Write a test bench for the elevator controller of Problem 5.10. The test bench has two functions: to simulate the operation of the elevator (including the door operation) and to provide a sequence of button pushes to test the operation of the controller.
To simulate the elevator: if the elevator is on the first floor (FS₁= 1) and an UP signal is received, wait 1 second and turn off FS₁; then wait 10 seconds and turn on FS₂; this simulates the elevator moving from the first floor to the second. Similar action should occur if the elevator is on the second floor (FS₂= 1) and a DOWN signal is received. When a door open signal is received (DO = 1), set door closed (DC) to 0, wait 5 seconds, and then set DC = 1.
Test sequence: CALL1, 2, FB2, 4, FB1, 1, CALL2, 10, FB2 Assume each button is held down for 1 second and then released. The numbers between buttons are the delays in seconds between button pushes; this delay is in addition to the 1 second the button is held down. Complete the following test bench:

module test_el;
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elev_control eltest(CALL1, CALL2, FB1, FB2, FS1, FS2, DC, CLK,
UP, DOWN, DO);
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endmodule

Data from Problem 5-10.

The block diagram for an elevator controller for a building with two floors is shown in the following diagram. The inputs FB₁ and FB₂ are floor buttons in the elevator. The inputs CALL₁ and CALL₂ are call buttons in the hall. The inputs FS₁ and FS₂ are floor switches that output a 1 when the elevator is at the first or second floor landing. Outputs UP and DOWN control the motor, and the elevator is stopped when UP = DOWN = 0. N₁ and N₂ are flip-flops that indicate when the elevator is needed on the first or second floor. R₁ and R₂ are signals that reset these flip-flops. DO = 1 causes the door to open, and DC = 1 indicates that the door is closed. Draw an SM chart for the elevator controller (four states).

Transcribed Image Text:

|R2 FB1→ Storage R1 circuit N1 CALL, FB2→ Elevator Storage N2 UP control circuit CALL2→ circuit DOWN FS, FS2 | DO Door mechanism DC