Tank Level Decoder (K-Map)

A rainwater tank reports its fill level on a 4-bit bus level (l3 l2 l1 l0, 0 = empty, 15 = full). The control board needs two outputs, specified by the table below: a drain pump that runs when the tank is nearly full, and a low-level warning. Plot each output column on a 4×4 Karnaugh map, read off the minimal groups, and implement the result as gates.

Truth Table

Level	`l3 l2 l1 l0`	`low`	Level	`l3 l2 l1 l0`	`pump`
0	`0000`	1	8	`1000`	0
1	`0001`	1	9	`1001`	0
2	`0010`	1	10	`1010`	1
3	`0011`	1	11	`1011`	1
4	`0100`	0	12	`1100`	1
5	`0101`	0	13	`1101`	1
6	`0110`	0	14	`1110`	1
7	`0111`	0	15	`1111`	1

Interface

Port	Direction	Type	Description
`level`	in	4-bit vector	Tank fill level, 0 to 15
`pump`	out	1 bit	Drain pump on
`low`	out	1 bit	Low-level warning

Behavior

pump and low match their truth-table columns for every one of the 16 input values; the testbench sweeps them all
The outputs are pure functions of level: no state, no clock

Constraints

OPERATORS

build each output from individual bits of level using only and, or, not (&, |, ~); no arithmetic, no comparisons.

Implement the K-map result: low is a single two-literal term, and pump is two two-literal terms ORed. The testbench can only check values, but anything bigger means your groups are too small.

combinational decoder

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