EET230L Digital Systems Lab
Project 4
Design a One-Hz Clock By Using Frequency Division Method
I. Due time: At the end of the class.
II. Requirements: You must demo your PLD implementation to your instructor.
III. The project: Design a circuit to convert on-board clock to a one-Hz clock.
IV. Part I: Design a circuit and a chip called "FiveHz_Clock"
1. Our DE0 board has an on-board clock that produces a 50MHz square wave signal: 50MHz = 5 x 10^7 Hz.
2. Inside the EET 230L folder, create a Windows folder called "My Clock."
3. Inside the My Clock folder, use Quartus II to create a folder and a project called FiveHz_Clock.
4. In the FiveHz_Clock project, design a circuit to divide the frequency of the on-board clock to a 5Hz clock. You need to cascade seven decade counter chips 74160 (mod 10) to generate a counter with the total mod: 10 x 10 x 10 x 10 x 10 x 10 x 10 = 10^7.
5. Set all CLRN and LDN to high. Set all parallel inputs A, B, C, D to low. First set ENT and ENP to high; all the remaining ENT and ENP are connected to the previous chip's RCO. Use a single clock to trigger all counters. Your circuit should have one input called "Clock," and one output called "RCO."
6. Create a block symbol (chip) for your circuit.
7. Save your project, then compile your project.
Part II: Design a circuit and a chip called "OneHz_Clock"
8. Inside the My Clock folder, but outside all other folders, use Quartus II to create a folder and a project called OneHz_Clock.
9. In the OneHz_Clock project, design a circuit to truncate a Mod 16 synchronous binary counter 74161 to a Mod 5 counter. Use a NAND gate to clear the counter when the counter generates the outputs 0101 = 5. Use an AND gate to generate an output called "OneHz" which will go high when the counter generates the outputs 0100 = 4. Set the load pin high, and all the parallel input pins low.
10. Use the FiveHz_Clock chip to drive this Mod5_Counter. A single input called Clock is used to connect to the clock pins of both the FiveHz_Clock chip and the Mod 5 counter. The RCO of the FiveHz_Clock chip is connected to both ENT and ENP of the Mod 5 counter. Your circuit should have one input called "Clock," and one output called "OneHz."
11. Create a chip (block symbol) for your circuit.
12. Save your project, then compile your project.