Puzzle 71 of 100

Both outputs

Goal

Make Q go high when S is high and low when R is high, and make QN its inverse. While S and R are both high, Q and QN are both low.

Die: 21 by 12 squares
Layers: Metal, Polysilicon, Contact, N active, P active, N well, Metal 2, Via
Inputs: S, R
Outputs: Q, QN
Supply: VDD
Ground: GND

Go to the solution

New in this puzzle

Both inputs high

While S and R are both high, both NOR outputs are low, so QN is not the inverse of Q. When one input falls, the one still high decides the level the latch keeps.

Hint

Build the NOR latch of the earlier puzzle on the empty die and give each output its own pad. Q comes from the gate that takes R, and QN from the gate that takes S.

Solution

This is the game's reference drawing for the puzzle. It meets the goal and passes the design rules. Other drawings can pass as well.

Top View of the solved die for puzzle 71, Both outputs, with the Side View below it. — Top View of the solved die, captured from the game. Paths that carry a high level at the moment shown are lit. The Side View below cuts through the row between the dashed lines.

The game window in Isometric View with the solved die for puzzle 71, Both outputs, the guide, and the scope. — The whole game window in Isometric View. The scope on the right compares each output with its target band, and the message above it confirms that the drawing passes.

Solution drawing for puzzle 71, Both outputs, drawn on a numbered grid with every layer in its game color and pattern. — The solution on the grid. Squares are numbered from the top left corner, so you can count them. The dashed outline marks the squares you draw, change, or erase; the rest is drawn when the puzzle opens.

Legend

Metal106 squares
Polysilicon44 squares
Contact18 squares
N active10 squares
P active20 squares
N well52 squares
Input padS, R
Output padQ, QN
Supply padVDD
Ground padGND
Squares you draw, change, or erase124 squares

About the drawing

The drawing uses 166 of the die's 252 squares.
Part of the drawing is in place when the puzzle opens. To finish it, paint 124 empty squares.
It forms 8 transistors: 4 N transistors and 4 P transistors. Each one is a place where polysilicon crosses active silicon.
18 contacts join metal to the polysilicon or active silicon under it.

Starting drawing for puzzle 71, Both outputs, on a numbered grid. — The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.