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疑难解答/FAQ

Q1	I am using Gateway for memory design. I noticed that Gateway has a very useful feature called Array paste, which can produce an array with specified numbers of rows and columns.

Q2	I used to work with multi-window schematic capture tools. How can I switch easily among several opened schematic sheets in Gateway which is single-window based?
Q3	有时候我在仿真的时候， 需要用到某些第三方的子电路， 也就是说只有该电路的网表（或者它的等效电路的网表）。请问在Gateway/Smartspice 环境下如何实现？

Q1	I am using Gateway for memory design. I noticed that Gateway has a very useful feature called Array paste, which can produce an array with specified numbers of rows and columns.
A1	Yes, Array Paste function on Gateway is a convenient feature for LCD, memory and other array structured circuits. Users may want to align instances from specified instance number, for example starting from X1~X100, X200~X300 etc. First, we place an initial instance. Take example of making an array consisting of X200~X300, we put an instance and name it as X199.
	Copy it and then Array paste, with some settings such as X Copies counts, Y copies counts, Offset distance in X or Y directions, Instance Name Order etc. After pressing OK, we can see an array starting from instance X200.
	For an array start from X1~X100, it is slightly tricky. Like what you have experienced, if you copy an initial instance X1, the array we get after Array paste is X2~X101. To deal with it, we do not Copy the initial instance; instead, we Cut the initial instance (it can be done by pressing Ctrl+x key) and followed by array paste. In such a way, we will get X1~X100 as we wish. We can see from the follow schematic, the pasted array started from instance X1.
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Q2	I am designing a circuit with an nWell CMOS process. I need to connect all those bulk terminals for all NMOS to ground node. However, my circuit is quite complex and if use wire to physically connect, will be very messy. Any suggestions?
A2	We can draw a wire from bulk terminal of any one NMOS, name it GND, and assign it to be a “Global connection”
	Copy this wire first, by Ctrl+C/Edit Menu/Right Mouse-click Menu, then press Shift key and hold, paste the wire to the location we want, by Ctrl+V/Edit Menu/Right Mouse-click Menu. Note, only when paste them, we need to press Shift. When we copy the wire, we do not need to do anything extra. We can see from picture below that the GND labeled wires are all connected together. For more information about the useful key “Shift”, please refer to Gateway User’s Manual, Section 2.3: Special Keys.
	However, once we use such a feature, Gateway will provide warning message saying: “A dangling wire has been detected” in the log window. We can disable it so that the warning message will not appear again, but it is not recommended because it may cause Gateway to miss the real dangling wires during the circuit check.
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Q3	有时候我在仿真的时候， 需要用到某些第三方的子电路， 也就是说只有该电路的网表（或者它的等效电路的网表）。请问在Gateway/Smartspice 环境下如何实现？
A3	我们可以创建一个新的子电路符号（symbol）， 设定好引脚的顺序和子电路名称， 然后在控制语句中把描述此子电路的网表文件引用进来，仿真就可以进行了。 举例说明一下：我们设计了一个电路， 打算用第三方的放大器来驱动一下。基于知识产权保护的考量， 设计公司的datasheet上通常只发布等效电路的网表。 以下就是一个例子，保存在 “EL5220_spice_model.spice”文件中 。 在Gateway 中， 去FileNewSymbol ， 进入新的symbol 编辑界面。 画出symbol 轮廓，加入引脚。 在本例的子电路中， 一共有5个引脚， 分别为 +input, -input, +Vsupply, -Vsupply 和 output。
	然后在symbol 编辑界面中， 从右键菜单或者GatewayEditProperties 中打开 Symbol Properties 窗口。 点击 Smartspice 进入 Smartspice String Editor 界面，输入： X@PATH %3 %2 %8 %4 %1 EL5220
	在这里需要注意的是symbol图中的、Smartspice string中的和网表文件中的引脚顺序要保持一致。 接下来在控制语句中加入： .include <路径>EL5220_spice_model.spice 至此， 仿真就可以继续了。
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