User: Lets imagine a very simple computer , one which does only the following : increment / decrement / show / set a number. I want you to give a detailed overview of the implementation in form of a Electronic computer.
Assistant: Creating a simple electronic computer that can increment, decrement, show, and set a number involves designing a basic digital system. Let’s break down the implementation into its fundamental components and describe how each part contributes to the overall functionality:

### Components

1. **Registers:**
   - A register is a small storage area that holds the number which is being manipulated. For this computer, you would need:
     - **Main Register (R):** Stores the current value (number) being worked with.

2. **Control Unit:**
   - The control unit handles the command input and determines what action to take. The commands are:
     - **Increment (INC)**
     - **Decrement (DEC)**
     - **Show (SHW)**
     - **Set (SET)**

3. **Arithmetic Logic Unit (ALU):**
   - This component performs basic arithmetic operations.
     - **Increment/Decrement:** Add 1 to or subtract 1 from the value in the main register.

4. **Input/Output Interface:**
   - A simple I/O interface is needed to receive commands and display results.
     - **Input Control:** Buttons or switches to input commands (INC, DEC, SHW, SET).
     - **Output Display:** A digital display (like a 7-segment LED display) to show the current value of the main register.

5. **Clock:**
   - A clock signal synchronizes the operations of the computer, ensuring that changes happen in a controlled manner.

6. **Memory (optional for SET):**
   - A small memory or a series of switches can be used to input and store a specific number that’s set to the main register.

### Implementation

1. **Register Setup:**
   - Use a simple flip-flop-based register to store a binary number. For example, a 4-bit register can hold numbers from 0 to 15, allowing basic operations within this range.

2. **Control Logic:**
   - Design logic gates that interpret the input commands:
     - **Increment (INC):** Activate the ALU to add 1 to the register's value.
     - **Decrement (DEC):** Activate the ALU to subtract 1 from the register's value.
     - **Show (SHW):** Output the current value in the register to the display.
     - **Set (SET):** Load a specific value into the register from the input.

3. **ALU Design:**
   - A minimal ALU is needed to perform addition and subtraction:
     - Use a simple binary adder circuit (half-adder/full-adder) for incrementing.
     - For decrementing, use the adder with a subtract control (using two's complement representation).

4. **Input Controls:**
   - Implement physical push buttons or switches for each command. Design a debouncing circuit to ensure clean input signals.

5. **Display Interface:**
   - Connect the output of the register to a binary-to-7-segment decoder that drives the digital display.

6. **Clock Regulation:**
   - A clock circuit ensures operations occur in discrete steps. This could be a simple oscillator circuit generating a steady pulse to move the state machine controlling the operations.

### Example Operation Cycle

- **Increment (INC):**
  1. User presses the INC button.
  2. The control unit sends an “add 1” signal to the ALU.
  3. The ALU processes the addition, updates the register.
  4. The updated value in the register is optionally shown on the display.

- **Decrement (DEC):**
  1. User presses the DEC button.
  2. The control unit signals the ALU to subtract 1.
  3. The value is decremented and stored back in the register.
  4. Display updates (if in show mode).

- **Show (SHW):**
  1. User presses SHW.
  2. Control unit sends the register value to the display unit.

- **Set (SET):**
  1. User selects/inputs a number using a series of switches.
  2. Press SET.
  3. The selected number is loaded into the register.

This simple computer model illustrates the basic principles of sequential logic design and how fundamental computer operations interact at the hardware level. Such a system could be expanded with additional features, such as error checking or larger bit-widths for handling larger numbers.
User: can you code a simple text based simulation program for this design in python ?

Assistant: