/* -*- tab-width: 4 -*-
*
* Electric(tm) VLSI Design System
*
* File: Nand2en_sy.java
*
* Copyright (c) 2003 Sun Microsystems and Static Free Software
*
* Electric(tm) is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Electric(tm) is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Electric(tm); see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, Mass 02111-1307, USA.
*/
package com.sun.electric.tool.generator.layout.gates;
import com.sun.electric.database.hierarchy.Cell;
import com.sun.electric.database.prototype.PortCharacteristic;
import com.sun.electric.tool.generator.layout.FoldedMos;
import com.sun.electric.tool.generator.layout.FoldedNmos;
import com.sun.electric.tool.generator.layout.FoldedPmos;
import com.sun.electric.tool.generator.layout.FoldsAndWidth;
import com.sun.electric.tool.generator.layout.LayoutLib;
import com.sun.electric.tool.generator.layout.StdCellParams;
import com.sun.electric.tool.generator.layout.TechType;
import com.sun.electric.tool.generator.layout.TrackRouter;
import com.sun.electric.tool.generator.layout.TrackRouterH;
import com.sun.electric.tool.Job;
public class Nand2en_sy {
private static final double nmosTop = -9.0;
private static final double pmosBot = 9.0;
private static final double wellOverhangDiff = 6;
private static final double inaY = -4.0;
private static final double inbY = 4.0;
private static final double outHiY = 11.0;
private static final double outLoY = -11.0;
private static void error(boolean pred, String msg) {
Job.error(pred, msg);
}
public static Cell makePart(double sz, StdCellParams stdCell) {
TechType tech = stdCell.getTechType();
sz = stdCell.roundSize(sz);
String nm = "nand2en_sy";
sz = stdCell.checkMinStrength(sz, 1, nm);
// compute number of folds and width for full strength PMOS
double spaceAvail = stdCell.getCellTop() - wellOverhangDiff - pmosBot;
double lamPerSz = 6;
double totWid = sz * lamPerSz;
FoldsAndWidth fwP = stdCell.calcFoldsAndWidth(spaceAvail, totWid, 1);
error(fwP==null, "can't make "+nm+" this small: "+sz);
// Compute number of folds and width for weak PMOS.
// Don't let transistor size drop below 5 lambda.
totWid =
Math.max(3, sz * lamPerSz * stdCell.getEnableGateStrengthRatio());
FoldsAndWidth fwW = stdCell.calcFoldsAndWidth(spaceAvail, totWid, 1);
// Compute number of folds and width for NMOS
int nbSeriesN = 2;
spaceAvail = nmosTop - (stdCell.getCellBot() + wellOverhangDiff);
totWid = sz * 3 * nbSeriesN;
FoldsAndWidth fwN = stdCell.calcFoldsAndWidth(spaceAvail, totWid, 2);
error(fwN==null, "can't make "+nm+" this small: "+sz);
// create NAND Part
Cell nand = stdCell.findPart(nm, sz);
if (nand!=null) return nand;
nand = stdCell.newPart(nm, sz);
// leave vertical m1 track for inb
double inbX = 1.5 + 2; // m1_m1_sp/2 + m1_wid/2
double nmosX = inbX + 2 + 3 + 2;// m1_wid/2 + m1_m1_sp + diffCont_wid/2
// NMOS
double nmosY = nmosTop - fwN.physWid/2;
int nbSeries = 2;
FoldedMos nmos = new FoldedNmos(nmosX, nmosY, fwN.nbFolds, nbSeries,
fwN.gateWid, nand, tech);
// Create multiple FoldedPmos. Each FoldedPmos has, at most, 2
// folds.
FoldedMos[] pmoss = new FoldedMos[(int) Math.ceil(fwP.nbFolds/2.0)];
double pmosY = pmosBot + fwP.physWid/2;
for (int nbFoldsP=0; nbFoldsP<fwP.nbFolds; nbFoldsP+=2) {
int nbFolds = Math.min(2, fwP.nbFolds-nbFoldsP);
nbSeries = 1;
double pmosPitch = 2 * 13;
// pmos is shifted right by 2 lambda to allow weak PMOS to share drain
double pmosX = nmosX + 2 + pmosPitch * (nbFoldsP/2);
pmoss[nbFoldsP/2] = new FoldedPmos(pmosX, pmosY, nbFolds, nbSeries,
fwP.gateWid, nand, tech);
}
stdCell.fillDiffAndSelectNotches(pmoss, true);
// Create weak PMOS
double rightDiffX = StdCellParams.getRightDiffX(pmoss, nmos);
// unrelated diffusion pitch is 8.5 lambda
double weakX = rightDiffX + 8.5;
double weakY = pmosBot + fwW.physWid/2;
FoldedMos weakPmos = new FoldedPmos(weakX, weakY, fwW.nbFolds, 1,
fwW.gateWid, nand, tech);
// create an array that holds all PMOS, strong and weak
FoldedMos[] stroWeakPmoss = new FoldedMos[pmoss.length+1];
for (int i=0; i<pmoss.length; i++) {
stroWeakPmoss[i] = pmoss[i];
}
stroWeakPmoss[pmoss.length] = weakPmos;
// create vdd and gnd exports and connect to MOS source/drains
stdCell.wireVddGnd(nmos, StdCellParams.EVEN, nand);
stdCell.wireVddGnd(stroWeakPmoss, StdCellParams.EVEN, nand);
// Nand input B
LayoutLib.newExport(nand, "inb", PortCharacteristic.IN, tech.m1(),
4, inbX, inbY);
TrackRouter inb = new TrackRouterH(tech.m1(), 3, inbY, tech, nand);
inb.connect(nand.findExport("inb"));
for (int i=0; i<nmos.nbGates(); i++) {
switch (i%4) {
case 0: inb.connect(nmos.getGate(i, 'T')); break;
case 2: inb.connect(nmos.getGate(i, 'T'), -1.5); break;
}
}
for (int i=0; i<pmoss.length; i++) {
for (int j=0; j<pmoss[i].nbGates(); j++) {
switch (j) {
case 0: inb.connect(pmoss[i].getGate(j, 'B'), -2); break;
case 1: inb.connect(pmoss[i].getGate(j, 'B'), 1.5); break;
}
}
}
// Nand input A
// m1_wid + m1_space + m1_wid/2
double inaX = StdCellParams.getRightDiffX(weakPmos, nmos) + 2 + 3 + 2;
LayoutLib.newExport(nand, "ina", PortCharacteristic.IN, tech.m1(),
4, inaX, inaY);
TrackRouter ina = new TrackRouterH(tech.m1(), 3, inaY, tech, nand);
ina.connect(nand.findExport("ina"));
for (int i=0; i<nmos.nbGates(); i++) {
if (i%2 == 1) ina.connect(nmos.getGate(i, 'T'), 1.5);
}
for (int i=0; i<weakPmos.nbGates(); i++) {
ina.connect(weakPmos.getGate(i, 'B'), 1.5);
}
// Nand output
double outX = inaX + 2 + 3 + 2; // m1_wid/2 + m1_sp + m1_wid/2
LayoutLib.newExport(nand, "out", PortCharacteristic.OUT, tech.m1(),
4, outX, outHiY);
TrackRouter outHi = new TrackRouterH(tech.m2(), 4, outHiY, tech, nand);
outHi.connect(nand.findExport("out"));
for (int i=0; i<stroWeakPmoss.length; i++) {
for (int j=1; j<stroWeakPmoss[i].nbSrcDrns(); j+=2) {
outHi.connect(stroWeakPmoss[i].getSrcDrn(j));
}
}
TrackRouter outLo = new TrackRouterH(tech.m2(), 4, outLoY, tech, nand);
outLo.connect(nand.findExport("out"));
for (int i=1; i<nmos.nbSrcDrns(); i+=2) {
outLo.connect(nmos.getSrcDrn(i));
}
// add wells
double wellMinX = 0;
double wellMaxX = outX + 2 + 1.5; // m1_wid/2 + m1m1_space/2
stdCell.addNmosWell(wellMinX, wellMaxX, nand);
stdCell.addPmosWell(wellMinX, wellMaxX, nand);
// add essential bounds
stdCell.addEssentialBounds(wellMinX, wellMaxX, nand);
// perform Network Consistency Check
stdCell.doNCC(nand, nm+"{sch}");
return nand;
}
}