCB中的位置。
通常,我們會(huì)在布線之前,設(shè)置我們的安全距離規(guī)則,同時(shí)考慮到布線技術(shù)和設(shè)備的物理性能。讓我們分析錯(cuò)誤,然后再次檢查現(xiàn)行的安全距離設(shè)計(jì)規(guī)則和決定如何解決這種情況。
圖34錯(cuò)誤信息
為了找出兩個(gè)晶體管焊盤間的真實(shí)最小安全距離,有以下步驟:
1.選中PCB文件,光標(biāo)定位于一個(gè)晶體管,按下PAGE UP鍵來放大視圖影像。
2.選擇Reports - Measure Primitives(快捷鍵:R,P)。光標(biāo)將變成十字形字準(zhǔn)線。
3.使光標(biāo)定位于晶體管左邊的焊盤中間,并點(diǎn)擊或按下ENTER 。因?yàn)楣鈽?biāo)是超過兩焊盤和連接它的布線,一個(gè)菜單會(huì)彈出讓用戶選擇所需的對(duì)象。從彈出式菜單中選擇晶體管的焊盤。
4.再一次,使光標(biāo)定位于晶體管中間,并點(diǎn)擊或按下ENTER 。從彈出式菜單中選擇晶體管的焊盤。一個(gè)顯示最小距離的信息框打開了,顯示兩個(gè)焊盤邊緣的最小距離是10.63mil 。
5.關(guān)閉信息對(duì)話框,右鍵單擊或按下ESC退出測量模式,然后使用V 、F的快捷鍵,重新縮放文件。
讓我們看看當(dāng)前的安全距離設(shè)計(jì)規(guī)則:
1.從菜單中選擇Design - Rules (快捷鍵:D,R)來打開PCB Rules and Constraints Editor對(duì)話框。雙擊Electrical種類,在右邊的對(duì)話框顯示所有的電氣規(guī)則。雙擊該安全距離類型,然后按一下就安全距離規(guī)則點(diǎn)擊"Clearance"規(guī)則一項(xiàng)來以打開它。該對(duì)話框底部的區(qū)域?qū)粋€(gè)單一的規(guī)則,標(biāo)明整個(gè)PCB板的最小安全距離為13mil 。晶體管之間的焊盤的距離小于安全距離,這就是為什么當(dāng)我們運(yùn)行DRC的時(shí)候,它們出現(xiàn)了違反規(guī)則的信息。
我們現(xiàn)在知道兩個(gè)晶體管之間的最小焊盤距離是10mil多一點(diǎn),讓我們建立了一個(gè)只為晶體管的設(shè)計(jì)規(guī)則,大小為10 mil。
1.在設(shè)計(jì)規(guī)則文件夾中,選擇安全間隙類型,點(diǎn)擊右鍵并選擇新規(guī)則添加一個(gè)新的安全間隙約束規(guī)則。
2.點(diǎn)擊新的安全間隙規(guī)則,Clearance_1。在resulting頁面中的Constraints章節(jié)中,設(shè)置Minimum Clearance為10 mil。
3.點(diǎn)擊Advanced (Query),再點(diǎn)擊Query Helper從Memberships Checks去建立條件檢索,或者也可以為第一個(gè)對(duì)象(圖35)在接下來的條件檢索中打印進(jìn)去。
HasFootprintPad('TO-92A','*')
那個(gè)星號(hào)表明在封裝里名為"TO-92A"的任何焊盤。
1.保持第二個(gè)對(duì)象范圍為ALL,并單擊OK。單擊Apply,然后點(diǎn)擊OK以關(guān)閉PCB Rules and Constraints Editor對(duì)話框。
2.現(xiàn)在,我們可以從設(shè)計(jì)規(guī)則檢測對(duì)話框(Tools - Design Rule Check)按一下運(yùn)行設(shè)計(jì)規(guī)則檢查按鈕。重新運(yùn)行DRC,不會(huì)有違反規(guī)則的行為。
3.保存已經(jīng)完成的PCB和工程文件。
圖35 使用PCB規(guī)則系統(tǒng)規(guī)定參數(shù)編輯器對(duì)話框創(chuàng)建規(guī)則。
恭喜,用戶已經(jīng)完成了PCB的布局布線,準(zhǔn)備生成輸出文件。
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