Jul 18, 2015 · Since all of the units we’ve created so far have enable ports, we can get a control unit to synchronize everything up and drive those enable bits. The control unit will have one output, a bitmask showing the pipeline state currently active, as well as a reset and clock input.

I have designed the Control Unit of the CPU in VHDL. It works properly and produces the expected simulation waveforms. Nevertheless, I feel that my existing code can be improved considerably. My control unit essentially consists of three processes: operation decoder (this is the lengthiest process.

Aug 6, 2017 · Control Unit. From a very high-level perspective, all the CPU core does is to load an instruction from memory into an instruction register, decode it, process it, update the program counter, fetch the next instruction and so on. Katz calls the part that manages these states as the processor control unit and presents a simple high-level state ...

Aug 11, 2020 · The control unit for the instructional processor is a hardwired controller which generates control signals using a control step counter and the various fields from the instruction register. The organization of the control unit is shown in Figure 4 [5]. The unit is designed as a finite state machine which implements the fetch, decode, and

The control unit of the processor reads an instruction from memory, generates the appropriate control signals for the rest of the processor, and handles program branches.

• The steps that the control unit carries out in executing a program are: (1) Fetch the next instruction to be executed from memory. (2) Decode the opcode. (3) Read operand(s) from main memory, if any. (4) Execute the instruction and store results. (5) Go to step 1.

The control unit receives the current instruction from the datapath and tells the datapath how to execute that instruction. Specifically, the control unit produces multiplexer select, register enable, and memory write signals to control the operation of the datapath.

Jul 23, 2015 · Our PC unit will obviously hold the current PC, and on command increment it. It will have an input for setting the next PC value, and also the ability to stop – stay at the same location – which we need due to our pipeline being several cycles long.

The control unit will generate control signals for each component in the design, based on the current state (given by the phase generator) and on the instruction code. The control signals are the following:

The single cycle CPU we have designed is comprised of nine primary units that we will describe in detail individually. These units, which are shown in figure 1, are: program counter, instruction memory, register file, ALU, data memory, control unit, …